Topic Editors

Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, University of Santiago de Compostela, Campus univ. s/n, 27002 Lugo, Spain
William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
INSTM and Chemistry for Technologies Laboratory, Department of Mechanical and Industrial Engineering, University of Brescia, Via Branze 38, 25123 Brescia, Italy
CNR—National Research Council of Italy, Research Institute on Sustainable Economic Growth, Collegio Carlo Alberto, Via Real Collegio, 30-10024 Moncalieri (Torino), Italy
Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via di Biasio 43, 03043 Cassino, Italy
College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China

New Research on Detection and Removal of Emerging Pollutants

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Topic Information

Dear Colleagues,

Emerging pollutants are a very relevant concern as regards environmental quality and public health. Air, soil, and water, as well as living organisms, and then the whole food chain, may be affected by these kinds of contaminants.

Some of them have been the focus of researchers for years—firstly, to detect it and then for achieving their removal or immobilization/inactivation. Both inorganic and organic emerging pollutants, as well as microbial emerging contaminants, are increasingly being considered a crucial threat for ecosystems and for a diversity of living beings, which has resulted in growing efforts and resources dedicated to lines of research in this regard. Many different aspects should be considered when evaluating these issues globally, including those in social and political fields.

The editors handling this topic cover a broad spectrum within this field of research and would like to encourage all authors interested to submit their best manuscripts related to emerging pollutants, whether research papers, reviews, short communications, perspectives, etc. The aim is to achieve a final set of papers that significantly improve the knowledge within this promising field, as well as open new views and perspectives where appropriate.

Prof. Dr. Avelino Núñez-Delgado
Dr. Zhien Zhang
Prof. Dr. Elza Bontempi
Dr. Mario Coccia
Dr. Marco Race
Prof. Dr. Yaoyu Zhou
Topic Editors

Keywords

  • air pollution
  • emerging contaminants
  • water pollution
  • sorbent materials
  • soil pollution

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Processes
processes
2.8 5.1 2013 14.4 Days CHF 2400
Applied Sciences
applsci
2.5 5.3 2011 17.8 Days CHF 2400
Materials
materials
3.1 5.8 2008 15.5 Days CHF 2600
Sustainability
sustainability
3.3 6.8 2009 20 Days CHF 2400
Toxics
toxics
3.9 4.5 2013 15.6 Days CHF 2600

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Published Papers (67 papers)

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2 pages, 202 KiB  
Editorial
Editorial on the Topic “New Research on Detection and Removal of Emerging Pollutants”
by Avelino Núñez-Delgado, Zhien Zhang, Elza Bontempi, Mario Coccia, Marco Race and Yaoyu Zhou
Materials 2023, 16(2), 725; https://doi.org/10.3390/ma16020725 - 11 Jan 2023
Cited by 13 | Viewed by 1437
Abstract
With the Topic “New Research on Detection and Removal of Emerging Pollutants” (https://www [...] Full article
4 pages, 212 KiB  
Editorial
Our Environment: Everything Is Natural on Earth, but … Editorial Piece on Current and Future Soil and Environmental Research
by Avelino Núñez Delgado
Processes 2023, 11(1), 6; https://doi.org/10.3390/pr11010006 - 20 Dec 2022
Cited by 5 | Viewed by 1356
Abstract
When finishing the Topical Issue “New Research on Detection and Removal of Emerging Pollutants”, some reflections came to my mind, which I include in the piece below [...] Full article
13 pages, 5553 KiB  
Article
Enhanced Photocatalytic Performance of Bi2O2CO3 Loaded Activated Carbon for Toluene Removal in Air
by Xiaoyan Wang, Lu Chen, Changfu Li, Yongchao Xiao, Yuchen Gao, Yaochun Liu, Yuanhua Lin and Junping Ding
Appl. Sci. 2022, 12(23), 12500; https://doi.org/10.3390/app122312500 - 6 Dec 2022
Cited by 1 | Viewed by 1333
Abstract
Activated carbon (AC) is one of the most used air purification materials with excellent adsorption capacity for volatile organic compounds (VOCs). In this work, Bi2O2CO3 (BOC) nanomaterials, as a photocatalysis component, are grown on the surface of the [...] Read more.
Activated carbon (AC) is one of the most used air purification materials with excellent adsorption capacity for volatile organic compounds (VOCs). In this work, Bi2O2CO3 (BOC) nanomaterials, as a photocatalysis component, are grown on the surface of the AC to construct BOC/AC composites. The as-synthesized composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and N2 adsorption/desorption measurements. The results demonstrate that flower-like BOC can be grown in situ on the surface of AC. The photocatalytic properties for the removal of gaseous toluene (50.0 ppm) in air over the BOC/AC composites were investigated under simulated sunlight illumination. The results show that the BOC/AC photocatalyst can effectively degrade toluene to CO2 and H2O, with more than 90% degradation in 3 h. The excellent photocatalytic performance of the BOC/AC composite catalyst can be ascribed to the synergistic effect of the adsorption ability of AC and photocatalytic activity of both BOC nanosheets and AC. This work may provide useful guidance for indoor air purification, particularly for harmful trace gases such as VOCs. Full article
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10 pages, 2444 KiB  
Article
Azithromycin Adsorption onto Different Soils
by Raquel Cela-Dablanca, Ana Barreiro, Lucía Rodríguez-López, Paula Pérez-Rodríguez, Manuel Arias-Estévez, María J. Fernández-Sanjurjo, Esperanza Álvarez-Rodríguez and Avelino Núñez-Delgado
Processes 2022, 10(12), 2565; https://doi.org/10.3390/pr10122565 - 2 Dec 2022
Cited by 3 | Viewed by 1905
Abstract
The antibiotic azithromycin (AZM) is one of the most persistent in the environment, with potential to cause serious health and environmental problems. As some polluting discharges containing this antibiotic can reach the soil, it is clearly relevant determining the ability of soils with [...] Read more.
The antibiotic azithromycin (AZM) is one of the most persistent in the environment, with potential to cause serious health and environmental problems. As some polluting discharges containing this antibiotic can reach the soil, it is clearly relevant determining the ability of soils with different characteristics to retain it. In this research, AZM adsorption and desorption were studied for a variety of soils, using batch-type experiments. The results show that, at low doses of antibiotic added (less than or equal to 50 µmol L−1), the adsorption always reached 100%, while when higher concentrations were added (between 200 and 600 µmol L−1) the highest adsorption corresponded to soils with higher pH values. Adsorption data were fitted to the Linear, Langmuir and Freundlich models, with the latter showing the best fit, in view of the determination coefficient. No desorption was detected, indicating that AZM is strongly adsorbed to the soils evaluated, suggesting that the risks of environmental problems due to this contaminant are minimized for these edaphic media. These results can be considered relevant with respect to risk assessment and possible programming of measures aimed at controlling environmental contamination by emerging contaminants, especially from the group of antibiotics, and in particular from AZM. Full article
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16 pages, 2716 KiB  
Article
Pitting and General Corrosion Susceptibilities of Materials for High Level Radioactive Waste (HLW) Disposal
by Brent Verhoeven, Walter Bogaerts, Pieter Van Aken, Roberto Gaggiano, Jan Baeyens, Barbara Rossi and Raf Dewil
Materials 2022, 15(18), 6464; https://doi.org/10.3390/ma15186464 - 17 Sep 2022
Cited by 1 | Viewed by 1851
Abstract
The disposal of high-level radioactive waste (HLW) in deep stable geological formations is accepted at an international level to be the most promising option for its long-term management. The supercontainer concept is currently being considered as the Belgian reference design, wherein the waste [...] Read more.
The disposal of high-level radioactive waste (HLW) in deep stable geological formations is accepted at an international level to be the most promising option for its long-term management. The supercontainer concept is currently being considered as the Belgian reference design, wherein the waste will be stored in geological stable clay formations. The outer barrier of the supercontainer is the envelope, which should be made of a corrosion-resistant material as it will be in contact with the aggressive species leaching from the host rock (i.e., chloride) and diffusing through the cementitious barriers of the disposal system. Polarization measurements are carried out to study the pitting susceptibility and the uniform corrosion of possible candidate materials in chloride-rich concrete pore solutions, aerated by high-purity oxygen. The tests are carried out at a deep soil-representative temperature of 60 °C. All materials showed high pitting resistance in aerated concrete pore solutions and can withstand chloride concentrations up to 1 M. Regular 316L and LDX2304 stainless steel also showed good corrosion resistance and can serve as a more economical alternative. The pH of the used pore solutions did affect the measured corrosion rate irrespective of the alloying elements inside the steel grades. Full article
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21 pages, 9544 KiB  
Article
Cu and As(V) Adsorption and Desorption on/from Different Soils and Bio-Adsorbents
by Raquel Cela-Dablanca, Ana Barreiro, Gustavo Ferreira-Coelho, Claudia Campillo-Cora, Paula Pérez-Rodríguez, Manuel Arias-Estévez, Avelino Núñez-Delgado, Esperanza Álvarez-Rodríguez and María J. Fernández-Sanjurjo
Materials 2022, 15(14), 5023; https://doi.org/10.3390/ma15145023 - 19 Jul 2022
Cited by 4 | Viewed by 1661
Abstract
This research is concerned with the adsorption and desorption of Cu and As(V) on/from different soils and by-products. Both contaminants may reach soils by the spreading of manure/slurries, wastewater, sewage sludge, or pesticides, and also due to pollution caused by mining and industrial [...] Read more.
This research is concerned with the adsorption and desorption of Cu and As(V) on/from different soils and by-products. Both contaminants may reach soils by the spreading of manure/slurries, wastewater, sewage sludge, or pesticides, and also due to pollution caused by mining and industrial activities. Different crop soils were sampled in A Limia (AL) and Sarria (S) (Galicia, NW Spain). Three low-cost by-products were selected to evaluate their bio-adsorbent potential: pine bark, oak ash, and mussel shell. The adsorption/desorption studies were carried out by means of batch-type experiments, adding increasing and individual concentrations of Cu and As(V). The fit of the adsorption data to the Langmuir, Freundlich, and Temkin models was assessed, with good results in some cases, but with high estimation errors in others. Cu retention was higher in soils with high organic matter and/or pH, reaching almost 100%, while the desorption was less than 15%. The As(V) adsorption percentage clearly decreased for higher As doses, especially in S soils, from 60–100% to 10–40%. The As(V) desorption was closely related to soil acidity, being higher for soils with higher pH values (S soils), in which up to 66% of the As(V) previously adsorbed can be desorbed. The three by-products showed high Cu adsorption, especially oak ash, which adsorbed all the Cu added in a rather irreversible manner. Oak ash also adsorbed a high amount of As(V) (>80%) in a rather non-reversible way, while mussel shell adsorbed between 7 and 33% of the added As(V), and pine bark adsorbed less than 12%, with both by-products reaching 35% desorption. Based on the adsorption and desorption data, oak ash performed as an excellent adsorbent for both Cu and As(V), a fact favored by its high pH and the presence of non-crystalline minerals and different oxides and carbonates. Overall, the results of this research can be relevant when designing strategies to prevent Cu and As(V) pollution affecting soils, waterbodies, and plants, and therefore have repercussions on public health and the environment. Full article
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13 pages, 1890 KiB  
Article
Indoor Air Quality Considerations for Laboratory Animals in Wildfire-Impacted Regions—A Pilot Study
by Adam Schuller, Ethan S. Walker, Jaclyn M. Goodrich, Matthew Lundgren and Luke Montrose
Toxics 2022, 10(7), 387; https://doi.org/10.3390/toxics10070387 - 12 Jul 2022
Cited by 2 | Viewed by 2468
Abstract
Wildfire events are increasing across the globe. The smoke generated as a result of this changing fire landscape is potentially more toxic than air pollution from other ambient sources, according to recent studies. This is especially concerning for populations of humans or animals [...] Read more.
Wildfire events are increasing across the globe. The smoke generated as a result of this changing fire landscape is potentially more toxic than air pollution from other ambient sources, according to recent studies. This is especially concerning for populations of humans or animals that live downwind of areas that burn frequently, given that ambient exposure to wildfire smoke cannot be easily eliminated. We hypothesized that a significant indoor air pollution risk existed for laboratory animal facilities located proximal to fire-prone areas. Here, we measured real time continuous outdoor and indoor air quality for 28 days at a laboratory animal facility located in the Rocky Mountain region. We demonstrated that during a wildfire event, the indoor air quality of this animal facility is influenced by ambient smoke events. The daily average indoor fine particulate matter value in an animal room exceeded the Environmental Protection Agency’s ambient annual standard 14% of the time and exceeded the World Health Organization’s ambient annual guideline 71% of the time. We further show that specialized cage filtration systems are capable of mitigating air pollution penetrance and could improve an animal’s microenvironment. The potential effects for laboratory animal physiology that occur in response to the exposure levels and durations measured in this study remain to be determined; yet, even acute wildfire exposure events have been previously correlated with significant differences in gene regulatory and metabolic processes in vivo. We believe these findings warrant consideration for indoor laboratory animal facility air quality monitoring and development of smoke exposure prevention and response protocols, especially among facilities located downwind of fire-prone landscapes. Full article
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10 pages, 1179 KiB  
Article
Correlation between the Desiccator Method and 1 m³ Climate Chamber Method for Measuring Formaldehyde Emissions from Veneered Particleboard
by Jia Shao, Yang Chen, Ling Dong, Tangfeng Yuan, Zhongfeng Zhang and Jijuan Zhang
Processes 2022, 10(5), 1023; https://doi.org/10.3390/pr10051023 - 20 May 2022
Cited by 5 | Viewed by 2015
Abstract
To shorten the measuring time of formaldehyde emissions from wood-based panels and reduce the costs of quality control processes during industrial furniture production, more efficient methods for measuring formaldehyde emissions from wood-based panels need to be developed. In this study, the formaldehyde emissions [...] Read more.
