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Keywords = tetracycline purification

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20 pages, 1759 KiB  
Article
Chromium Ferrite Supported on Activated Carbon from Olive Mill Solid Waste for the Photo-Fenton Degradation of Pollutants from Wastewater Using LED Irradiation
by Malak Hamieh, Sireen Al Khawand, Nabil Tabaja, Khaled Chawraba, Mohammad Hammoud, Sami Tlais, Tayssir Hamieh and Joumana Toufaily
AppliedChem 2025, 5(3), 15; https://doi.org/10.3390/appliedchem5030015 - 11 Jul 2025
Viewed by 369
Abstract
In this study, chromium ferrite (FeCr; CrFe2O4) nanoparticles supported on activated carbon (AC), obtained from agricultural olive mill solid waste, were synthesized via a simple hydrothermal process. The structural, morphological, optical, and chemical properties of the FeCr/AC composite were [...] Read more.
In this study, chromium ferrite (FeCr; CrFe2O4) nanoparticles supported on activated carbon (AC), obtained from agricultural olive mill solid waste, were synthesized via a simple hydrothermal process. The structural, morphological, optical, and chemical properties of the FeCr/AC composite were characterized using XRD, SEM, EDX, DRS, BET, and FTIR techniques. The FeCr/AC composite was applied as a heterogeneous photo-Fenton catalyst for the degradation of methylene blue (MB) dye in an aqueous solution under 25 W visible-light LED irradiation. Critical operational factors, such as FeCr/AC dosage, pH, MB concentration, and H2O2 levels, were optimized. Under optimal conditions, 97.56% of MB was removed within 120 min of visible-light exposure, following pseudo-first-order kinetics. The composite also exhibited high efficiency in degrading methyl orange dye (95%) and tetracycline antibiotic (88%) within 180 min, with corresponding first-order rate constants of 0.0225 min−1 and 0.0115 min−1, respectively. This study highlights the potential of FeCr/AC for treating water contaminated with dyes and pharmaceuticals, in line with the Sustainable Development Goals (SDGs) for water purification. Full article
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15 pages, 3020 KiB  
Article
Metal Oxide-Modified PES Membranes for Efficient Separation of Oil-in-Water Emulsions and Trace Organic Compounds
by Jinze Li, Wensheng Yang, Yang Xu, Chengfeng Sun, Yingying Zhu and Geng Chen
Catalysts 2025, 15(6), 604; https://doi.org/10.3390/catal15060604 - 19 Jun 2025
Viewed by 579
Abstract
The efficient removal of emulsified oil and trace organic pollutants via forward osmosis (FO) technology remains challenging due to limited water flux and membrane fouling. In this study, a series of metal oxide-modified PES-based composite FO membranes were fabricated and systematically evaluated to [...] Read more.
The efficient removal of emulsified oil and trace organic pollutants via forward osmosis (FO) technology remains challenging due to limited water flux and membrane fouling. In this study, a series of metal oxide-modified PES-based composite FO membranes were fabricated and systematically evaluated to compare the effects of ZnO, Al2O3, and CuO nanoparticles on membrane structure and separation performance. The results demonstrated that the membrane modified with 0.04 g of ZnO nanoparticles achieved optimal synergy in terms of hydrophilicity, surface charge, and pore structure. The pure water flux increased from 5.48 L·m−2·h−1 for the pristine membrane to 18.5 L·m−2·h−1 for the ZnO-modified membrane, exhibiting a 237.5% increase in pure water flux compared to the pristine PES membrane, an oil rejection rate exceeding 97%, and over 95% rejection of typical negatively charged trace organic pollutants such as ibuprofen and tetracycline. Moreover, the ZnO-modified membrane showed excellent antifouling performance and structural stability in various organic solvent systems. This study not only optimized the interfacial chemistry and microstructure of the FO membrane but also enhanced pollutant repellence and the self-cleaning capability through increased hydrophilicity and surface negative charge density. These findings highlight the significant potential of ZnO modification for enhancing the overall performance of FO membranes and provide an effective strategy for developing high-performance, broadly applicable FO membranes for complex water purification. Full article
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15 pages, 4715 KiB  
Article
In Situ Anchored, Ultrasmall, Oxygen Vacancy-Rich TiO2−x on Carbonized Bacterial Cellulose for the Efficient Adsorption and Separation of Organic Pollutants
by Man Zhou, Yanli Zhou, Minmin Ni, Yuzhe Zhang, Song Xu, Hao Ma, Jian Zhou, Jin Zhao, Liwei Lin and Zhongyu Li
Nanomaterials 2025, 15(7), 514; https://doi.org/10.3390/nano15070514 - 28 Mar 2025
Viewed by 457
Abstract
Superior selective adsorption of organic dye is still a big challenge in the process of dye wastewater treatment. Meanwhile, low-price and environmentally friendly biomass-based adsorbents show huge potential in the fields of separation and purification. In this study, we adopted the “hydrolysis–calcination method” [...] Read more.
