Search Results (771)

The continuous occurrence of steroidal pharmaceutical dexamethasone (DXM) in aqueous environments indicates the need for an efficient removal technology. The frequent detection of DXM in surface water could be substantially reduced by the application of photo-induced advanced oxidation technology. In the present study, Fe²⁺ and UVA-light activated peroxo compounds were applied for the degradation and mineralization of a glucocorticoid, 25.5 µM DXM, in ultrapure water (UPW). The treatment efficacies were validated in real spring water (SW). A 120 min target pollutant degradation followed pseudo first-order reaction kinetics when an oxidant/Fe²⁺ dose 10/1 or/and UVA irradiation were applied. Acidic conditions (a pH of 3) were found to be more favorable for DXM oxidation (≥99%) regardless of the activated peroxo compound. Full conversion of DXM was not achieved, as the maximum TOC removal reached 70% in UPW by the UVA/H₂O₂/Fe²⁺ system (molar ratio of 10/1) at a pH of 3. The higher efficacy of peroxymonosulfate-based oxidation in SW could be induced by chlorine, bicarbonate, and carbonate ions; however, it is not applicable for peroxydisulfate and hydrogen peroxide. Overall, consistently higher efficacies for HO^•-dominated oxidation systems were observed. The findings from the current paper could complement the knowledge of oxidative removal of low-level DXM in real water matrices. Full article

Nanofiltration (NF) is considered a competitive purification method for acidic stream treatments. However, conventional thin-film composite NF membranes degrade under acid exposures, limiting their applications in industrial acid treatment. For example, wet-process phosphoric acid contains impurities of multivalent metal ions, but NF membrane technologies for impurity removal under harsh conditions are still immature. In this work, we develop a novel strategy of acid-resistant nanofiltration membranes based on interfacial polymerization (IP) of polyethyleneimine (PEI) and cyanuric chloride (CC) with the s-triazine ring. The IP process was optimized by orthogonal experiments to obtain positively charged PEI-CC membranes with a molecular weight cut-off (MWCO) of 337 Da. We further applied it to the approximate industrial phosphoric acid purification condition. In the tests using a mixed solution containing 20 wt% P₂O₅, 2 g/L Fe³⁺, 2 g/L Al³⁺, and 2 g/L Mg²⁺ at 0.7 MPa and 25 °C, the NF membrane achieved 56% rejection of Fe, Al, and Mg and over 97% permeation of phosphorus. In addition, the PEI-CC membrane exhibited excellent acid resistance in the 48 h dynamic acid permeation experiment. The simple fabrication procedure of PEI-CC membrane has excellent acid resistance and great potential for industrial applications. Full article

Untreated sewage sludge (SS) and misused stabilization technologies have contributed to great contamination and the accumulation of various pollutants in agricultural soils. Regarding micro-pollutants’ degradation, scalable and effective technologies are still scarce. Although many attempts at composting adaptations have been discussed, only a few have been tested individually under outdoor conditions. To investigate different composting methods (bioaugmentation and semipermeable cover) for the removal of micro-pollutants frequently found in SS, we performed a set of on-site experiments. Windrows of SS and olive pruning were used as the compostable material and were subjected to (i) bioaugmentation with the fungus Penicillium oxalicum, (ii) covered composting, (iii) covered and bioaugmented composting, and (iv) a conventional composting pile, which was included as a control. The entire experiment lasted 99 days. Bioaugmentation without cover increased the phosphorus content, favored a reduction in heavy metal content, and was the only treatment that reduced carbamazepine at the end of the process. Moreover, the inoculation of P. oxalicum under semipermeable cover increased the richness, diversity, and dominance of specific microbial taxa and total bacterial abundance. The four mature composts obtained met the standards required to be classified in the B fertilizer category, showing that we reduced most of the micro-pollutants, and passed the germination test. Full article

Sorghum halepense (L.) Pers. (common name Johnson grass) is a perennial invasive weed that causes great harm worldwide, and its allelopathy has been demonstrated in a series of experiments. The present study offers new insights into its organ-specific phytochemical profiles using state-of-the-art metabolomic technology and explores the effects of a methanol extract of S. halepense rhizomes (ShER) and its major bioactive compounds (p-hydroxybenzoic acid and chlorogenic acid) on three noxious weed species. The phytotoxic effects of ShER are reflected through the inhibition of seed germination and reduced seedling growth, which are accompanied by changes in the antioxidant system of seedlings. Phytotoxicity is species specific and concentration dependent, and it is more pronounced against Chenopodiastrum murale (L.) S. Fuentes, Uotila & Borsch and Datura stramonium L. than highly tolerant Amaranthus retroflexus L. Catalase (CAT) is most likely the major mediator in the removal of reactive oxygen species, which are generated during germination and early seedling growth of Ch. murale exposed to ShER. The results of the present study imply the high potential of ShER in the management of amaranthaceous and solanaceous weeds, such as Ch. murale and D. stramonium, respectively. The present study offers an environmentally friendly solution for the biological control of weeds belonging to the families Amaranthaceae and Solanaceae. Also, the results of this research highlight the possibility of effective management of S. halepense by using it as a feedstock for bioherbicide production. Full article