To shorten the measuring time of formaldehyde emissions from wood-based panels and reduce the costs of quality control processes during industrial furniture production, more efficient methods for measuring formaldehyde emissions from wood-based panels need to be developed. In this study, the formaldehyde emissions from 18-mm-thick veneered particleboard were measured using the desiccator method and the 1 m3 climate chamber method according to Chinese national standard GB/T17657-2013, and the correlation between these two methods was determined. Through a correlation analysis of 60 groups of data, the results indicated that the linear correlation coefficient (R) between two methods was 0.718, and the regression model was established, which by F and P values demonstrated a significant correlation at the 0.01 level of significance. As long as the quality of materials and the production processes remained consistent, the desiccator method was reliable enough for conducting routine quality control measurements of formaldehyde emissions from veneered boards of 18 mm thickness. In case of dispute, the results can be verified using the 1 m3 climate chamber method for accuracy. Full article
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10 pages, 1354 KiB  
Article
Colony-Forming Efficiency Assay to Assess Nanotoxicity of Graphene Nanomaterials
by Hansol Won, Sung-Hyun Kim, Jun-Young Yang, Kikyung Jung, Jayoung Jeong, Jae-Ho Oh and Jin-Hee Lee
Toxics 2022, 10(5), 236; https://doi.org/10.3390/toxics10050236 - 5 May 2022
Cited by 3 | Viewed by 2548
Abstract
The nano-market has grown rapidly over the past decades and a wide variety of products are now being manufactured, including those for biomedical applications. Despite the widespread use of nanomaterials in various industries, safety and health effects on humans are still controversial, and [...] Read more.
The nano-market has grown rapidly over the past decades and a wide variety of products are now being manufactured, including those for biomedical applications. Despite the widespread use of nanomaterials in various industries, safety and health effects on humans are still controversial, and testing methods for nanotoxicity have not yet been clearly established. Nanomaterials have been reported to interfere with conventional cytotoxicity tests due to their unique properties, such as light absorption or light scattering. In this regard, the colony-forming efficacy (CFE) assay has been suggested as a suitable test method for testing some nanomaterials without these color-interferences. In this study, we selected two types of GNPs (Graphene nanoplatelets) as test nanomaterials and evaluated CFE assay to assess the cytotoxicity of GNPs. Moreover, for further investigation, including expansion into other cell types, GNPs were evaluated by the conventional cytotoxicity tests including the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS), Cell Counting Kit-8 (CCK-8), and Neutral red uptake (NRU) assay using MDCK, A549 and HepG2 cells. The results of CFE assay suggest that this test method for three cell lines can be applied for GNPs. In addition, the CFE assay was able to evaluate cytotoxicity regardless more accurately of color interference caused by residual nanomaterials. Full article
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12 pages, 837 KiB  
Article
Amoxicillin Retention/Release in Agricultural Soils Amended with Different Bio-Adsorbent Materials
by Raquel Cela-Dablanca, Ana Barreiro, Lucia Rodríguez-López, Vanesa Santás-Miguel, Manuel Arias-Estévez, María J. Fernández-Sanjurjo, Esperanza Álvarez-Rodríguez and Avelino Núñez-Delgado
Materials 2022, 15(9), 3200; https://doi.org/10.3390/ma15093200 - 28 Apr 2022
Cited by 10 | Viewed by 1785
Abstract
The antibiotic amoxicillin (AMX) may reach soils and other environmental compartments as a pollutant, with potential to affect human and environmental health. To solve/minimize these hazards, it would be clearly interesting to develop effective and low-cost methods allowing the retention/removal of this compound. [...] Read more.
The antibiotic amoxicillin (AMX) may reach soils and other environmental compartments as a pollutant, with potential to affect human and environmental health. To solve/minimize these hazards, it would be clearly interesting to develop effective and low-cost methods allowing the retention/removal of this compound. With these aspects in mind, this work focuses on studying the adsorption/desorption of AMX in different agricultural soils, with and without the amendment of three bio-adsorbents, specifically, pine bark, wood ash and mussel shell. For performing the research, batch-type experiments were carried out, adding increasing concentrations of the antibiotic to soil samples with and without the amendment of these three bio-adsorbents. The results showed that the amendments increased AMX adsorption, with pine bark being the most effective. Among the adsorption models that were tested, the Freundlich equation was the one showing the best fit to the empirical adsorption results. Regarding the desorption values, there was a decrease affecting the soils to which the bio-adsorbents were added, with overall desorption not exceeding 6% in any case. In general, the results indicate that the bio-adsorbents under study contributed to retaining AMX in the soils in which they were applied, and therefore reduced the risk of contamination by this antibiotic, which can be considered useful and relevant to protect environmental quality and public health. Full article
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16 pages, 6238 KiB  
Article
Leaching Kinetics of Aluminum from Alkali-Fused Spent Cathode Carbon Using Hydrochloric Acid and Sodium Fluoride
by Jie Yuan, Huijin Li and Shuang Ding
Processes 2022, 10(5), 849; https://doi.org/10.3390/pr10050849 - 25 Apr 2022
Cited by 8 | Viewed by 2248
Abstract
Abundant carbon resides in spent cathode carbon (SCC) of aluminum electrolysis and its high-purity carbon powder is conducive to high-value recycling. The alkali-fused SCC was separated and effectively purified using an HCl/NaF solution. Effects of particle size, leaching temperature, time, initial acid concentration, [...] Read more.
Abundant carbon resides in spent cathode carbon (SCC) of aluminum electrolysis and its high-purity carbon powder is conducive to high-value recycling. The alkali-fused SCC was separated and effectively purified using an HCl/NaF solution. Effects of particle size, leaching temperature, time, initial acid concentration, and sodium fluoride dosage, on the purity of carbon powder and aluminum removal rate, were investigated. Using aluminum as the research object, kinetics of aluminum acid leaching were examined by single-factor experiments. Results showed that under an initial 4 M HCl concentration, particle size D(50) = 67.49 μm, liquid-solid ratio of 15:1, 333 K, 120 min, 0.3 M NaF, carbon powder with ash level below 1% were obtained in subsequent purification of SCC. The leaching process was described by Avram equation, the model characteristic parameter was 0.75147 and the apparent activation energy was 22.056 kJ/mol, which indicated a mixed control mechanism between chemical reactivity and diffusion. The kinetic reaction equation of leaching aluminum from alkali-fused SCC in a mixed HCl/NaF system was established. Full article
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12 pages, 4513 KiB  
Article
Selective Adsorption of Pb2+ in the Presence of Mg2+ by Layer-by-Layer Self-Assembled MnO2/Mxene Composite Films
by Hongjing Qu, Jiayan Deng, Dan Peng, Tong Wei, Hang Zhang and Ruichao Peng
Processes 2022, 10(4), 641; https://doi.org/10.3390/pr10040641 - 25 Mar 2022
Cited by 7 | Viewed by 2177
Abstract
A self-assembled MnO2/Mxene composite film was compounded with MXene nanosheets and layered crystalized MnO2 nanosheets using surfactant sodium dodecyl sulfate (SDS) as a soft template. The obtained material was characterized by XRD, SEM, XPS, and FT-IR, which showed that the [...] Read more.
A self-assembled MnO2/Mxene composite film was compounded with MXene nanosheets and layered crystalized MnO2 nanosheets using surfactant sodium dodecyl sulfate (SDS) as a soft template. The obtained material was characterized by XRD, SEM, XPS, and FT-IR, which showed that the films have large surface-active functional groups and metal ion flow channels, indicating that the MnO2/Mxene composite films were capable of both the chemical and physical adsorption of the target heavy metal ions. The analysis of adsorption performance showed that the Pb2+ removal rate reached 98.3% at pH 6 and an initial Pb2+ concentration of 30 mg/L, while the maximum adsorption capacity could reach 1235 µmol/g. In addition, the MnO2/Mxene composite film had specific selectivity and recyclability. The reuse study verified that the Pb2+ removal rate reached 96.4% after five cycles, confirming that the MnO2/Mxene composite films had practical application prospects. Full article
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8 pages, 348 KiB  
Article
Release of Microplastics from Reusable Kitchen Plasticware and Generation of Thermal Potential Toxic Degradation Products in the Oven
by Juri Jander, Darius Hummel, Sophie Stürmer, Adrian Monteleone, Tizian Neumaier, Felix Broghammer, Uta Lewin-Kretzschmar, Thomas Brock, Martin Knoll and Andreas Siegbert Fath
Appl. Sci. 2022, 12(5), 2535; https://doi.org/10.3390/app12052535 - 28 Feb 2022
Cited by 4 | Viewed by 7310
Abstract
Plastics are one of the most important technical materials at present, yet they are associated with a whole series of environmental problems such as micro-and nanoplastics or their plasticizers, which have become increasingly relevant in recent years. While there are many studies that [...] Read more.
Plastics are one of the most important technical materials at present, yet they are associated with a whole series of environmental problems such as micro-and nanoplastics or their plasticizers, which have become increasingly relevant in recent years. While there are many studies that focus on microplastics (MPs) introduced into the human body through commercially produced food, there are nearly none that consider the MPs we ingest through homemade food made with plastic kitchen utensils such as mixing bowls. To investigate this, samples were obtained by exposing different plastic bowls made of acrylonitrile–butadiene–styrene (ABS), polypropylene (PP), melamine, polyethylene (PE), polystyrene (PS), and styrene–acrylonitrile (SAN), to mechanical stress and then analyzed via infrared spectroscopy. This not only raises the question of whether microplastics are incorporated into foods but also the extent to which the degradation products produced by thermal stress in an oven could play a toxicological role. Degradation products were generated by pyrolysis and analyzed afterwards using gas chromatography mass spectrometry. There were differences in the number of microplastic particles abraded by the different types of plastic, with the most consisting of melamine (898 particles) and the least consisting of low-density polyethylene (331 particles). There were also differences in the number and relevance of the thermal degradation products for the different plastics, so that a human toxicological assessment would have to be evaluated in further work. Full article
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17 pages, 3522 KiB  
Article
The Effect of Sample Preparation and Measurement Techniques on Heavy Metals Concentrations in Soil: Case Study from Kraków, Poland, Europe
by Agnieszka Operacz, Adrianna Bigaj, Karolina Hap and Tomasz Kotowski
Appl. Sci. 2022, 12(4), 2137; https://doi.org/10.3390/app12042137 - 18 Feb 2022
Cited by 6 | Viewed by 3027
Abstract
Accurate and reliable laboratory results are an extremely important and integral part of conducting scientific research. Many factors influence the results obtained, including the type of determination method, accuracy and precision of measurements, and laboratory equipment used for the tests. This paper presents [...] Read more.
Accurate and reliable laboratory results are an extremely important and integral part of conducting scientific research. Many factors influence the results obtained, including the type of determination method, accuracy and precision of measurements, and laboratory equipment used for the tests. This paper presents the results of measurements of heavy metal concentration in soil using two methods for adding soil components into solution and different laboratory methods and types of measuring equipment. The first method used was hot digestion of soil samples with a mixture of concentrated HNO3 and HClO4, after prior ashing of organic matter (IUNG method). The second method was a two-stage decomposition, where soil samples were hot digested, initially with oxidizing acid (HNO3) and subsequently with non-oxidizing acid (HF) (two-stage decomposition). The concentrations of selected heavy metals (Cr, Cu, Fe, Mn, Ni, Pb and Zn) were determined in solutions obtained by both digestion methods. The solutions obtained from soil decomposition were determined twice using atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP MS) methods in different laboratories using different types of spectrometers. In most cases, the measured concentrations of heavy metals are the highest for the two-stage solution samples and the measurements of their concentrations carried out using ICP. The exceptions are the measurements of Cu and Ni concentrations. In the case of Cu, lack of significant differentiation in concentrations of this metal may result from different forms of occurrence of Cu in soil than in the case of other metals. For Ni, however, a reversal of the trends seen for the other metals is observed and the type of spectrometer used for measurements is important. There may be an interference of the spectrometric spectrum of Ni with the spectra of the other determined metals. However, this is not clear at the present stage of the study. In conclusion, the results of this study indicate that the choice of soil sample preparation and the type of spectrometer used for measurements can, in many cases, determine the value of laboratory results, even if it is in an expected range of standard material. Research of published papers proved that most of them show only results based on one selected course of methodology without comparison with others. The novelty of the paper is the comparison of the measurements of heavy metal concentration in soil using two methods for adding soil components into solution and different laboratory methods and types of measuring equipment. Additionally, the article includes a discussion of the importance of methodology. We believe that the conclusions may help to better understand how sample preparation and measurement methods applied may influence the results obtained. Full article
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8 pages, 1874 KiB  
Review
Imaging Method by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) for Tissue or Tumor: A Mini Review
by Jiawen Wu, Ze Rong, Peng Xiao and Yuanzhe Li
Processes 2022, 10(2), 388; https://doi.org/10.3390/pr10020388 - 17 Feb 2022
Cited by 2 | Viewed by 3061
Abstract
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is an advanced technique that uses minimum fragmented ions from complex molecules for mass spectrometry (MS) analysis (tissue profiling by mass spectrometry). It is able to analyze spatially resolved tissue or tumor sections at the molecular level. [...] Read more.
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is an advanced technique that uses minimum fragmented ions from complex molecules for mass spectrometry (MS) analysis (tissue profiling by mass spectrometry). It is able to analyze spatially resolved tissue or tumor sections at the molecular level. It has become a valuable tool for tumor and tissue imaging, due to its ease of operation and high mass resolution, but it still has vast room for development in the instrumentation of larger proteins in some tissues. In this review, we focus on the main components of MALDI-MS instrumentation, sample handling and processing, the working principle of MALDI-MS, and its applications in diagnostic and prognostic assessments, tumor removal and drug development. Although it is less effective at detecting larger proteins in some tissues, it still shows huge potential because of its advancements in instrumentation and processing protocols. This article may benefit those who have interests in MALDI-MS for tissue or tumor imaging. Full article
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14 pages, 6556 KiB  
Article
Radioactive Elements Detected in Abandoned Oil Tank Farms
by Stefan Petrache, Timur Chis, Ancaelena Eliza Sterpu and Olga Valerica Săpunaru
Processes 2022, 10(2), 374; https://doi.org/10.3390/pr10020374 - 15 Feb 2022
Cited by 2 | Viewed by 2340
Abstract
Oil fields in Romania were active in the period 1900–2020, some of which will close due to declining oil production and especially due to reduced processing after the application of European Community recommendations to give up fossil fuels and the use of renewable [...] Read more.