Superior selective adsorption of organic dye is still a big challenge in the process of dye wastewater treatment. Meanwhile, low-price and environmentally friendly biomass-based adsorbents show huge potential in the fields of separation and purification. In this study, we adopted the “hydrolysis–calcination method” to develop a novel in situ anchoring strategy for ultrasmall TiO2−x on carbonized bacterial cellulose (CBC), which was derived from natural bacterial cellulose. Notably, 3D networks of porous CBC played a dual role for both providing hydrolytic sites and controlling the oxygen vacancies (Vo) of TiO2−x. As for the single-dye adsorption, the TiO2−x/CBC had a strong adsorption ability (101.4 mg/g) for removing methylene blue (MB), which was much higher than that of methyl orange (MO), malachite green (MG), rhodamine B (RhB), and tetracyclines (TC). Moreover, under the optimized carbonization temperature (Tc) of 300 °C, the TiO2−x/CBC-300 exhibited an outstanding separation efficiency of 97.07% for the MB/MO solution. Detailed analysis confirmed that Tc was a key regulator for adjusting the Vo concentration, which directly influenced the surface charge density and, further, the separation efficiency of TiO2−x/CBC. Additionally, the used adsorbent could be easily regenerated from washing by ethanol. After 4 regenerations, the adsorption efficiency declined only by 6.9% after 20 min and 13.6% after 120 min adsorption, respectively. Ultimately, this oxygen vacancy-rich TiO2−x/BC system illuminated good prospects for mixed dye wastewater adsorption and separation. Full article
(This article belongs to the Special Issue Nano-Enabled Materials for Clean Water and Energy Generation)
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18 pages, 5225 KiB  
Article
Laser Synthesis and Photocatalytic Properties of Bismuth Oxyhalides Nanoparticles
by Vyacheslav E. Korepanov, Olesia A. Reutova, Tamara S. Kharlamova, Olga V. Vodyankina, Sergei A. Kulinich and Valery A. Svetlichnyi
Nanomaterials 2024, 14(24), 1995; https://doi.org/10.3390/nano14241995 - 12 Dec 2024
Viewed by 1649
Abstract
Photocatalysis offers a powerful approach for water purification from toxic organics, hydrogen production, biosolids processing, and the conversion of CO2 into useful products. Further advancements in photocatalytic technologies depend on the development of novel, highly efficient catalysts and optimized synthesis methods. This [...] Read more.
Photocatalysis offers a powerful approach for water purification from toxic organics, hydrogen production, biosolids processing, and the conversion of CO2 into useful products. Further advancements in photocatalytic technologies depend on the development of novel, highly efficient catalysts and optimized synthesis methods. This study aimed to develop a laser synthesis technique for bismuth oxyhalide nanoparticles (NPs) as efficient and multifunctional photocatalysts. Laser ablation of a Bi target in a solution containing halogen salt precursors, followed by laser plasma treatment of the resulting colloid, yielded crystalline bismuth oxyhalides (BixOyXz, where X = Cl, Br, or I) NPs without the need for additional annealing. The composition, structure, morphology, and optical properties of the synthesized BixOyXz (X = Cl, Br, I) NPs were characterized using XRD analysis, electron microscopy, Raman spectroscopy, and UV-Vis spectroscopy. The effect of the halogen on the photocatalytic activity of the double oxides was investigated. The materials exhibited high photocatalytic activity in the degradation of persistent model pollutants like Rhodamine B, tetracycline, and phenol. Furthermore, the BixOyXz NPs demonstrated good efficiency and high yield in the selective oxidation of 5-hydroxymethylfurfural (5-HMF) to 2,5-furandicarboxylic acid (FDCA). The obtained results highlight the promising potential of this laser synthesis approach for producing high-performance bismuth oxyhalide photocatalysts. Full article
(This article belongs to the Special Issue Nanomaterials for Green and Sustainable World)
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15 pages, 4134 KiB  
Article
BioTemplated Fe3+-Doped g-C3N4 Heterojunction Micromotors for the Degradation of Tetracycline through the Photo-Fenton Reaction
by Qingbao Gan, Jianwei Zhang, Jinglin Wang, Yuntian Wei, Shikun Chen, Shuguang Cai, Xueqing Xiao and Chan Zheng
Catalysts 2024, 14(9), 579; https://doi.org/10.3390/catal14090579 - 30 Aug 2024
Cited by 2 | Viewed by 1210
Abstract
The excessive discharge of antibiotics into aquatic systems is a major issue in many countries worldwide and poses a threat to human health and the sustainable development of society. Hence, developing efficient treatment methods and purification technologies to degrade antibiotics is essential. Herein, [...] Read more.
The excessive discharge of antibiotics into aquatic systems is a major issue in many countries worldwide and poses a threat to human health and the sustainable development of society. Hence, developing efficient treatment methods and purification technologies to degrade antibiotics is essential. Herein, we present the synthesis of low-cost, self-propelled tubular Fe3+-incorporated graphitic carbon nitride (g-C3N4-Fe@KF) micromotors using kapok fibers (KFs) as templates and their application as photo-catalysts for the photo-Fenton degradation of tetracycline (TC) under visible-light irradiation. The g-C3N4-Fe@KF micromotors moved rapidly when being propelled by oxygen bubbles generated in a hydrogen peroxide (H2O2) solution as a result of a photo-assisted Fenton reaction. The motion behavior of the g-C3N4-Fe@KF micromotors was dependent on the concentration of H2O2 and the length of the micromotors. The propulsion mechanism was discussed in detail. The micromotors efficiently degraded antibiotics via the photo-Fenton process. Photo-Fenton degradation efficiency was attributed to the synergistic effects of the doped Fe3+ and g-C3N4 under visible-light irradiation and self-propulsion of the micromotors. In addition, the micromotors possessed good reusability, thereby efficiently realizing multiple cycles of degradation. The current work offers an avenue for the design of micromotors, using inexpensive approaches, for various potential environmental applications. Full article
(This article belongs to the Section Catalytic Materials)
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15 pages, 3890 KiB  
Article
Rational Engineering of Nanostructured NiS/GO/PVA for Efficient Photocatalytic Degradation of Organic Pollutants
by Arafat Toghan, Naglaa Roushdy, Hanan Alhussain and Noha A. Elessawy
Catalysts 2024, 14(9), 567; https://doi.org/10.3390/catal14090567 - 28 Aug 2024
Cited by 2 | Viewed by 1304
Abstract
A novel nanocomposite film synthesized from an inexpensive and easily accessible polymer such as poly (vinyl alcohol) (PVA), which is coated with nickel sulfide (NiS) and graphene oxide (GO), was obtained from used drinking-water bottles. The produced coated film was examined as a [...] Read more.