Oil fields in Romania were active in the period 1900–2020, some of which will close due to declining oil production and especially due to reduced processing after the application of European Community recommendations to give up fossil fuels and the use of renewable fuel. The rehabilitation of the soil affected by hydrocarbon pollution is carried out with public funds. This is why, when transferring the land to the local community, an oil pollution assessment study is carried out. If the hydrocarbon content is less than 1000 mg/kg dry matter, the soil is not depolluted. In the Moinesti oil area, Romania, against the background of the increased incidence of breast cancers in women who worked in oil facilities, a study was conducted on the natural radioactivity of abandoned oil areas. The results of this analysis are presented and discussed in this article. It is the first study of radioactivity of the oil tank farm affected by oil pollution, its purpose being to draw attention in detecting radioactive elements when handing over land affected by oil pollution (but which respects the maximum levels of pollutant) to the local community. Full article
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15 pages, 1535 KiB  
Article
Identification of Olfactory Nuisance of Floor Products Containing Bitumens with the TD–GC–MS/O Method
by Mateusz Kozicki
Materials 2022, 15(3), 959; https://doi.org/10.3390/ma15030959 (registering DOI) - 26 Jan 2022
Cited by 3 | Viewed by 2266
Abstract
The adopted TD–GC–MS/O method helps determine the correlation between the odour signals and compounds separated on the chromatographic column, from the analysed gas mixture. It is possible to compare the retention times at which the odour signals were identified with the retention time [...] Read more.
The adopted TD–GC–MS/O method helps determine the correlation between the odour signals and compounds separated on the chromatographic column, from the analysed gas mixture. It is possible to compare the retention times at which the odour signals were identified with the retention time of eluting compounds, when the test system and matrix are known. The presented study describes the details of representative samples obtained from (1) indoor air samples from a room where floor materials containing bitumen are present, (2) wooden floor staves placed in an emission chamber, and (3) fragments (chips) of the materials mentioned above, placed in glass tubes, exposed to an elevated desorption temperature. The results, presented in the paper, describe the identified odours and their intensity and assign chemical compounds to each odour, indicating their likely source of origin. The results presented in the manuscript are intended to show what methodology can be adopted to obtain intense odours from the tested samples, without losing the sensitivity derived from GC–MS. The manuscript presents representative results—case studies. The results for various types of samples were not very reproducible, related to the complex matrix of bituminous products. The enormity of compounds present in tar adhesives makes it possible to indicate only the groups of compounds that emit from these systems. They include, primarily, aliphatic, aromatic and heteroaromatic hydrocarbons, particularly Naphthalene and Phenol derivatives. Full article
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16 pages, 5259 KiB  
Article
Porous ZnCl2-Activated Carbon from Shaddock Peel: Methylene Blue Adsorption Behavior
by Hongxia Zhao, Haihong Zhong, Yu Jiang, Huiyu Li, Pinggui Tang, Dianqing Li and Yongjun Feng
Materials 2022, 15(3), 895; https://doi.org/10.3390/ma15030895 - 25 Jan 2022
Cited by 38 | Viewed by 4573
Abstract
It is of great interest and importance to resource utilization of waste biomass to produce porous carbon for environmental treatments. Pore structure and properties of the obtained carbon mainly relate to carbonization conditions and biomass types. In this work, a series of porous, [...] Read more.
It is of great interest and importance to resource utilization of waste biomass to produce porous carbon for environmental treatments. Pore structure and properties of the obtained carbon mainly relate to carbonization conditions and biomass types. In this work, a series of porous, biomass-activated carbons (AC) were prepared using shaddock peel, with ZnCl2 as a pore-forming agent. The effect of carbonization temperature and the mass ratio between ZnCl2 and shaddock peel were thoroughly investigated. The material composition, surface chemical properties, and surface structures of samples were carefully characterized. The specific surface area and adsorption capacity to methylene blue (MB) of adsorbents were changed with the carbonization temperature and the mass ratios between ZnCl2 and shaddock peel; when the temperature was at 1000 °C and the mass ratio was equal to 2:1, the resulting adsorbent had the largest specific surface area of 2398.74 m2/g and average pore size of 3.04 nm, which showed the highest adsorption capacity to MB to be 869.57 mg/g. The adsorption processes of biomass AC adsorbent matched the pseudo-second-order kinetic model and Langmuir isotherm model. This efficient and environmentally friendly biomass AC adsorbent from shaddock peel, activated by ZnCl2, is a promising candidate for the treatment of water pollution. Full article
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15 pages, 1694 KiB  
Article
Caesium-133 Accumulation by Freshwater Macrophytes: Partitioning of Translocated Ions and Enzyme Activity in Plants and Microorganisms
by Laura Zorza, Maris Bertins, Kristine Saleniece, Gunta Kizane, Andrejs Grinbergs, Ugis Eismonts, Ingars Reinholds, Arturs Viksna and Olga Muter
Sustainability 2022, 14(3), 1132; https://doi.org/10.3390/su14031132 - 19 Jan 2022
Cited by 1 | Viewed by 2016
Abstract
The potential of aquatic plants to accumulate Cs may be of notable importance in the environmental monitoring of radioactive wastes. This study aimed to evaluate the accumulation of Cs-133 by freshwater macrophytes Bacopa amplexicaulis, Elodea densa, Ceratophyllum submersum, and Limnobium [...] Read more.
The potential of aquatic plants to accumulate Cs may be of notable importance in the environmental monitoring of radioactive wastes. This study aimed to evaluate the accumulation of Cs-133 by freshwater macrophytes Bacopa amplexicaulis, Elodea densa, Ceratophyllum submersum, and Limnobium laevigantum after a 10-day incubation period with CsCl (1–1000 μM). The partitioning of Cs and other elements, including 21 metals, such as P, B, and As, was analyzed using inductively coupled plasma mass spectrometry combined with principal component analysis (PCA). The enzymatic activity of plant crude extracts and aquatic microorganisms was characterized. The transfer factor (TF) reached the highest values of 0.13 and 0.10 for C. submersum and L. laevigantum, respectively, at 1000 μM Cs. The TFs in the other sets were below 0.1. In the presence of Cs-133, there was a significant increase in dehydrogenase activity (p < 0.05) and a decrease in the activity of the Folin–Ciocalteu assay. A three-fold decrease in culturable microorganisms was found in plants with 1000 μM Cs. PCA analysis revealed the species-specific elemental distribution in plant biomass and the aquatic phase. A negative correlation between Na, Ca (2.0–2.5, PC1) and Mg, K, and P (−2, PC1) was found. Certain enzyme groups can serve as bioindicators of Cs pollution in aquatic ecosystems. Full article
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16 pages, 3489 KiB  
Article
Physicochemical Characterization of Santa Barbara Amorphous-15 (SBA-15) and Its Functionalization with Polyaniline for Phenol Adsorption
by Lady Johana Cárdenas, Liliana Giraldo and Juan Carlos Moreno-Piraján
Processes 2022, 10(2), 188; https://doi.org/10.3390/pr10020188 - 18 Jan 2022
Cited by 2 | Viewed by 2070
Abstract
The chemical surface of Santa Barbara Amorphous-15 (SBA-15) was functionalized with polyaniline (SBA-15/PA) and was prepared using aniline and ammonium persulfate as the modifying agent and oxidant. The samples were characterized by N2 physical adsorption at 77 K. SBA-15’s surface area was [...] Read more.
The chemical surface of Santa Barbara Amorphous-15 (SBA-15) was functionalized with polyaniline (SBA-15/PA) and was prepared using aniline and ammonium persulfate as the modifying agent and oxidant. The samples were characterized by N2 physical adsorption at 77 K. SBA-15’s surface area was 654.5 m2 g−1, changing to 254.6 m2 g−1. The total acidity and basicity were determined using a modified Boehm’s method, and the point of zero charge pH (pHpzc) was determined. Immersion calorimetry in water, benzene, and NaOH, HCl, and phenol (100 mg L−1) solutions was performed, producing values ranging from −15.1 to −174.1 J g−1 related to the chemical surface, pHpzc, and acid and base group values. Finally, the phenol adsorption capacity was found to be higher for the modified polyaniline silica, at 138 mg g−1. Full article
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16 pages, 3514 KiB  
Article
A Water Surface Contaminants Monitoring Method Based on Airborne Depth Reasoning
by Wei Luo, Wenlong Han, Ping Fu, Huijuan Wang, Yunfeng Zhao, Ke Liu, Yuyan Liu, Zihui Zhao, Mengxu Zhu, Ruopeng Xu and Guosheng Wei
Processes 2022, 10(1), 131; https://doi.org/10.3390/pr10010131 - 10 Jan 2022
Cited by 6 | Viewed by 2198
Abstract
Water surface plastic pollution turns out to be a global issue, having aroused rising attention worldwide. How to monitor water surface plastic waste in real time and accurately collect and analyze the relevant numerical data has become a hotspot in water environment research. [...] Read more.
Water surface plastic pollution turns out to be a global issue, having aroused rising attention worldwide. How to monitor water surface plastic waste in real time and accurately collect and analyze the relevant numerical data has become a hotspot in water environment research. (1) Background: Over the past few years, unmanned aerial vehicles (UAVs) have been progressively adopted to conduct studies on the monitoring of water surface plastic waste. On the whole, the monitored data are stored in the UAVS to be subsequently retrieved and analyzed, thereby probably causing the loss of real-time information and hindering the whole monitoring process from being fully automated. (2) Methods: An investigation was conducted on the relationship, function and relevant mechanism between various types of plastic waste in the water surface system. On that basis, this study built a deep learning-based lightweight water surface plastic waste detection model, which was capable of automatically detecting and locating different water surface plastic waste. Moreover, a UAV platform-based edge computing architecture was built. (3) Results: The delay of return task data and UAV energy consumption were effectively reduced, and computing and network resources were optimally allocated. (4) Conclusions: The UAV platform based on airborne depth reasoning is expected to be the mainstream means of water environment monitoring in the future. Full article
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21 pages, 3996 KiB  
Article
A New Collaborative Multi-Agent Monte Carlo Simulation Model for Spatial Correlation of Air Pollution Global Risk Assessment
by Mustafa Hamid Hassan, Salama A. Mostafa, Aida Mustapha, Mohd Zainuri Saringat, Bander Ali Saleh Al-rimy, Faisal Saeed, A.E.M. Eljialy and Mohammed Ahmed Jubair
Sustainability 2022, 14(1), 510; https://doi.org/10.3390/su14010510 - 4 Jan 2022
Cited by 4 | Viewed by 2368
Abstract
Air pollution risk assessment is complex due to dynamic data change and pollution source distribution. Air quality index concentration level prediction is an effective method of protecting public health by providing the means for an early warning against harmful air pollution. However, air [...] Read more.
Air pollution risk assessment is complex due to dynamic data change and pollution source distribution. Air quality index concentration level prediction is an effective method of protecting public health by providing the means for an early warning against harmful air pollution. However, air quality index-based prediction is challenging as it depends on several complicated factors resulting from dynamic nonlinear air quality time-series data, such as dynamic weather patterns and the verity and distribution of air pollution sources. Subsequently, some minimal models have incorporated a time series-based predicting air quality index at a global level (for a particular city or various cities). These models require interaction between the multiple air pollution sensing sources and additional parameters like wind direction and wind speed. The existing methods in predicting air quality index cannot handle short-term dependencies. These methods also mostly neglect the spatial correlations between the different parameters. Moreover, the assumption of selecting the most recent part of the air quality time series is not valid considering that pollution is cyclic behavior according to various events and conditions due to the high possibility of falling into the trap of local minimum and poor generalization. Therefore, this paper proposes a new air pollution global risk assessment (APGRA) prediction model for an air quality index of spatial correlations to address these issues. The APGRA model incorporates an autoregressive integrated moving average (ARIMA), a Monte Carlo simulation, a collaborative multi-agent system, and a prediction algorithm for reducing air quality index prediction error and processing time. The proposed APGRA model is evaluated based on Malaysia and China real-world air quality datasets. The proposed APGRA model improves the average root mean squared error by 41%, mean and absolute error by 47.10% compared with the conventional ARIMA and ANFIS models. Full article
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17 pages, 5120 KiB  
Article
Analysis of Exhaust Gas Content for Selected Biofuel-Powered Combustion Engines with Simultaneous Modification of Their Controllers
by Marietta Markiewicz, Michał Pająk and Łukasz Muślewski
Materials 2021, 14(24), 7621; https://doi.org/10.3390/ma14247621 - 10 Dec 2021
Cited by 8 | Viewed by 2282
Abstract
The use of renewable resources for powering self-ignition engines in European Union countries involves a high demand for renewable energy which is not accompanied by the development of its production infrastructure. The application of biofuel in vehicle powering is supposed to provide reductions [...] Read more.