A novel nanocomposite film synthesized from an inexpensive and easily accessible polymer such as poly (vinyl alcohol) (PVA), which is coated with nickel sulfide (NiS) and graphene oxide (GO), was obtained from used drinking-water bottles. The produced coated film was examined as a potential photocatalyst film for wastewater treatment promotion in a batch system for the removal of methylene blue (MB) and tetracycline (TC) antibiotics. The experimental results show that the presence of GO significantly increases the photocatalytic efficiency of NiS, and the MB and TC degradation results proved that the incorporation of GO with NiS led to a more than one-and-a-half-fold increase in the removal percentage in comparison with the NiS/PVA-coated film. After 30 min of illumination using GO/NiS/PVA-coated film, the removal efficiency reached 86% for MB and 64% for TC. The photodegradation kinetic rate followed the pseudo-first-order rate. Furthermore, the response surface methodology (RSM) model was utilized to study and optimize several operating parameters. The ideal circumstances to achieve 91% elimination of MB are 12 mg L−1 MB initial concentration, two lamps, and an illumination time of 15 min; however, to achieve 85% TC removal, 11 mg L−1 TC initial concentration, two lamps, and a 45 min illumination time should be used. The fabricated nanocomposite photocatalyst film seems to have promise for use in water purification systems. Full article
(This article belongs to the Special Issue Advancements in Photocatalysis for Environmental Applications)
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20 pages, 8536 KiB  
Article
Innovative Bi5O7I/MIL-101(Cr) Compounds: A Leap Forward in Photocatalytic Tetracycline Removal
by Jie Hong, Zhaohan Chu, Claudia Li, Wanliang Yang, Sibudjing Kawi and Qinong Ye
Int. J. Mol. Sci. 2024, 25(12), 6759; https://doi.org/10.3390/ijms25126759 - 19 Jun 2024
Cited by 4 | Viewed by 1477
Abstract
In environmental chemistry, photocatalysts for eliminating organic contaminants in water have gained significant interest. Our study introduces a unique heterostructure combining MIL-101(Cr) and bismuth oxyiodide (Bi5O7I). We evaluated this nanostructure’s efficiency in adsorbing and degrading tetracycline (TC) under visible [...] Read more.
In environmental chemistry, photocatalysts for eliminating organic contaminants in water have gained significant interest. Our study introduces a unique heterostructure combining MIL-101(Cr) and bismuth oxyiodide (Bi5O7I). We evaluated this nanostructure’s efficiency in adsorbing and degrading tetracycline (TC) under visible light. The Bi5O7I@MIL-101(Cr) composite, with a surface area of 637 m2/g, prevents self-aggregation seen in its components, enhancing visible light absorption. Its photocatalytic efficiency surpassed Bi5O7I and MIL-101(Cr) by 33.4 and 9.2 times, respectively. Comprehensive analyses, including scanning electron microscopy (SEM) and transmission electron microscopy (TEM), confirmed the successful formation of the heterostructure with defined morphological characteristics. BET analysis demonstrated its high surface area, while X-ray diffraction (XRD) confirmed its crystallinity. Electron spin resonance (ESR) tests showed significant generation of reactive oxygen species (ROS) like h+ and·•O2 under light, crucial for TC degradation. The material maintained exceptional durability over five cycles. Density functional theory (DFT) simulations and empirical investigations revealed a type I heterojunction between Bi5O7I and MIL-101(Cr), facilitating efficient electron–hole pair separation. This study underscores the superior photocatalytic activity and stability of Bi5O7I@MIL-101(Cr), offering insights into designing innovative photocatalysts for water purification. Full article
(This article belongs to the Section Materials Science)
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18 pages, 18299 KiB  
Article
Preparation of 2D/2D CoAl-LDH/BiO(OH)XI1−X Heterojunction Catalyst with Enhanced Visible–Light Photocatalytic Activity for Organic Pollutants Degradation in Water
by Liying Che and Huanhuan Ji
Water 2024, 16(11), 1467; https://doi.org/10.3390/w16111467 - 21 May 2024
Cited by 2 | Viewed by 1478
Abstract
Hydrotalcite/bismuth solid solution (2D/2D CoAl-LDH/BiO(OH)XI1−X) heterojunction photocatalysts were fabricated through a hydrothermal route. Because of their identical layered structure and interlayer hydroxides, CoAl-LDH(2D) and BiO(OH)XI1−X(2D) form a tightly bonded heterojunction, resulting in efficient light absorption, [...] Read more.
Hydrotalcite/bismuth solid solution (2D/2D CoAl-LDH/BiO(OH)XI1−X) heterojunction photocatalysts were fabricated through a hydrothermal route. Because of their identical layered structure and interlayer hydroxides, CoAl-LDH(2D) and BiO(OH)XI1−X(2D) form a tightly bonded heterojunction, resulting in efficient light absorption, excitation, and carrier migration conversion. At the same time, the large specific surface area and abundant hydroxyl groups of the layered structure make the heterojunction catalyst exhibit excellent performance in the photocatalytic degradation of organic pollutants. Under visible light irradiation and in the presence of 1 g/L of the catalyst, 10 mg/L of methyl orange (MO) in water could be completely degraded within 20 min, and the degradation rate of tetracycline (TC) reached 99.23% within 5 min. CoAl-LDH/BiO(OH)XI1−X still maintained good photocatalytic degradation activity of tetracycline after five cycles, and the structure of the catalyst did not change. The reaction mechanism related to the degradation of TC by photocatalytic reactions was explored in detail, and the photoexcitation of the semiconductor heterojunction, as well as the subsequent free radical reaction process and the degradation pathway of TC were clarified. This work provides a promising strategy for the preparation of efficient photocatalytic materials and the development of water purification technology. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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16 pages, 8685 KiB  
Article
Platinum-Modified Rod-like Titania Mesocrystals with Enhanced Photocatalytic Activity
by Zhishun Wei, Yuanyuan Ji, Zuzanna Bielan, Xin Yue, Yuqi Xu, Jiajie Sun, Sha Chen, Guoqiang Yi, Ying Chang and Ewa Kowalska
Catalysts 2024, 14(4), 283; https://doi.org/10.3390/catal14040283 - 22 Apr 2024
Cited by 5 | Viewed by 2076
Abstract
Photocatalysis is considered as an environmentally friendly method for both solar energy conversion and environmental purification of water, wastewater, air, and surfaces. Among various photocatalytic materials, titania is still the most widely investigated and applied, but more efforts must be carried out considering [...] Read more.
Photocatalysis is considered as an environmentally friendly method for both solar energy conversion and environmental purification of water, wastewater, air, and surfaces. Among various photocatalytic materials, titania is still the most widely investigated and applied, but more efforts must be carried out considering the synthesis of highly efficient photocatalysts for multifarious applications. It is thought that nanoengineering design of titania morphology might be the best solution. Accordingly, here, titania mesocrystals, assembled from crystallographically oriented nanocrystals, have been synthesized by an easy, cheap, and “green” solvothermal method (without the use of surfactants and templates), followed by simple annealing. The obtained materials have been characterized by various methods, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and diffuse reflectance spectroscopy (DRS). It has been found that the as-obtained photocatalysts exhibit a unique nanorod-like subunit structure with excellent crystalline and surface properties. However, pristine titania is hardly active for a hydrogen evolution reaction, and thus additional modification has been performed by platinum photodeposition (and silver as a reference). Indeed, the modification with only 2 wt% of noble metals results in a significant enhancement in activity, i.e., ca. 75 and 550 times by silver- and platinum-modified samples, respectively, reaching the corresponding reaction rates of 37 μmol h−1 and 276 μmol h−1. Additionally, titania mesocrystals exhibit high oxidation power under simulated solar light irradiation for the degradation of antibiotics within the tetracycline group (tetracycline (TC), ciprofloxacin (CIP), norfloxacin (NOR) and oxytetracycline hydrochloride (OTC)). It has been found that both experimental results and the density functional theory (DFT) calculations confirm the high ability of titania mesocrystals for oxidative decomposition of tetracycline antibiotics. Full article
(This article belongs to the Special Issue Novel Nanocatalysts for Sustainable and Green Chemistry)
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20 pages, 14829 KiB  
Article
Plasmonic Nanocomposites of ZnO-Ag Produced by Laser Ablation and Their Photocatalytic Destruction of Rhodamine, Tetracycline and Phenol
by Elena D. Fakhrutdinova, Anastasia V. Volokitina, Sergei A. Kulinich, Daria A. Goncharova, Tamara S. Kharlamova and Valery A. Svetlichnyi
Materials 2024, 17(2), 527; https://doi.org/10.3390/ma17020527 - 22 Jan 2024
Cited by 9 | Viewed by 2061
Abstract
Hydrosphere pollution by organic pollutants of different nature (persistent dyes, phenols, herbicides, antibiotics, etc.) is one of the urgent ecological problems facing humankind these days. The task of water purification from such pollutants can be effectively solved with the help of modern photocatalytic [...] Read more.