The use of renewable resources for powering self-ignition engines in European Union countries involves a high demand for renewable energy which is not accompanied by the development of its production infrastructure. The application of biofuel in vehicle powering is supposed to provide reductions in greenhouse gas emissions and an increase in the share of renewable energy resources in the total energy consumption. The study includes the analyses of power unit exhaust components, such as oxygen, carbon monoxide, nitric oxides, carbonizers, carbon dioxide and a quantity of exhaust particles contained in exhaust gases. Tests using an exhaust gas analyzer and a vapor analyzer were conducted. Three high-pressure engines, characterized by direct fuel injection, were tested. The vehicle computer software adjustments included increasing the fuel dose and the air load. Mixtures of diesel oil and fatty acid methyl esters were used in the tests. Based on the results, a statistical analysis was performed and an assessment model was developed to understand the functioning of the research objects fueled with these mixtures, with simultaneous software changes in the vehicle computers. On the basis of the conducted analysis, it was found that only 30% of fatty acid methyl ester additives to diesel oil reduced the performance parameters of the drive units. Full article
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15 pages, 3981 KiB  
Article
Efficient Removal of Azlocillin Sodium from Water by Polystyrene Anion Exchange Resin Supported MIL-53
by Yi Qian, Haoyan Fu, Long Li, Wenyuan Su, Jiayin Li and Yihao Zhang
Processes 2021, 9(12), 2195; https://doi.org/10.3390/pr9122195 - 6 Dec 2021
Cited by 2 | Viewed by 2967
Abstract
Due to the widespread use of antibiotics in medical treatment, animal husbandry and aquaculture, a large number of antibiotics are discharged into the environment as metabolites or in their original state, causing pollution to water bodies, which is a serious issue. In this [...] Read more.
Due to the widespread use of antibiotics in medical treatment, animal husbandry and aquaculture, a large number of antibiotics are discharged into the environment as metabolites or in their original state, causing pollution to water bodies, which is a serious issue. In this study, a novel nanocomposite adsorbent MIL-53/D201 was successfully prepared by hydrothermal synthesis. This approach overcomes the disadvantage of easy dissociation of MOF material in the water phase and realizes the efficient removal of antibiotic azlocillin sodium in water. The crystal morphology and basic structure of the composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy scattering spectroscopy (EDS), and specific surface area and porosity analyzer (BET). The results showed that MIL-53 was successfully synthesized in situ in D201. The results of adsorption experiments show that the maximum saturated adsorption capacity of the composite is 122.3 mg/g when the dosage of the composite is 1.0 g/L. Compared with pure MIL-53 material, the composite material exhibits greater stability and efficient adsorption performance for target pollutants at different pH values. The adsorption process accords with the quasi-second-order kinetic adsorption model and Langmuir adsorption isothermal model. After five cycles of adsorption and desorption, the removal rate of MIL-53/D201 to azlocillin sodium was still above 87%. Full article
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13 pages, 3933 KiB  
Article
Microdome-Tunable Graphene/Carbon Nanotubes Pressure Sensors Based on Polystyrene Array for Wearable Electronics
by Xingjie Su, Chunli Luo, Weiguo Yan, Junyi Jiao and Dongzhou Zhong
Materials 2021, 14(23), 7385; https://doi.org/10.3390/ma14237385 - 2 Dec 2021
Cited by 13 | Viewed by 2542
Abstract
Resistive pressure sensors are appealing due to having several advantages, such as simple reading mechanisms, simple construction, and quick dynamic response. Achieving a constantly changeable microstructure of sensing materials is critical for the flexible pressure sensor and remains a difficulty. Herein, a flexible, [...] Read more.
Resistive pressure sensors are appealing due to having several advantages, such as simple reading mechanisms, simple construction, and quick dynamic response. Achieving a constantly changeable microstructure of sensing materials is critical for the flexible pressure sensor and remains a difficulty. Herein, a flexible, tunable resistive pressure sensors is developed via simple, low-cost microsphere self-assembly and graphene/carbon nanotubes (CNTs) solution drop coating. The sensor uses polystyrene (PS) microspheres to construct an interlocked dome microstructure with graphene/CNTs as a conductive filler. The results indicate that the interlocked microdome-type pressure sensor has better sensitivity than the single microdome-type and single planar-type without surface microstructure. The pressure sensor’s sensitivity can be adjusted by varying the diameter of PS microspheres. In addition, the resistance of the sensor is also tunable by adjusting the number of graphene/CNT conductive coating layers. The developed flexible pressure sensor effectively detected human finger bending, demonstrating tremendous potential in human motion monitoring. Full article
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27 pages, 12215 KiB  
Article
Carbon Dioxide Separation by Polyethylene Glycol and Glutamic Acid/Polyvinyl Alcohol Composite Membrane
by Angus Shiue, Ming-Jie Yin, Min-Hsuan Tsai, Shu-Mei Chang and Graham Leggett
Sustainability 2021, 13(23), 13367; https://doi.org/10.3390/su132313367 - 2 Dec 2021
Cited by 6 | Viewed by 2567
Abstract
In this study, Polyvinyl alcohol (PVA) blended with Polyethylene glycol (PEG), Monosodium glutamate (MSG) and Glutamic acid (GA) was cast on a reverse osmosis membrane to form a composite membrane. It is expected that the ether group can increase the CO2 affinity [...] Read more.
In this study, Polyvinyl alcohol (PVA) blended with Polyethylene glycol (PEG), Monosodium glutamate (MSG) and Glutamic acid (GA) was cast on a reverse osmosis membrane to form a composite membrane. It is expected that the ether group can increase the CO2 affinity of the membrane. Sodium tetraborate (Borax) as a crosslinker can increase membrane basicity and glutamic acid (salt) can provide an enhanced transport mechanism, thereby improving the permeability and selectivity of carbon dioxide. FTIR spectra show that the thickness of coating is sufficiently low, while SEM results show that PVA-PEG series have a dense surface, and particles are observed on the surface of MSG/GA series. The gas permeance and separation performance of the composite membrane was tested using a single gas. Results showed that CO2 had higher permeance (GPU) at lower pressure differential. PEG with an ether group had the greatest effect on improving CO2 permeance and selectivity. However, MSG and GA with amine groups could not effectively improve CO2 selectivity due to solubility. The best coating solution was provided by PVA-PEG-1.2. The CO2 selectivity of the composite membrane was 10.05 with a pressure differential of 1.00 bar in a humid environment and no obvious deterioration was observed over a 10-day period. Borax can improve selectivity, water absorption, and thermal stability while avoiding the need for high temperature and long crosslinking time of aldehydes, which makes it possible to be used in a PVA carbon dioxide separation membrane. Full article
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11 pages, 2212 KiB  
Article
Unstimulated Parotid Saliva Is a Better Method for Blood Glucose Prediction
by Yangyang Cui, Hankun Zhang, Jia Zhu, Lu Peng, Zhili Duan, Tian Liu, Jiasheng Zuo, Lu Xing, Zhenhua Liao, Song Wang and Weiqiang Liu
Appl. Sci. 2021, 11(23), 11367; https://doi.org/10.3390/app112311367 - 1 Dec 2021
Cited by 16 | Viewed by 3655
Abstract
Objective: Saliva glucose has been widely used in diagnosing and monitoring diabetes, but the saliva collection method will affect saliva glucose concentration. So, this study aims to identify the ideal saliva collection method. Method: A total amount of six saliva collection methods were [...] Read more.
Objective: Saliva glucose has been widely used in diagnosing and monitoring diabetes, but the saliva collection method will affect saliva glucose concentration. So, this study aims to identify the ideal saliva collection method. Method: A total amount of six saliva collection methods were employed in 80 healthy participants in the morning. Besides, three unstimulated saliva methods were employed in another 30 healthy participants in the morning; in the meantime the blood glucose of these 30 participants was detected with a Roche blood glucose meter. The glucose oxidase method with 2, 4, 6-tribromo-3-hydroxybenzoic acid (TBHBA) as the chromogen has been improved to be suitable for healthy people, through the selection of the optimal pH value and ionic strength of the reaction system. This method was used for the detection of saliva glucose. Results: The improved method obtained absorbance at the wavelength of 520 nm, and the optimized parameter combination was pH 6.5 and 5 mg/dL NaCl. The lower limit of glucose detection was 0.1 mg/dL. Unstimulated saliva glucose concentration was higher than stimulated saliva glucose concentration. Unstimulated parotid saliva glucose concentration was the highest. Besides, unstimulated saliva glucose has a better normal distribution effect. Meantime, it was found that unstimulated parotid saliva was the most highly correlated with blood glucose (R2 = 0.707). Conclusions: the saliva collection method was an important factor that affected saliva glucose concentration. Unstimulated parotid saliva was the most highly correlated with blood glucose, which provided a reference for prediction of diabetes mellitus. Full article
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15 pages, 3765 KiB  
Article
Preparation of Polystyrene Microsphere-Templated Porous Monolith for Wastewater Filtration
by Nur Faezah Ibadat, Suryani Saallah, Clarence M. Ongkudon and Mailin Misson
Materials 2021, 14(23), 7165; https://doi.org/10.3390/ma14237165 - 25 Nov 2021
Cited by 1 | Viewed by 2795
Abstract
Porous monoliths prepared using templates are highly sought after for filtration applications due to their good mass transport properties and high permeability. Current templates, however, often lead to the formation of dead-end pores and irregular pore distributions, which reduce the efficiency of the [...] Read more.
Porous monoliths prepared using templates are highly sought after for filtration applications due to their good mass transport properties and high permeability. Current templates, however, often lead to the formation of dead-end pores and irregular pore distributions, which reduce the efficiency of the substrate flow across the monolith column. This study focused on the preparation of a microsphere-templated porous monolith for wastewater filtration. The optimal template/monomer ratio (50:50, 60:40, 70:30) was determined, and appropriate template removal techniques were assessed for the formation of homogenous pores. The physicochemical characteristics and pore homogeneity of the monoliths were examined. The 60:40 ratio was determined to result in monoliths with homogeneous pore distributions ranging from 1.9 μm to 2.3 μm. SEM and FTIR investigations revealed that solvent treatment was effective for removing templates from the resulting solid monolith. The water quality assessments revealed reductions in the turbidity and the total number of suspended particles in the tested wastewater of up to 96–99%. The findings of this study provide insightful knowledge regarding the fabrication of monoliths with homogenous pores that are beneficial for wastewater treatment. Full article
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18 pages, 8652 KiB  
Article
Study on the Mechanical and Leaching Characteristics of Permeable Reactive Barrier Waste Solidified by Cement-Based Materials
by Xuan Chen, Wenkui Feng, Hao Wen, Wei Duan, Chongxian Suo, Mingxing Xie and Xiaoqiang Dong
Materials 2021, 14(22), 6985; https://doi.org/10.3390/ma14226985 - 18 Nov 2021
Cited by 4 | Viewed by 1777
Abstract
The durability against wet-dry (w-d) cycles is an important parameter for the service life design of solidified permeable reactive barrier (PRB) waste. This study introduces the potential use of cement, fly ash, and carbide slag (CFC) for the stabilization/solidification (S/S) of PRB waste. [...] Read more.
The durability against wet-dry (w-d) cycles is an important parameter for the service life design of solidified permeable reactive barrier (PRB) waste. This study introduces the potential use of cement, fly ash, and carbide slag (CFC) for the stabilization/solidification (S/S) of PRB waste. In this study, solidified PRB waste was subjected to different w-d cycles ranging in times from 0 to 10. By analyzing the mass loss, the unconfined compressive strength (UCS), initial resistivity (IR), and the Mn2+ leaching concentration under different durability conditions, the results demonstrate that these variables increased and then tended to decrease with the number of w-d cycles. The UCS of contaminated soil is significantly correlated with IR. Moreover, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses indicate that the hydration products calcium silicate hydrate (C-S-H) and ettringite (AFt) are the main reasons for the enhancement of the UCS. However, the increase in Mn2+ concentration leads to a decrease in hydration products and the compactness of solidified soil, which has negative effects for the UCS and the leaching ion concentration. In general, the durability exhibited by the PRB waste treated with S/S in this paper was satisfactory. This study can provide theoretical guidance for practical engineering applications. Full article
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10 pages, 1892 KiB  
Article
Smartphone-Based Colorimetric Detection of Chromium (VI) by Maleic Acid-Functionalized Gold Nanoparticles
by Ahmed Mohamed, Xuemeng Li, Chengfei Li, Xuegang Li, Chao Yuan and Hassan Barakat
Appl. Sci. 2021, 11(22), 10894; https://doi.org/10.3390/app112210894 - 18 Nov 2021
Cited by 10 | Viewed by 2463
Abstract
Because of the significant environmental pollution produced by human activities, there is an ongoing need to develop transportable, simple, and reliable techniques for determining trace contaminants on the spot. This work reported a colorimetric detection method for aqueous Cr(VI) sensing by maleic acid-functionalized [...] Read more.
Because of the significant environmental pollution produced by human activities, there is an ongoing need to develop transportable, simple, and reliable techniques for determining trace contaminants on the spot. This work reported a colorimetric detection method for aqueous Cr(VI) sensing by maleic acid-functionalized gold nanoparticles with high sensitivity and selectivity. The wine-red color of the probe solution can change to gray even in the presence of 1.0 µg L−1 of aqueous Cr(VI). Moreover, with the assistance of a smartphone installed with a commercially available color scan application software, its concentration of could be readily quantified on the spot without the help of UV-Vis spectrometer. The detection limit could reach as low as 0.1 µg L−1 with linear range from 0.2 to 2.0 µg L−1. Most importantly, the coefficient variation of the proposed smartphone-based method was equivalent to that of colorimetry, demonstrating the high accuracy of the proposed method for accurate detection of Cr(VI) in resource-constrained countries. Conclusively, with the help of the smartphone, this nanomaterials-based probe demonstrated the potential in the field of environment monitoring for on-site quantitative detection of any pollutants in resource-constrained countries. Full article
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17 pages, 2911 KiB  
Review
Removal of Toxic Heavy Metals from Contaminated Aqueous Solutions Using Seaweeds: A Review
by Edward Hingha Foday Jr, Bai Bo and Xiaohui Xu
Sustainability 2021, 13(21), 12311; https://doi.org/10.3390/su132112311 - 8 Nov 2021
Cited by 27 | Viewed by 6541
Abstract
Heavy metal contamination affects lives with concomitant environmental pollution, and seaweed has emerged as a remedy with the ability to save the ecosystem, due to its eco-friendliness, affordability, availability, and effective metal ion removal rate. Heavy metals are intrinsic toxicants that are known [...] Read more.