Hydrosphere pollution by organic pollutants of different nature (persistent dyes, phenols, herbicides, antibiotics, etc.) is one of the urgent ecological problems facing humankind these days. The task of water purification from such pollutants can be effectively solved with the help of modern photocatalytic technologies. This article is devoted to the study of photocatalytic properties of composite catalysts based on ZnO modified with plasmonic Ag nanoparticles. All materials were obtained by laser synthesis in liquid and differed by their silver content and preparation conditions, such as additional laser irradiation and/or annealing of produced powders. The prepared ZnO-Ag powders were investigated by electron microscopy, X-ray diffraction and UV-Vis spectroscopy. Photocatalytic tests were carried out with well- known test molecules in water (persistent dye rhodamine B, phenol and common antibiotic tetracycline) using LED light sources with wavelengths of 375 and 410 nm. The introduction of small concentrations (up to 1%) of plasmonic Ag nanoparticles is shown to increase the efficiency of the ZnO photocatalyst by expanding its spectral range. Both the preparation conditions and material composition were optimized to obtain composite photocatalysts with the highest efficiency. Finally, the operation mechanisms of the material with different distribution of silver are discussed. Full article
(This article belongs to the Special Issue Obtaining and Characterization of New Materials, Volume IV)
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17 pages, 11828 KiB  
Article
A Streamlined Method to Obtain Biologically Active TcdA and TcdB Toxins from Clostridioides difficile
by Diane Sapa, Anaïs Brosse, Héloïse Coullon, Gauthier Péan de Ponfilly, Thomas Candela and Alban Le Monnier
Toxins 2024, 16(1), 38; https://doi.org/10.3390/toxins16010038 - 11 Jan 2024
Cited by 2 | Viewed by 2572
Abstract
The major virulence factors of Clostridioides difficile (C. difficile) are enterotoxins A (TcdA) and B (TcdB). The study of toxins is a crucial step in exploring the virulence of this pathogen. Currently, the toxin purification process is either laborious and time-consuming [...] Read more.
The major virulence factors of Clostridioides difficile (C. difficile) are enterotoxins A (TcdA) and B (TcdB). The study of toxins is a crucial step in exploring the virulence of this pathogen. Currently, the toxin purification process is either laborious and time-consuming in C. difficile or performed in heterologous hosts. Therefore, we propose a streamlined method to obtain functional toxins in C. difficile. Two C. difficile strains were generated, each harboring a sequence encoding a His-tag at the 3′ end of C. difficile 630∆erm tcdA or tcdB genes. Each toxin gene is expressed using the Ptet promoter, which is inducible by anhydro-tetracycline. The obtained purification yields were 0.28 mg and 0.1 mg per liter for rTcdA and rTcdB, respectively. In this study, we successfully developed a simple routine method that allows the production and purification of biologically active rTcdA and rTcdB toxins with similar activities compared to native toxins. Full article
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20 pages, 4937 KiB  
Article
Magnetic Carbon Quantum Dots/Iron Oxide Composite Based on Waste Rice Noodle and Iron Oxide Scale: Preparation and Photocatalytic Capability
by Wanying Ying, Qing Liu, Xinyan Jin, Guanzhi Ding, Mengyu Liu, Pengyu Wang and Shuoping Chen
Nanomaterials 2023, 13(18), 2506; https://doi.org/10.3390/nano13182506 - 6 Sep 2023
Cited by 9 | Viewed by 2283
Abstract
To provide an economical magnetic photocatalyst and introduce an innovative approach for efficiently utilizing discarded waste rice noodle (WRN) and iron oxide scale (IOS), we initially converted WRN into carbon quantum dots (CQDs) using a hydrothermal method, simultaneously calcining IOS to obtain iron [...] Read more.
To provide an economical magnetic photocatalyst and introduce an innovative approach for efficiently utilizing discarded waste rice noodle (WRN) and iron oxide scale (IOS), we initially converted WRN into carbon quantum dots (CQDs) using a hydrothermal method, simultaneously calcining IOS to obtain iron oxide (FeOx). Subsequently, we successfully synthesized a cost-effective, magnetic CQDs/FeOx photocatalytic composite for the first time by combining the resulting CQDs and FeOx. Our findings demonstrated that calcining IOS in an air atmosphere enhanced the content of photocatalytically active α-Fe2O3, while incorporating WRN-based CQDs into FeOx improved the electron-hole pair separation, resulting in increased O2 reduction and H2O oxidation. Under optimized conditions (IOS calcination temperature: 300 °C; carbon loading: 11 wt%), the CQDs/FeOx composite, utilizing WRN and IOS as its foundation, exhibited exceptional and reusable capabilities in photodegrading methylene blue and tetracycline. Remarkably, for methylene blue, it achieved an impressive degradation rate of 99.30% within 480 min, accompanied by a high degradation rate constant of 5.26 × 10−3 min−1. This composite demonstrated reusability potential for up to ten photocatalytic cycles without a significant reduction in the degradation efficiency, surpassing the performance of IOS and FeOx without CQDs. Notably, the composite exhibited strong magnetism with a saturation magnetization strength of 34.7 emu/g, which enables efficient and convenient recovery in photocatalytic applications. This characteristic is highly advantageous for the large-scale industrial utilization of photocatalytic water purification. Full article
(This article belongs to the Special Issue Semiconductor Quantum Dots: Synthesis, Properties and Applications)
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15 pages, 5005 KiB  
Article
Reactive Ceramic Membrane for Efficient Micropollutant Purification with High Flux by LED Visible-Light Photocatalysis: Device Level Attempts
by Shuo Li, Xuan Zhang, Rui Fang, Zhiliang Cheng, Qian Xu, Shu Ma, Jie Xiong, Peng Chen and Guangjie Feng
Crystals 2023, 13(4), 651; https://doi.org/10.3390/cryst13040651 - 10 Apr 2023
Cited by 1 | Viewed by 2118
Abstract
Micropollutants (MPs) are widely occurring in surface water all over the world with extremely low concentrations, and their treatment requires high energy consumption and efficiency. In this study, a large-sized planar photocatalytic reactive ceramic membrane (PRCM) was prepared using the facile dip-coating method [...] Read more.
Micropollutants (MPs) are widely occurring in surface water all over the world with extremely low concentrations, and their treatment requires high energy consumption and efficiency. In this study, a large-sized planar photocatalytic reactive ceramic membrane (PRCM) was prepared using the facile dip-coating method with nitrogen-doped TiO2 (N-TiO2-CM) for the purification of tetracycline hydrochloride (TC) as a model MP. The N-TiO2 nanoparticles and the as-prepared N-TiO2-CM were characterized by SEM/EDS, TEM, XPS, UV–Vis DRS, and FT-IR. A fixed bed reactor integrated N-TiO2-CM, and visible LED light was fabricated for the new PRCM water treatment system for the removal of TC with a comprehensive consideration of the degradation rate and permeate flux. The SEM/EDS results indicated that the N-TiO2 was uniformly and tightly loaded onto the flat CM, and the pure water flux could reach over 2000 L/(m2 × h) under a trans-membrane pressure (TMP) of −92 kPa. The fixed bed PRCM water treatment system is extremely suited for MP purification, and the removal efficiency of TC was as high as 92% with 270 min even though its initial concentration was as low as 20 mg/L. The degradation rate and permeate flux of N-TiO2-CM was 2.57 and 2.30 times as high as that of the CM, indicating its good self-cleaning characteristics. The quenching experiments illustrated that the reactive radicals involved in the PRCM process, •OH and •O2, were responsible for TC degradation. This research also provides a utilization proposal for a scale-up N-TiO2-CM system for water and wastewater treatment. Full article
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18 pages, 16982 KiB  
Article
Different Strategies for the Microfluidic Purification of Antibiotics from Food: A Comparative Study
by Lorenzo Lunelli, Martina Germanis, Lia Vanzetti and Cristina Potrich
Biosensors 2023, 13(3), 325; https://doi.org/10.3390/bios13030325 - 27 Feb 2023
Cited by 3 | Viewed by 2634
Abstract
The presence of residual antibiotics in food is increasingly emerging as a worrying risk for human health both for the possible direct toxicity and for the development of antibiotic-resistant bacteria. In the context of food safety, new methods based on microfluidics could offer [...] Read more.