Heavy metal contamination affects lives with concomitant environmental pollution, and seaweed has emerged as a remedy with the ability to save the ecosystem, due to its eco-friendliness, affordability, availability, and effective metal ion removal rate. Heavy metals are intrinsic toxicants that are known to induce damage to multiple organs, especially when subjected to excess exposure. With respect to these growing concerns, this review presents the preferred sorption material among the many natural sorption materials. The use of seaweeds to treat contaminated solutions has demonstrated outstanding results when compared to other materials. The sorption of metal ions using dead seaweed biomass offers a comparative advantage over other natural sorption materials. This article summarizes the impact of heavy metals on the environment, and why dead seaweed biomass is regarded as the leading remediation material among the available materials. This article also showcases the biosorption mechanism of dead seaweed biomass and its effectiveness as a useful, cheap, and affordable bioremediation material. Full article
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16 pages, 42344 KiB  
Article
Development of Flotation Device for Removing Unburnt Carbon in Fly Ash for Use in Hardened Cementitious Materials
by Hangwei Lin, Koji Takasu, Hidehiro Koyamada and Hiroki Suyama
Materials 2021, 14(21), 6517; https://doi.org/10.3390/ma14216517 - 29 Oct 2021
Cited by 5 | Viewed by 2137
Abstract
The unburned carbon in fly ash inhibits the performance of concrete. A device using the flotation method to remove unburned carbon in fly ash was developed, and the operating condition of the device was experimentally examined. According to the results, the device was [...] Read more.
The unburned carbon in fly ash inhibits the performance of concrete. A device using the flotation method to remove unburned carbon in fly ash was developed, and the operating condition of the device was experimentally examined. According to the results, the device was able to remove unburnt carbon from fly ash by using the installed micro bubble nozzles and a whirl-type pump. The removal efficiency of unburnt carbon improved when prior forced stirring was carried out by a concrete mixer for 3 min, and a scavenger was added into the fly ash slurry at a density of about 60 wt%. It has also been confirmed that the method of circulating water is more effective than the method of not circulating water. The elements of the modified fly ash slurry (MFAS) have also been experimentally confirmed as not being too different from untreated fly ash, except for the fact that the content of unburned carbon is reduced. The compressive strength and drying shrinkage characteristics of concrete made with MFAS were investigated. The use of MFAS will reduce the performance of concrete compared to that of ordinary concrete. This shows that in a certain range (15–30%), the influence of MFAS on drying shrinkage is constant. The static elastic modulus and dynamic elastic modulus were also investigated. The above results show that the application of MFAS prepared by the flotation method to concrete is feasible. Full article
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13 pages, 5683 KiB  
Article
Black Talc-Based TiO2/ZnO Composite for Enhanced UV-Vis Photocatalysis Performance
by Huan Shuai, Jiao Wang, Xianguang Wang and Gaoxiang Du
Materials 2021, 14(21), 6474; https://doi.org/10.3390/ma14216474 - 28 Oct 2021
Cited by 9 | Viewed by 2110
Abstract
Herein, using black talc as a carrier, a ternary black talc-TiO2/ZnO composite photocatalyst was prepared by the sol-gel method, and the effect of the black talc on the hetero-structure properties of the TiO2 and ZnO was systematically studied. The prepared [...] Read more.
Herein, using black talc as a carrier, a ternary black talc-TiO2/ZnO composite photocatalyst was prepared by the sol-gel method, and the effect of the black talc on the hetero-structure properties of the TiO2 and ZnO was systematically studied. The prepared composite photocatalyst showed an excellent degradation performance of the pollutant, where black talc plays an important role in promoting the interface interaction by enhancing the contact area between the TiO2 and ZnO. Moreover, the free carbon element doping in black talc favors the formation of more oxygen vacancies, thereby improving the response as a photocatalyst in visible light. In addition, the carbon in the black talc can also adsorb organic pollutants and enrich the surroundings of the photocatalyst with pollutants, so it further improves the catalytic efficiency of the photocatalyst. Under UV irradiation, the degradation rate of Rhodamine B on black talc-TiO2/ZnO was found 3.3 times higher than that of black talc-TiO2 with good stability. Full article
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12 pages, 4277 KiB  
Article
Construction of BiOCl/Clinoptilolite Composite Photocatalyst for Boosting Formaldehyde Removal
by Yonghao Di, Xiangwei Zhang, Xinlin Wang and Shuilin Zheng
Materials 2021, 14(21), 6469; https://doi.org/10.3390/ma14216469 - 28 Oct 2021
Cited by 3 | Viewed by 2138
Abstract
Binary composite was synthesized via coupling BiOCl with alkali leached natural clinoptilolite (40B0/CN), which showed retarded recombination of photo-generated carriers. The clinoptilolite was pretreated with alkali leaching, resulting in a larger pore size and high cation exchange capacity. The modified clinoptilolite was more [...] Read more.
Binary composite was synthesized via coupling BiOCl with alkali leached natural clinoptilolite (40B0/CN), which showed retarded recombination of photo-generated carriers. The clinoptilolite was pretreated with alkali leaching, resulting in a larger pore size and high cation exchange capacity. The modified clinoptilolite was more feasible for the growth of BiOCl and to promote the adsorption ability for formaldehyde (HCHO). In addition, the cation exchange capacity was conducive to anchor Bi3+, further leading to the reduction of the particle size of BiOCl. The carrier effect of alkali leached natural clinoptilolite promoted the amorphous transformation of BiOCl at low temperature, which simultaneously produced more distortions and defects in the BiOCl lattice. The 40B0/CN composite exhibited the superior light absorption ability with a narrower band gap. The photocatalytic degradation rate for HCHO of 40B0/CN under solar light reached 87.7%, and the reaction rate constant was 0.0166 min−1, which was 1.6 times higher than that of BiOCl. This paper gave a deep insight into photocatalytic technology to efficiently degrade formaldehyde. Full article
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13 pages, 2896 KiB  
Article
Fast and Efficient Removal of Uranium onto a Magnetic Hydroxyapatite Composite: Mechanism and Process Evaluation
by Tao Ou, Hairong Peng, Minhua Su, Qingpu Shi, Jinfeng Tang, Nan Chen and Diyun Chen
Processes 2021, 9(11), 1927; https://doi.org/10.3390/pr9111927 - 28 Oct 2021
Cited by 10 | Viewed by 2099
Abstract
The exploration and rational design of easily separable and highly efficient sorbents with satisfactory capability of extracting radioactive uranium (U)-containing compound(s) are of paramount significance. In this study, a novel magnetic hydroxyapatite (HAP) composite (HAP@ CoFe2O4), which was coupled [...] Read more.
The exploration and rational design of easily separable and highly efficient sorbents with satisfactory capability of extracting radioactive uranium (U)-containing compound(s) are of paramount significance. In this study, a novel magnetic hydroxyapatite (HAP) composite (HAP@ CoFe2O4), which was coupled with cobalt ferrite (CoFe2O4), was rationally designed for uranium(VI) removal through a facile hydrothermal process. The U(VI) ions were rapidly removed using HAP@ CoFe2O4 within a short time (i.e., 10 min), and a maximum U(VI) removal efficiency of 93.7% was achieved. The maximum adsorption capacity (Qmax) of the HAP@CoFe2O4 was 338 mg/g, which demonstrated the potential of as-prepared HAP@CoFe2O4 in the purification of U(VI) ions from nuclear effluents. Autunite [Ca(UO2)2(PO4)2(H2O)6] was the main crystalline phase to retain uranium, wherein U(VI) was effectively extracted and immobilized in terms of a relatively stable mineral. Furthermore, the reacted HAP@CoFe2O4 can be magnetically recycled. The results of this study reveal that the suggested process using HAP@CoFe2O4 is a promising approach for the removal and immobilization of U(VI) released from nuclear effluents. Full article
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16 pages, 5146 KiB  
Article
Synthesis of ZnO-CuO and ZnO-Co3O4 Materials with Three-Dimensionally Ordered Macroporous Structure and Its H2S Removal Performance at Low-Temperature
by Tao Yu, Zhuo Chen, Yundong Wang and Jianhong Xu
Processes 2021, 9(11), 1925; https://doi.org/10.3390/pr9111925 - 27 Oct 2021
Cited by 6 | Viewed by 2473
Abstract
H2S is a common but hazardous impurity in syngas, biogas, or natural gas. For some advanced power generation technologies, such as integrated gasification combined cycle (IGCC), solid oxide fuel cells, H2S content needs to be reduced to an acceptable [...] Read more.
H2S is a common but hazardous impurity in syngas, biogas, or natural gas. For some advanced power generation technologies, such as integrated gasification combined cycle (IGCC), solid oxide fuel cells, H2S content needs to be reduced to an acceptable level. In this work, a series of highly porous Zn-Cu and Zn-Co composites with three-dimensionally ordered macropores (3DOM) structure were synthesized via the colloidal crystal template method and used to remove H2S at 150 °C and one atm. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption studies, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were carried out to analyze the fresh and spent adsorbents. The results show that all the adsorbents possess well-ordered macropores, a large surface area, and a highly dispersed active phase. The relative content of Zn and (Cu or Co) has a significant influence on the desulfurization performance of adsorbents. The addition of CuO significantly increases the sulfur capacity and 3DOM-Zn0.5Cu0.5 shows the largest sulfur capacity of all the adsorbents, reaching up to 102.5 mg/g. The multiple adsorption/regeneration cycles of 3DOM-Zn0.5Cu0.5 and 3DOM-Zn0.5Co0.5 indicate that the as-prepared adsorbents are stable, and the sulfur capacity can still exceed 65% of the fresh adsorbents after six cycles. Full article
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13 pages, 6709 KiB  
Article
An Acylhydrazone-Based Fluorescent Sensor for Sequential Recognition of Al3+ and H2PO4
by Donghwan Choe and Cheal Kim
Materials 2021, 14(21), 6392; https://doi.org/10.3390/ma14216392 - 25 Oct 2021
Cited by 9 | Viewed by 2260
Abstract
A novel acylhydrazone-based fluorescent sensor NATB was designed and synthesized for consecutive sensing of Al3+ and H2PO4. NATB displayed fluorometric sensing to Al3+ and could sequentially detect H2PO4 by fluorescence quenching. The [...] Read more.
A novel acylhydrazone-based fluorescent sensor NATB was designed and synthesized for consecutive sensing of Al3+ and H2PO4. NATB displayed fluorometric sensing to Al3+ and could sequentially detect H2PO4 by fluorescence quenching. The limits of detection for Al3+ and H2PO4 were determined to be 0.83 and 1.7 μM, respectively. The binding ratios of NATB to Al3+ and NATB-Al3+ to H2PO4 were found to be 1:1. The sequential recognition of Al3+ and H2PO4 by NATB could be repeated consecutively. In addition, the practicality of NATB was confirmed with the application of test strips. The sensing mechanisms of Al3+ and H2PO4 by NATB were investigated through fluorescence and UV–Visible spectroscopy, Job plot, ESI-MS, 1H NMR titration, and DFT calculations. Full article
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27 pages, 12067 KiB  
Article
Activated Graphene Oxide-Calcium Alginate Beads for Adsorption of Methylene Blue and Pharmaceuticals
by Burcu Gunes, Yannick Jaquet, Laura Sánchez, Rebecca Pumarino, Declan McGlade, Brid Quilty, Anne Morrissey, Zahra Gholamvand, Kieran Nolan and Jenny Lawler
Materials 2021, 14(21), 6343; https://doi.org/10.3390/ma14216343 - 23 Oct 2021
Cited by 14 | Viewed by 3693
Abstract
The remarkable adsorption capacity of graphene-derived materials has prompted their examination in composite materials suitable for deployment in treatment of contaminated waters. In this study, crosslinked calcium alginate–graphene oxide beads were prepared and activated by exposure to pH 4 by using 0.1M HCl. [...] Read more.
The remarkable adsorption capacity of graphene-derived materials has prompted their examination in composite materials suitable for deployment in treatment of contaminated waters. In this study, crosslinked calcium alginate–graphene oxide beads were prepared and activated by exposure to pH 4 by using 0.1M HCl. The activated beads were investigated as novel adsorbents for the removal of organic pollutants (methylene blue dye and the pharmaceuticals famotidine and diclofenac) with a range of physicochemical properties. The effects of initial pollutant concentration, temperature, pH, and adsorbent dose were investigated, and kinetic models were examined for fit to the data. The maximum adsorption capacities qmax obtained were 1334, 35.50 and 36.35 mg g−1 for the uptake of methylene blue, famotidine and diclofenac, respectively. The equilibrium adsorption had an alignment with Langmuir isotherms, while the kinetics were most accurately modelled using pseudo- first-order and second order models according to the regression analysis. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated and the adsorption process was determined to be exothermic and spontaneous. Full article
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12 pages, 5619 KiB  
Article
Preparation of TiO2/Black Talc Composite Photocatalyst and the Research on Its Adsorption-Degradation Coupling Effects
by Huan Shuai, Yuxin Wang, Jiao Wang, Gaoxiang Du, Daimei Chen and Yu Liang
Materials 2021, 14(20), 6038; https://doi.org/10.3390/ma14206038 - 13 Oct 2021
Cited by 1 | Viewed by 2068
Abstract
In this paper, a TiO2/black talc composite photocatalyst was prepared by the sol-gel method using TBOT as titanium source and black talc as carrier. Rhodamine B was used as the targeted pollutant to study the adsorption role of carbon in black [...] Read more.
In this paper, a TiO2/black talc composite photocatalyst was prepared by the sol-gel method using TBOT as titanium source and black talc as carrier. Rhodamine B was used as the targeted pollutant to study the adsorption role of carbon in black talc. The results showed that with the adsorption-degradation cycles, the illumination time can be reduced by 40%. The adsorption rate and degradation rate of the composite photocatalyst was also increased. The degradation rate of Rhodamine B reached more than 95%, which fully shows the synergistic effect between TiO2 nanoparticles and black talc. In this way, the adsorption-degradation coupling of the photocatalyst could be realized. Full article
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9 pages, 263 KiB  
Article
A Small-Scale Study on Removal of Heavy Metals from Contaminated Water Using Water Hyacinth
by An The Huynh, Yi-Ching Chen and Bich Ngoc Thi Tran
Processes 2021, 9(10), 1802; https://doi.org/10.3390/pr9101802 - 11 Oct 2021
Cited by 30 | Viewed by 11078
Abstract
The aim of this research was to determine whether water hyacinth can be used to remove heavy metals, such as cadmium, arsenic, lead, zinc, and copper, from industrial wastewater. Investigations of the pollution removal or prevention potential of aquatic macrophytes, such as heavy [...] Read more.
The aim of this research was to determine whether water hyacinth can be used to remove heavy metals, such as cadmium, arsenic, lead, zinc, and copper, from industrial wastewater. Investigations of the pollution removal or prevention potential of aquatic macrophytes, such as heavy metal bio-indicators in aquatic habitats, can prove to be advanced field studies. Water hyacinth is one of the aquatic plant species that has been effectively utilized for the treatment of wastewater. It is extremely effective in removing stains, suspended solids, BOD, organic matter, and heavy metals. This research focused on the use of water hyacinth to treat wastewater from heavy metals. Water hyacinths can grow in sewage, absorbing and digesting contaminants and transforming sewage effluents into comparatively clean water in the process. As a result, the plants have the potential to be used as natural water purification systems at a fraction of the cost of a standard sewage treatment facility. The experiment was performed using healthy, young, and acclimatized water hyacinths. Containment water with a cadmium concentration of 0.5 mg/L, arsenic concentration of 0.5 mg/L, lead concentration of 2 mg/L, zinc concentration of 5 mg/L, and copper concentration of 5 mg/L was added to five different polyethylene pots with 100 g of water hyacinth in each pot. After 30 days, the removal efficiency for heavy metals (Cd, As, Pb, Zn, and Cu) reached 59–92%, and the results were within the permitted limits according to the National Technical Regulation on Industrial Wastewater in Vietnam. Based on this information, it is possible to deduce that water hyacinth can be utilized to remove cadmium, arsenic, lead, zinc, and copper from industrial wastewater effluents efficiently. Full article
17 pages, 7419 KiB  
Article
Research on the Preparation Parameters and Basic Properties of Premelted Calcium Aluminate Slag Prepared from Secondary Aluminum Dross
by Shaoyan Hu, Deyong Wang, Dong Hou, Wei Zhao, Xianglong Li, Tianpeng Qu and Qingde Zhu
Materials 2021, 14(19), 5855; https://doi.org/10.3390/ma14195855 - 6 Oct 2021
Cited by 16 | Viewed by 2560
Abstract
Secondary aluminum dross is a byproduct of the electrolytic aluminum industry, whose main components are Al2O3, AlN and Na3AlF6. Secondary aluminum dross is a type of hazardous waste, with a tremendous yield every year. Realizing [...] Read more.
Secondary aluminum dross is a byproduct of the electrolytic aluminum industry, whose main components are Al2O3, AlN and Na3AlF6. Secondary aluminum dross is a type of hazardous waste, with a tremendous yield every year. Realizing the harmless treatment or resource utilization of secondary aluminum dross has important economic and social benefits. In the present research, the process of preparing premelted calcium aluminate slag used for molten steel refining from secondary aluminum dross was studied in detail. Firstly, the chemical composition and phase component of secondary aluminum dross were analyzed systematically. Then, according to phase diagram analysis and melting point measurement, the appropriate mixing ratio of CaO and secondary aluminum dross and the appropriate calcination temperature were determined. On this basis, an experiment of premelted calcium aluminate slag preparation was carried out in a tubular resistance furnace. The phase component and micromorphology of the premelted slag were analyzed by XRD and SEM. The results show that the main component of the premelted calcium aluminate slag is 11CaO·7Al2O3·CaF2 phase with a low melting point. The original Na3AlF6 phase, which is the cause of leachable fluoride in secondary aluminum dross, disappears totally, and there is no water-soluble fluoride detected in the leaching toxicity detection. The research indicates that the process of preparing premelted calcium slag from secondary aluminum dross is feasible, which provides a helpful reference for the resource utilization of secondary aluminum dross. Full article
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15 pages, 4439 KiB  
Article
Factors Affecting Carbonation Depth in Foamed Concrete Bricks for Accelerate CO2 Sequestration
by Abdullah Faisal Alshalif, J. M. Irwan, Husnul Azan Tajarudin, N. Othman, A. A. Al-Gheethi, S. Shamsudin, Wahid Ali Hamood Altowayti and Saddam Abo Sabah
Sustainability 2021, 13(19), 10999; https://doi.org/10.3390/su131910999 - 4 Oct 2021
Cited by 8 | Viewed by 2317
Abstract
Foamed concrete bricks (FCB) have high levels of porosity to sequestrate atmospheric CO2 in the form of calcium carbonate CaCO3 via acceleration of carbonation depth. The effect of density and curing conditions on CO2 sequestration in FCB was investigated in [...] Read more.
Foamed concrete bricks (FCB) have high levels of porosity to sequestrate atmospheric CO2 in the form of calcium carbonate CaCO3 via acceleration of carbonation depth. The effect of density and curing conditions on CO2 sequestration in FCB was investigated in this research to optimize carbonation depth. Statistical analysis using 2k factorial and response surface methodology (RSM) comprising 11 runs and eight additional runs was used to optimize the carbonation depth of FCB for 28 days (d). The main factors selected for the carbonation studies include density, temperature and CO2 concentration. The curing of the FCB was performed in the chamber. The results indicated that all factors significantly affected the carbonation depth of FCB. The optimum carbonation depth was 9.7 mm, which was determined at conditions; 1300 kg/m3, 40 °C, and 20% of CO2 concentration after 28 d. Analysis of variance (ANOVA) and residual plots demonstrated the accuracy of the regression equation with a predicted R2 of 89.43%, which confirms the reliability of the predicted model. Full article
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15 pages, 1724 KiB  
Review
Sewage Sludge as Inhibitor of the Formation of Persistent Organic Pollutants during Incineration
by Juan A. Conesa
Sustainability 2021, 13(19), 10935; https://doi.org/10.3390/su131910935 - 1 Oct 2021
Cited by 8 | Viewed by 2533
Abstract
With the objective of suppressing dioxins and furans (PCDD/Fs) emission in municipal solid waste incineration plants (MSWI), different chemical inhibitors have been tested. Among these inhibitors, nitrogen and sulphur compounds can significantly suppress PCDD/Fs formation via de novo synthesis, which gives very interesting [...] Read more.
With the objective of suppressing dioxins and furans (PCDD/Fs) emission in municipal solid waste incineration plants (MSWI), different chemical inhibitors have been tested. Among these inhibitors, nitrogen and sulphur compounds can significantly suppress PCDD/Fs formation via de novo synthesis, which gives very interesting results with very little capital investment. In recent years, the possibility of using waste rich in nitrogen and/or sulphur as a source of inhibitor compounds has been considered, and thus has reduced the emissions of pollutants while the waste is treated. The effect of adding sludge from urban sewage treatment plants in three variants has been specially studied: directly mixing the waste, using the decomposition gas of the previously dried sludge, and using the decomposition gas of the sludge together with other inhibitors such as thiourea. Reduction of emissions in laboratory tests using model samples indicated the efficiency to be higher than 99%, using sewage sludge (SS) as an inhibitor whereas, in actual MSWI plants, the efficiency can be as high as 90%. Full article
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15 pages, 3201 KiB  
Article
Decolourisation and Biodegradation of Textile Di-azo Dye Congo Red by Chryseobacterium geocarposphaerae DD3
by Shrabana Sarkar, Alex Echeverría-Vega, Aparna Banerjee and Rajib Bandopadhyay
Sustainability 2021, 13(19), 10850; https://doi.org/10.3390/su131910850 - 29 Sep 2021
Cited by 15 | Viewed by 3814
Abstract
In the present study, Chryseobacterium geocarposphaerae DD3 isolated from textile industry dye effluent in West Bengal, India, displayed significant tolerance to sulfonated di-azo dye Congo red (CR), up to 500 ppm. The optimum decolourisation revealed that C. geocarposphaerae DD3 was capable of 96.52% [...] Read more.
In the present study, Chryseobacterium geocarposphaerae DD3 isolated from textile industry dye effluent in West Bengal, India, displayed significant tolerance to sulfonated di-azo dye Congo red (CR), up to 500 ppm. The optimum decolourisation revealed that C. geocarposphaerae DD3 was capable of 96.52% decolourisation of 0.2 g L−1 CR within 12 h of treatment in the presence of 5 g L−1 glucose as supplementary carbon source. Biodegradation analysis of decolourised CR containing water was investigated by FTIR, MS and 1H NMR, which confirmed the absence of azo bond as well as the toxic aromatic amines. Further, phytotoxicity analysis was performed to assess the toxicity of CR before and after bacterial treatment. Growth indexes of Vigna radiata L. seed confirmed that the biodegraded water was non-phytotoxic in comparison to the control CR solution. Multivariate analyses confirmed the same, showing significant differences between measured plant health indicators for CR solutions, whereas no significant differences were found between distilled and treated water. This study is novel as it is the first report of dye degradation by C. geocarposphaerae and may lead to a sustainable way of treating dye-contaminated water in the near future. Full article
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14 pages, 3682 KiB  
Article
Performance of Plain Concrete and Cement Blocks with Cement Partially Replaced by Cement Kiln Dust
by Yasir M. Alharthi, Ahmed S. Elamary and Waleed Abo-El-Wafa
Materials 2021, 14(19), 5647; https://doi.org/10.3390/ma14195647 - 28 Sep 2021
Cited by 11 | Viewed by 2257
Abstract
The growth of the construction industry has led to the greater consumption of natural resources, which has a direct or indirect negative impact on the environment. To mitigate this, recycled or waste materials are being used as a partial substitute in the manufacture [...] Read more.
The growth of the construction industry has led to the greater consumption of natural resources, which has a direct or indirect negative impact on the environment. To mitigate this, recycled or waste materials are being used as a partial substitute in the manufacture of concrete. Among these waste materials is cement kiln dust (CKD), which is produced during cement production. This study investigated the potential benefits of replacing part of the cement with CKD in two construction applications, i.e., plain concrete and cement blocks. This reflects positively on cost, energy, and the environment, since putting CKD in a landfill damages agricultural soil and plant respiration. In this study, an experimental program was carried out to study how replacing various percentages of ordinary portland cement (OPC) with CKD affected the compressive strengths, the tensile strengths, and the air contents of concrete and cement blocks. Although the results showed that the compressive and tensile strengths decreased as the amount of CKD increased, the air content of the concrete increased, which showed that 5% CKD was suitable for such applications. The results were used to propose two equations that approximate the concrete and cement block compressive strengths according to the CKD replacement percentage. Full article
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17 pages, 3473 KiB  
Article
Using Statistical Modeling for Assessing Lettuce Crops Contaminated with Zn, Correlating Plants Growth Characteristics with the Soil Contamination Levels
by Petru Cardei, Florin Nenciu, Nicoleta Ungureanu, Mirabela Augustina Pruteanu, Valentin Vlăduț, Dan Cujbescu, Iuliana Găgeanu and Oana Diana Cristea
Appl. Sci. 2021, 11(17), 8261; https://doi.org/10.3390/app11178261 - 6 Sep 2021
Cited by 9 | Viewed by 2167
Abstract
The aim of the study was to identify new mathematical models and strategies that can characterize the behavior of pollutants accumulating in the soil over time, considering the special characteristics of these chemicals that cannot be degraded or destroyed easily. The paper proposes [...] Read more.
The aim of the study was to identify new mathematical models and strategies that can characterize the behavior of pollutants accumulating in the soil over time, considering the special characteristics of these chemicals that cannot be degraded or destroyed easily. The paper proposes a statistical model for assessing the accumulation of Zn in the lettuce (Lactuca sativa L.), based on three indicators that characterize the development of lettuce plants over time. The experimental data can be used to obtain interpolated variations of the mass increase functions and to determine several functions that express the time dependence of heavy metal accumulation in the plant. The resulting interpolation functions have multiple applications, being useful in generating predictions for plant growth parameters when they are grown in contaminated environments, determining whether pollutant concentrations may be hazardous for human health, and may be used to verify and validate dynamic mathematical contamination models. Full article
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18 pages, 8326 KiB  
Article
Use of Ashes from Lignite Combustion as Fillers in Rubber Mixtures to Reduce VOC Emissions
by Miroslawa Prochon, Dariusz Bieliński, Paulina Stepaniak, Magdalena Makowicz, Dominik Pietrzak and Oleksandra Dzeikala
Materials 2021, 14(17), 4986; https://doi.org/10.3390/ma14174986 - 31 Aug 2021
Viewed by 1711
Abstract
This paper presents the use of ashes from brown coal combustion (BCA) as fillers in rubber mixtures, to reduce the emission of volatile organic compounds. Two types of ash, BCA1 and BCA2, were selected as fillers for styrene–butadiene rubber (SBR). The ashes were [...] Read more.