The presence of residual antibiotics in food is increasingly emerging as a worrying risk for human health both for the possible direct toxicity and for the development of antibiotic-resistant bacteria. In the context of food safety, new methods based on microfluidics could offer better performance, providing improved rapidity, portability and sustainability, being more cost effective and easy to use. Here, a microfluidic method based on the use of magnetic microbeads specifically functionalized and inserted in polymeric microchambers is proposed. The microbeads are functionalized either with aptamers, antibodies or small functional groups able to interact with specific antibiotics. The setup of these different strategies as well as the performance of the different functionalizations are carefully evaluated and compared. The most promising results are obtained employing the functionalization with aptamers, which are able not only to capture and release almost all tetracycline present in the initial sample but also to deliver an enriched and simplified solution of antibiotic. These solutions of purified antibiotics are particularly suitable for further analyses, for example, with innovative methods, such as label-free detection. On the contrary, the on-chip process based on antibodies could capture only partially the antibiotics, as well as the protocol based on beads functionalized with small groups specific for sulfonamides. Therefore, the on-chip purification with aptamers combined with new portable detection systems opens new possibilities for the development of sensors in the field of food safety. Full article
(This article belongs to the Special Issue Microfluidics for Biomedical Applications (2nd Edition))
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15 pages, 5527 KiB  
Article
Photocatalytic Degradation of Tetracycline by Supramolecular Materials Constructed with Organic Cations and Silver Iodide
by Xing-Xing Zhang, Xiao-Jia Wang and Yun-Yin Niu
Catalysts 2022, 12(12), 1581; https://doi.org/10.3390/catal12121581 - 5 Dec 2022
Cited by 21 | Viewed by 2925
Abstract
Photocatalytic degradation, as a very significant advanced oxidation technology in the field of environmental purification, has attracted extensive attention in recent years. The design and synthesis of catalysts with high-intensity photocatalytic properties have been the focus of many researchers in recent years. In [...] Read more.
Photocatalytic degradation, as a very significant advanced oxidation technology in the field of environmental purification, has attracted extensive attention in recent years. The design and synthesis of catalysts with high-intensity photocatalytic properties have been the focus of many researchers in recent years. In this contribution, two new supramolecular materials {[(L1)·(Ag4I7)]CH3CN} (1), {[(L2)·(Ag4I7)]CH3CN} (2) were synthesized by solution volatilization reaction of two cationic templates 1,3,5-Tris(4-aminopyridinylmethyl)-2,4,6-Trimethylphenyl bromide (L1) and 1,3,5-Tris(4-methyl pyridinyl methyl)-2,4,6-trimethylphenyl bromide (L2) with metal salt AgI at room temperature, respectively. The degradation effect of 1 and 2 as catalyst on tetracycline (TC) under visible light irradiation was studied. The results showed that the degradation of TC by 1 was better than that by 2 and both of them had good stability and cyclability. The effects of pH value, catalyst dosage, and anion in water on the photocatalytic performance were also investigated. The adsorption kinetics fit the quasi-first-order model best. After 180 min of irradiation with 1, the degradation rate of TC can reach 97.91%. In addition, the trapping experiments showed that ·OH was the main active substance in the photocatalytic degradation of TC compared with ·O2 and h+. Because of its simple synthesis and high removal efficiency, catalyst 1 has potential value for the treatment of wastewater containing organic matter. Full article
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