This paper presents the use of ashes from brown coal combustion (BCA) as fillers in rubber mixtures, to reduce the emission of volatile organic compounds. Two types of ash, BCA1 and BCA2, were selected as fillers for styrene–butadiene rubber (SBR). The ashes were produced during the treatment of brown coal at the Bełchatów Power Plant in the years 2017 and 2018. The morphology and chemical composition of the ash were tested. Morphology studies using scanning microscopy showed differences in the grain sizes of the ashes, and EDS analysis showed a difference in their chemical compositions. Vulcanizates with different weight proportions of the individual ashes were produced. Mixtures were made with the addition of 10–30 pts. wt. ashes per 100 g of SBR. The addition of BCA1 ash at 10 and 30 pts. wt. reduced the emission of volatile organic compounds (VOC) while maintaining the good strength properties of the mixtures. Full article
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16 pages, 2768 KiB  
Article
Enrichment Characteristics of Cr in Chromium Slag after Pre-Reduction and Melting/Magnetic Separation Treatment
by Shaoyan Hu, Deyong Wang, Xianglong Li, Wei Zhao, Tianpeng Qu and Yun Wang
Materials 2021, 14(17), 4937; https://doi.org/10.3390/ma14174937 - 30 Aug 2021
Cited by 3 | Viewed by 2262
Abstract
Concentrating the chromium in chromium slag and improving the chromium–iron ratio is beneficial for the further utilization of chromium slag. In this paper, chromium slag obtained from a chromite lime-free roasting plant was used as the raw material. Pellets made of the chromium [...] Read more.
Concentrating the chromium in chromium slag and improving the chromium–iron ratio is beneficial for the further utilization of chromium slag. In this paper, chromium slag obtained from a chromite lime-free roasting plant was used as the raw material. Pellets made of the chromium slag and pulverized coal were reduced at different pre-reduction temperatures and then separated by a melting separation process or magnetic separation process, respectively. The mass and composition of the metallized pellets before separation, along with the alloy and tail slag after separation, were comprehensively analyzed. The experimental results showed that the output yield of alloy, iron recovery rate, and chromium content in the alloy were all higher when using melting separation than when using magnetic separation, because of the further reduction during the melting stage. More importantly, a relatively low pre-reduction temperature and selection of magnetic separation process were found to be more beneficial for chromium enrichment in slag; the highest chromium–iron ratio in tail slag can reach 2.88. Full article
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10 pages, 754 KiB  
Article
Bacterial Movement in Subsurface Soil during Winter Irrigation of Reclaimed Wastewater
by Guannan Ding, Karen Mancl, Jiyoung Lee and Olli H. Tuovinen
Sustainability 2021, 13(17), 9594; https://doi.org/10.3390/su13179594 - 26 Aug 2021
Cited by 1 | Viewed by 2143
Abstract
Processes to remove and inactivate Escherichia coli from wastewater effluents and drainage are complex and interrelated. The objective of this study was to determine if irrigation of undisinfected wastewater effluents in the winter moves bacteria to surface water through subsurface drainage, posing a [...] Read more.
Processes to remove and inactivate Escherichia coli from wastewater effluents and drainage are complex and interrelated. The objective of this study was to determine if irrigation of undisinfected wastewater effluents in the winter moves bacteria to surface water through subsurface drainage, posing a public health risk. The central Ohio study site, an open meadow constructed in the 1970s, is irrigated with lagoon effluents each summer. The irrigated area has subsurface drainage that collects for discharge in one spot. Undisinfected wastewater from a stabilization pond was irrigated for the first time in the winter of 2013/2014. E. coli was measured in the subsurface discharge during the irrigated winter season and compared to the non-irrigated previous winter season. Soil temperature and moisture were also monitored. E. coli moved to subsurface drains when the water table was above the drain. E. coli also moved to subsurface drains when the shallow soil temperature dropped to near freezing. With less winter sunlight and minimal evapotranspiration, the soil stayed moist near field capacity. Temperature appears to be the most important factor in limiting natural inactivation in subsurface soil and allowing the movement of E. coli in undisinfected wastewater effluents to the subsurface drainage systems. The results show that winter reuse of undisinfected wastewater does pose a public health risk to surface water through subsurface drainage. Therefore, disinfection of wastewater effluents used for irrigation is strongly recommended. Full article
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9 pages, 1632 KiB  
Article
Bisphenol A Effects in Aqueous Environment on Lemna minor
by Cristian-Emilian Pop, Sorin Draga, Roxana Măciucă, Roxana Niță, Nicolae Crăciun and Robert Wolff
Processes 2021, 9(9), 1512; https://doi.org/10.3390/pr9091512 - 26 Aug 2021
Cited by 30 | Viewed by 4050
Abstract
The link between different plastic waste pollutants and their impact on the natural aquatic environment and food chain remains a constant and growing issue. Bisphenol A (BPA), a known endocrine disruptor produced in large quantities primarily in the industry of polycarbonate plastics, can [...] Read more.
The link between different plastic waste pollutants and their impact on the natural aquatic environment and food chain remains a constant and growing issue. Bisphenol A (BPA), a known endocrine disruptor produced in large quantities primarily in the industry of polycarbonate plastics, can accumulate in vegetal and animal tissue, thus magnifying through trophic levels. In this study we exposed viable specimens of the aquatic plant Lemna minor under controlled conditions to 50, 100 and 200 ppm BPA levels in order to partially observe the toxic effects of BPA. Colonies ceased to form during the exposure and chlorosis was present especially in the 100 ppm group. Interestingly enough, a high density formation of non-fermenting bacteria as well as coliforms was also observed in the BPA exposed cultures but not in the control groups. The levels of Malondialdehyde (MDA) in the vegetal tissue indicated cellular insults and severe damage, results that were correlated with the HPLC BPA determined concentrations of 0.1%, 0.2% and 0.4%. Full article
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20 pages, 2544 KiB  
Review
Analysis of the Status and Improvement of Microalgal Phosphorus Removal from Municipal Wastewater
by Yilin Mao, Rongwei Xiong, Xiufang Gao, Li Jiang, Yancong Peng and Yan Xue
Processes 2021, 9(9), 1486; https://doi.org/10.3390/pr9091486 - 24 Aug 2021
Cited by 20 | Viewed by 3778
Abstract
Phosphorus, as one of the main pollutants in municipal sewage, has received increasing attention recently. Phosphorus recovery also increases the sustainable development of municipal wastewater. Since algae have the ability to effectively redirect nutrients, including phosphorus, from municipal sewage to algae biomass, municipal [...] Read more.
Phosphorus, as one of the main pollutants in municipal sewage, has received increasing attention recently. Phosphorus recovery also increases the sustainable development of municipal wastewater. Since algae have the ability to effectively redirect nutrients, including phosphorus, from municipal sewage to algae biomass, municipal sewage treatments involving microalgae have piqued the interest of many researchers. The phosphorus removal depends on the potential of the microalgae to absorb, preserve, or degrade phosphorus in municipal wastewater. It is, therefore, of great interest to study the mechanisms underlying the absorption, storage, and degradation of phosphorus by microalgae to ensure the viability of this phosphorus removal process in wastewater. The objectives of this review were to summarize phosphorus metabolism in microalgae, examine key external and internal factors impacting phosphorous removal by microalgae from wastewater, and examine the status of phosphorous-metabolism-related research to improve our understanding of microalgae-based municipal wastewater treatments. In addition, the methods of recovery of microalgae after phosphorous removal were summarized to ensure the sustainability of municipal wastewater treatment. Finally, a potential approach using nanomaterials was proposed to enhance the overall phosphorous removal performance in municipal wastewater through the addition of nanoparticles such as magnesium and iron. Full article
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12 pages, 6561 KiB  
Article
Influence of Hydrothermal Pretreatment Temperature on the Hydration Properties and Direct Carbonation Efficiency of Al-Rich Ladle Furnace Refining Slag
by Yi Huang and Guo Xiong
Processes 2021, 9(8), 1458; https://doi.org/10.3390/pr9081458 - 21 Aug 2021
Viewed by 1724
Abstract
The influence of hydrothermal pretreatment temperature on the hydration products and carbonation efficiency of Al-rich LF slag was investigated. The results showed that the carbonation efficiency was strongly dependent on the morphology of hydration products and the hydration extent of the raw slag. [...] Read more.
The influence of hydrothermal pretreatment temperature on the hydration products and carbonation efficiency of Al-rich LF slag was investigated. The results showed that the carbonation efficiency was strongly dependent on the morphology of hydration products and the hydration extent of the raw slag. Hydrothermal pretreatment at 20 °C or 80 °C favored the formation of flake-shaped products with a higher specific surface area and therefore resulted in a higher CO2 uptake of 20 °C and 80 °C-pretreated slags (13.66 wt% and 10.82 wt%, respectively). However, hydrothermal pretreatment at 40 °C, 60 °C or 100 °C led to the rhombohedral-shaped calcite layer surrounding the unreacted core of the raw slag and the formation of fewer flake-shaped products, resulting in a lower CO2 uptake of 40 °C, 60 °C and 100 °C-pretreated slags (9.21 wt%, 9.83 wt%, and 6.84 wt%, respectively). Full article
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17 pages, 1582 KiB  
Article
A Unique Unified Wind Speed Approach to Decision-Making for Dispersed Locations
by Ayman M. Mansour, Abdulaziz Almutairi, Saeed Alyami, Mohammad A. Obeidat, Dhafer Almkahles and Jagabar Sathik
Sustainability 2021, 13(16), 9340; https://doi.org/10.3390/su13169340 - 20 Aug 2021
Cited by 9 | Viewed by 2307
Abstract
The repercussions of high levels of environmental pollution coupled with the low reserves and increased costs of traditional energy sources have led to the widespread adaptation of wind energy worldwide. However, the expanded use of wind energy is accompanied by major challenges for [...] Read more.
The repercussions of high levels of environmental pollution coupled with the low reserves and increased costs of traditional energy sources have led to the widespread adaptation of wind energy worldwide. However, the expanded use of wind energy is accompanied by major challenges for electric grid operators due to the difficulty of controlling and forecasting the production of wind energy. The development of methods for addressing these problems has therefore attracted the interest of numerous researchers. This paper presents an innovative method for assessing wind speed in different and widely spaced locations. The new method uses wind speed data from multiple sites as a single package that preserves the characteristics of the correlations among those sites. Powerful Waikato Environment for Knowledge Analysis (Weka) machine learning software has been employed for supporting data preprocessing, clustering, classification, visualization, and feature selection and for using a standard algorithm to construct decision trees according to a training set. The resultant arrangement of the sites according to likely wind energy productivity facilitates enhanced decisions related to the potential for the effective operation of wind energy farms at the sites. The proposed method is anticipated to provide network operators with an understanding of the possible productivity of each site, thus facilitating their optimal management of network operations. The results are also expected to benefit investors interested in establishing profitable projects at those locations. Full article
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10 pages, 2204 KiB  
Article
Application of an Electrical Low Pressure Impactor (ELPI) for Residual Particle Measurement in an Epitaxial Growth Reactor
by Seungjae Lee, Dongbin Kim, Yujin Cho, Eunmi Kim, Pengzhan Liu, Dong-Bin Kwak, Seungho Keum, Hongkang Lim and Taesung Kim
Appl. Sci. 2021, 11(16), 7680; https://doi.org/10.3390/app11167680 - 20 Aug 2021
Viewed by 3395
Abstract
The purpose of this study was to determine the feasibility of using an electrical low pressure impactor (ELPI) for analyzing residual particles in a Si epitaxial growth process chamber and establish an application technique. Prior to experimental measurements, some preliminary works were conducted, [...] Read more.
The purpose of this study was to determine the feasibility of using an electrical low pressure impactor (ELPI) for analyzing residual particles in a Si epitaxial growth process chamber and establish an application technique. Prior to experimental measurements, some preliminary works were conducted, including an inlet improvement of a cascade impactor, vacuum fitting fastening and flow rate adjustment, and a vacuum leak test. After that, residual particles in the process chamber were measured during N2 gas purge using an ELPI due to its advantages including the real-time measurement of particles and the ability to separate and collect particles by their diameters. In addition, ELPI could be used to obtain particle size distribution and see the distribution trend for both number and mass concentration. The results of the real-time analysis of the total particle count revealed that the concentration at the endpoint compared to that at the beginning of the measurement by decreased 36.9%. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM–EDS) analysis of collected particles was performed using two types of substrates: Al foil and a Si wafer. The results showed that most particles were Si particles, while few particles had Si and Cl components. ELPI has the clear advantages of real-time particle concentration measurement and simultaneous collection. Thus, we believe that it can be more actively used for particle measurement and analysis in the semiconductor industry, which has many critical micro/nanoparticle issues. Full article
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14 pages, 2240 KiB  
Article
Antibiotic Resistance Gene Transformation and Ultrastructural Alterations of Lettuce (Lactuca sativa L.) Resulting from Sulfadiazine Accumulation in Culture Solution
by Liang Mei, Ying-Xin Chen, Chao Wang, Jia-Hua Chen, Zhi-Jin Zhang, Min-Yao Zhou, Jin-Tao Feng and Yan Wang
Processes 2021, 9(8), 1451; https://doi.org/10.3390/pr9081451 - 20 Aug 2021
Viewed by 2186
Abstract
The research herein explored the possible mechanism of toxicity of the antibiotic sulfadiazine (SD) and the related antibiotic resistance gene transformation in lettuce by systematically investigating its growth responses, ultrastructural changes, and antibiotic resistance gene transformation via solution culture experiments. The results showed [...] Read more.
The research herein explored the possible mechanism of toxicity of the antibiotic sulfadiazine (SD) and the related antibiotic resistance gene transformation in lettuce by systematically investigating its growth responses, ultrastructural changes, and antibiotic resistance gene transformation via solution culture experiments. The results showed that SD mainly accumulated in the roots of lettuce at concentrations ranging from 6.48 to 120.87 μg/kg, which were significantly higher than those in leaves (3.90 to 16.74 μg/kg). Lower concentrations of SD (0.5 and 2.0 mg/L) in the culture nutrient solution exerted little effect on lettuce growth, while at SD concentrations higher than 10 mg/L, the growth of lettuce was significantly inhibited, manifesting as shorter root length and lower dry matter yield of whole lettuce plants. Compared with that for the control group, the absolute abundance of bacteria in the root endophyte, rhizosphere, and phyllosphere communities under different concentrations of SD treatment decreased significantly. sul1 and sul2 mainly accumulated in the root endophyte community, at levels significantly higher than those in the leaf endophyte community. Studies of electrolyte leakage and ultrastructural characteristics of root and leaf cells indicated that lettuce grown in culture solutions with high SD concentrations suffered severe damage and disintegration of the cell walls of organs, especially chloroplasts, in leaves. Furthermore, the possible mechanism of SD toxicity in lettuce was confirmed to start with the roots, followed by a free flow of SD into the leaves to destroy the chloroplasts in the leaf cells, which ultimately reduced photosynthesis and decreased plant growth. Studies have shown that antibiotic residues have negative effects on the growth of lettuce and highlight a potential risk of the development and spread of antibiotic resistance in vegetable endophyte systems. Full article
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19 pages, 855 KiB  
Review
Anti-Smog Building and Civil Engineering Structures
by Elżbieta Stanaszek-Tomal
Processes 2021, 9(8), 1446; https://doi.org/10.3390/pr9081446 - 19 Aug 2021
Cited by 9 | Viewed by 7556
Abstract
Currently, people worldwide, in the period from September to April, observe with their own eyes and feel the pollution of the air, called smog, in their own breath. The biggest cause of smog and the source of air pollution is burning rubbish in [...] Read more.
Currently, people worldwide, in the period from September to April, observe with their own eyes and feel the pollution of the air, called smog, in their own breath. The biggest cause of smog and the source of air pollution is burning rubbish in stoves. Other causes include exhaust fumes from large factories, burning coal in furnaces, and car exhaust fumes. Smog is an unnatural phenomenon, directly related to human activity. The weather is becoming worse. On no-wind, foggy days, the smog phenomenon is the most troublesome for city dwellers. Smog persists in European countries from November to April, during the heating season. The harmful effect of smog affects almost the entire human body. Every year, air pollution causes the death of approximately 26,000–48,000 people. At the same time, poor air quality reduces life expectancy by up to a year. The purpose of this article is to present buildings and finishing elements that can help in the fight against air pollution. Full article
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26 pages, 3183 KiB  
Review
Remediation of Petroleum-Contaminated Soils with Microbial and Microbial Combined Methods: Advances, Mechanisms, and Challenges
by Xin Sui, Xuemei Wang, Yuhuan Li and Hongbing Ji
Sustainability 2021, 13(16), 9267; https://doi.org/10.3390/su13169267 - 18 Aug 2021
Cited by 86 | Viewed by 14403
Abstract
The petroleum industry’s development has been supported by the demand for petroleum and its by-products. During extraction and transportation, however, oil will leak into the soil, destroying the structure and quality of the soil and even harming the health of plants and humans. [...] Read more.
The petroleum industry’s development has been supported by the demand for petroleum and its by-products. During extraction and transportation, however, oil will leak into the soil, destroying the structure and quality of the soil and even harming the health of plants and humans. Scientists are researching and developing remediation techniques to repair and re-control the afflicted environment due to the health risks and social implications of petroleum hydrocarbon contamination. Remediation of soil contamination produced by petroleum hydrocarbons, on the other hand, is a difficult and time-consuming job. Microbial remediation is a focus for soil remediation because of its convenience of use, lack of secondary contamination, and low cost. This review lists the types and capacities of microorganisms that have been investigated to degrade petroleum hydrocarbons. However, investigations have revealed that a single microbial remediation faces difficulties, such as inconsistent remediation effects and substantial environmental consequences. It is necessary to understand the composition and source of pollutants, the metabolic genes and pathways of microbial degradation of petroleum pollutants, and the internal and external aspects that influence remediation in order to select the optimal remediation treatment strategy. This review compares the degradation abilities of microbial–physical, chemical, and other combination remediation methods, and highlights the degradation capabilities and processes of the greatest microbe-biochar, microbe–nutrition, and microbe–plant technologies. This helps in evaluating and forecasting the chemical behavior of contaminants with both short- and long-term consequences. Although there are integrated remediation strategies for the removal of petroleum hydrocarbons, practical remediation remains difficult. The sources and quantities of petroleum pollutants, as well as their impacts on soil, plants, and humans, are discussed in this article. Following that, the focus shifted to the microbiological technique of degrading petroleum pollutants and the mechanism of the combined microbial method. Finally, the limitations of existing integrated microbiological techniques are highlighted. Full article
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12 pages, 2791 KiB  
Article
An Innovative Digestion Method: Ultrasound-Assisted Electrochemical Oxidation for the Onsite Extraction of Heavy Metal Elements in Dairy Farm Slurry
by Chenyu Li, Bin Xue, Shang Wang, Xi Zhang, Chen Zhao, Xiaobo Yang, Run Zhao, Lin Dai, Shengqi Su, Haoqi Xu, Zhiqiang Shen, Zhigang Qiu and Jingfeng Wang
Materials 2021, 14(16), 4562; https://doi.org/10.3390/ma14164562 - 13 Aug 2021
Cited by 1 | Viewed by 1653
Abstract
Dairy farm slurry is an important biomass resource that can be used as a fertilizer and in energy utilization and chemical production. This study aimed to establish an innovative ultrasound-assisted electrochemical oxidation (UAEO) digestion method for the rapid and onsite analysis of the [...] Read more.
Dairy farm slurry is an important biomass resource that can be used as a fertilizer and in energy utilization and chemical production. This study aimed to establish an innovative ultrasound-assisted electrochemical oxidation (UAEO) digestion method for the rapid and onsite analysis of the heavy metal (HM) contamination level of dairy slurry. The effects of UAEO operating parameters on digestion efficiency were tested based on Cu and Zn concentrations in a dairy slurry sample. The results showed that Cu and Zn digestion efficiency was (96.8 ± 2.6) and (98.5 ± 2.9)%, respectively, with the optimal UAEO operating parameters (digestion time: 45 min; ultrasonic power: 400 W; NaCl concentration: 10 g/L). The digestion recovery rate experiments were then operated with spiked samples to verify the digestion effect on broad-spectrum HMs. When the digestion time reached 45 min, all digestion recovery rates exceeded 90%. Meanwhile, free chlorine concentration, particle size distribution, and micromorphology were investigated to demonstrate the digestion mechanism. It was found that 414 mg/L free chorine had theoretically enough oxidative ability, and the ultrasound intervention could deal with the blocky undissolved particles attributed to its crushing capacity. The results of particle size distribution showed that the total volume and bulky particle proportion had an obvious decline. The micromorphology demonstrated that the ultrasound intervention fragmented the bulky particles, and electrochemical oxidation made irregular blocky structures form arc edge and cellular structures. The aforementioned results indicated that UAEO was a novel and efficient method. It was fast and convenient. Additionally, it ensured digestion efficiency and thus had a good application prospect. Full article
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10 pages, 2434 KiB  
Article
Removal Performance and Mechanism of Benzo(b)Fluorathene Using MnO2 Nanoflower/Graphene Oxide Composites
by Qingqing Cao, Siqi Lu, Wenjun Yin, Yan Kang, Naihao Yang, Yudong Hou and Zizhang Guo
Materials 2021, 14(16), 4402; https://doi.org/10.3390/ma14164402 - 6 Aug 2021
Cited by 1 | Viewed by 1822
Abstract
High-ring polycyclic aromatic hydrocarbons (PAHs, Benzo[b]fluorathene (BbFA), etc.) are difficult to biodegrade in the water environment. To address this issue, an innovative method for the preparation of MnO2 nanoflower/graphene oxide composite (MnO2 NF/GO) was proposed for adsorption removal of BbFA. The [...] Read more.
High-ring polycyclic aromatic hydrocarbons (PAHs, Benzo[b]fluorathene (BbFA), etc.) are difficult to biodegrade in the water environment. To address this issue, an innovative method for the preparation of MnO2 nanoflower/graphene oxide composite (MnO2 NF/GO) was proposed for adsorption removal of BbFA. The physicochemical properties of MnO2 NF/GO were characterized by SEM, TEM, XRD, and N2 adsorption/desorption and XPS techniques. Results show that the MnO2 NF/GO had well-developed specific surface area and functional groups. Batch adsorption experiment results showed that adsorption capacity for BbFA was 74.07 mg/g. The pseudo-second-order kinetic model and Freundlich isotherm model are fitted well to the adsorption data. These show electron-donor-acceptor interaction; especially π-π interaction and π complexation played vital roles in BbFA removal onto MnO2 NF/GO. The study highlights the promising potential adsorbent for removal of PAHs. Full article
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32 pages, 7786 KiB  
Review
Improving Gas-Sensing Performance Based on MOS Nanomaterials: A Review
by Shirui Xue, Sicheng Cao, Zhaoling Huang, Daoguo Yang and Guoqi Zhang
Materials 2021, 14(15), 4263; https://doi.org/10.3390/ma14154263 - 30 Jul 2021
Cited by 48 | Viewed by 5678
Abstract
In order to solve issues of air pollution, to monitor human health, and to promote agricultural production, gas sensors have been used widely. Metal oxide semiconductor (MOS) gas sensors have become an important area of research in the field of gas sensing due [...] Read more.
In order to solve issues of air pollution, to monitor human health, and to promote agricultural production, gas sensors have been used widely. Metal oxide semiconductor (MOS) gas sensors have become an important area of research in the field of gas sensing due to their high sensitivity, quick response time, and short recovery time for NO2, CO2, acetone, etc. In our article, we mainly focus on the gas-sensing properties of MOS gas sensors and summarize the methods that are based on the interface effect of MOS materials and micro–nanostructures to improve their performance. These methods include noble metal modification, doping, and core-shell (C-S) nanostructure. Moreover, we also describe the mechanism of these methods to analyze the advantages and disadvantages of energy barrier modulation and electron transfer for gas adsorption. Finally, we put forward a variety of research ideas based on the above methods to improve the gas-sensing properties. Some perspectives for the development of MOS gas sensors are also discussed. Full article
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14 pages, 2159 KiB  
Article
Nano-Porous-Silicon Powder as an Environmental Friend
by Marwa Nabil, Kamal Reyad Mahmoud, Raghda Nomier, El-Maghraby El-Maghraby and Hussien Motaweh
Materials 2021, 14(15), 4252; https://doi.org/10.3390/ma14154252 - 30 Jul 2021
Cited by 1 | Viewed by 2263
Abstract
Nano-porous silicon (NPS) powder synthesis is performed by means of a combination of the ultra-sonication technique and the alkali chemical etching process, starting with a commercial silicon powder. Various characterization techniques {X-ray powder diffraction, transmission electron microscopy, Fourier Transform Infrared spectrum, and positron [...] Read more.
Nano-porous silicon (NPS) powder synthesis is performed by means of a combination of the ultra-sonication technique and the alkali chemical etching process, starting with a commercial silicon powder. Various characterization techniques {X-ray powder diffraction, transmission electron microscopy, Fourier Transform Infrared spectrum, and positron annihilation lifetime spectroscopy} are used for the description of the product’s properties. The NPS product is a new environmentally friendly material used as an adsorbent agent for the acidic azo-dye, Congo red dye. The structural and free volume changes in NPS powder are probed using positron annihilation lifetime (PALS) and positron annihilation Doppler broadening (PADB) techniques. In addition, the mean free volume (VF), as well as fractional free volume (Fv), are also studied via the PALS results. Additionally, the PADB provides a clear relationship between the core and valence electrons changes, and, in addition, the number of defect types present in the synthesized samples. The most effective parameter that affects the dye removal process is the contact time value; the best time for dye removal is 5 min. Additionally, the best value of the CR adsorption capacity by NPS powder is 2665.3 mg/g at 100 mg/L as the initial CR concentration, with an adsorption time of 30 min, without no impact from temperature and pH. So, 5 min is the enough time for the elimination of 82.12% of the 30 mg/L initial concentration of CR. This study expresses the new discovery of a cheap and safe material, in addition to being environmentally friendly, without resorting to any chemical additives or heat treatments. Full article
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21 pages, 12161 KiB  
Article
Monitoring Study on Dust Dispersion Properties during Earthwork Construction
by Qiming Luo, Lepeng Huang, Yuhong Liu, Xuanyi Xue, Fengbin Zhou and Jianmin Hua
Sustainability 2021, 13(15), 8451; https://doi.org/10.3390/su13158451 - 28 Jul 2021
Cited by 10 | Viewed by 2603
Abstract
Dust generated in earthwork construction activities can seriously affect the air quality at a construction site and have adverse effects on the health of construction workers. To accurately and quantitively analyze the distribution characteristics of construction dust and the effect of dust prevention [...] Read more.
Dust generated in earthwork construction activities can seriously affect the air quality at a construction site and have adverse effects on the health of construction workers. To accurately and quantitively analyze the distribution characteristics of construction dust and the effect of dust prevention measures during earthwork construction under normal construction and construction with dust control measures, multiple collection points and one meteorological parameter collection point were placed at the construction site. From half an hour before the construction to half an hour after the construction, the particle concentration was recorded once every minute. The monitoring results indicated that there was a significant positive correlation between dust concentration during earthwork construction and the number of soil shipments. The dust concentration was highest at the earth excavation site, followed by the area of the waste truck’s transportation path. Earth excavation primarily resulted in the generation of many coarse particles, the concentration of which was the highest near the excavation site. The average concentration increments of PM2.5 and TSP (total suspended particulate) caused by earthwork construction were 55.06 and 375.17 μg/m3 at the construction site, respectively. The concentration increment of PM2.5 and TSP decreased by 72.01% and 40.16%, respectively, when a spray system and artificial sprinkling were adopted. Through the methodology and results of this study, construction companies can systemically plan their construction work by considering the key equipment to be used and can effectively manage the pollutants found within construction sites. Full article
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