Calorific value and moisture content are the key indices to evaluate Caragana pellet fuel’s quality and combustion characteristics. Calorific value is the key index to measure the energy released by energy plants during combustion, which determines energy utilization efficiency. But at present, the determination of solid fuel is still carried out in the laboratory by oxygen bomb calorimetry. This has seriously hindered the ability of large-scale, rapid detection of fuel particles in industrial production lines. In response to this technical challenge, this study proposes using hyperspectral imaging technology combined with various chemometric methods to establish quantitative models for determining moisture content and calorific value in Caragana korshinskii fuel. A hyperspectral imaging system was used to capture the spectral data in the 935–1720 nm range of 152 samples from multiple regions in Inner Mongolia Autonomous Region. For water content and calorific value, three quantitative detection models, partial least squares regression (PLSR), random forest regression (RFR), and extreme learning machine (ELM), respectively, were established, and Monte Carlo cross-validation (MCCV) was chosen to remove outliers from the raw spectral data to improve the model accuracy. Four preprocessing methods were used to preprocess the spectral data, with standard normal variate (SNV) preprocessing performing best on the quantitative moisture content detection model and Savitzky–Golay (SG) preprocessing performing best on the calorific value detection method. Meanwhile, to improve the prediction accuracy of the model to reduce the redundant wavelength data, we chose four feature extraction methods, competitive adaptive reweighted sampling (CARS), successive pojections algorithm (SPA), genetic algorithm (GA), iteratively retains informative variables (IRIV), and combined the three models to build a quantitative detection model for the characteristic wavelengths of moisture content and calorific value of Caragana korshinskii fuel. Finally, a comprehensive comparison of the modeling effectiveness of all methods was carried out, and the SNV-IRIV-PLSR modeling combination was the best for water content prediction, with its prediction set determination coefficient $\left(R_P^2\right)$, root mean square error of prediction (RMSEP), and relative percentage deviation (RPD) of 0.9693, 0.2358, and 5.6792, respectively. At the same time, the moisture content distribution map of Caragana fuel particles is established by using this model. The SG-CARS-RFR modeling combination was the best for calorific value prediction, with its $R_P^2$, RMSEP, and RPD of 0.8037, 0.3219, and 2.2864, respectively. This study provides an innovative technical solution for Caragana fuel particles’ value and quality assessment. Full article

The increasing presence of ECs in aquatic environments has drawn significant attention to the need for innovative, accessible, and sustainable solutions in wastewater treatment. This review provides a comprehensive overview of the use of agricultural residues—often discarded and undervalued—as raw materials for the development of efficient bioadsorbents. Based on a wide range of recent studies, this work presents various types of materials, such as rice husks, sugarcane bagasse, and açaí seeds, that can be transformed through thermal and chemical treatments into advanced bioadsorbents capable of removing pharmaceuticals, pesticides, dyes, and in some cases, even addressing highly persistent pollutants such as PFASs. The main objectives of this review are to (1) assess agricultural-residue-derived bioadsorbents for the removal of ECs; (2) examine physical and chemical modification techniques that enhance adsorption performance; (3) evaluate their scalability and applicability in real-world treatment systems. The review also highlights key adsorption mechanisms—such as π–π interactions, hydrogen bonding, and ion exchange—alongside the influence of parameters like pH and ionic strength. The review also explores the kinetic, isothermal, and thermodynamic aspects of the adsorption processes, highlighting both the efficiency and reusability potential of these materials. This work uniquely integrates microwave-assisted pyrolysis, magnetic functionalization, and hybrid systems, offering a roadmap for sustainable water remediation. Finally, comparative performance analyses, applications using real wastewater, regeneration strategies, and the integration of these bioadsorbents into continuous treatment systems are presented, reinforcing their promising role in advancing sustainable water remediation technologies. Full article

This study investigated the degradation efficacy, kinetics, and mechanism of the ozone (O₃) process and two enhanced O₃ processes (O₃/peroxymonosulfate (O₃/PMS) and O₃/peroxymonosulfate/iron molybdates/biochar composite (O₃/PMS/FeMoBC)), especially the O₃/PMS/FeMoBC process, for the degradation of tetracycline (TC) in water. An FeMoBC sample was synthesized by the impregnation–pyrolysis method. The XRD results showed that the material loaded on BC was an iron molybdates composite, in which Fe₂Mo₃O₈ and FeMoO₄ accounted for 26.3% and 73.7% of the composite, respectively. The experiments showed that, for the O₃/PMS/FeMoBC process, the optimum conditions were obtained at pH 6.8 ± 0.1, an initial concentration of TC of 0.03 mM, an FeMoBC dosage set at 200 mg/L, a gaseous O₃ concentration set at 3.6 mg/L, and a PMS concentration set at 30 μM. Under these reaction conditions, the degradation rate of TC in 8 min and 14 min reached 94.3% and 98.6%, respectively, and the TC could be reduced below the detection limit (10 μg/L) after 20 min of reaction. After recycling for five times, the degradation rate of TC could still reach about 40%. The introduction of FeMoBC into the O₃/PMS system significantly improved the TC degradation efficacy and resistance to inorganic anion interference. Meanwhile, it enhanced the generation of hydroxyl radicals (^•OH) and sulfate radicals (SO₄^•−), thus improving the oxidizing efficiency of TC in water. Material characterization analysis showed that FeMoBC has a well-developed porous structure and abundant active sites, which is beneficial for the degradation of pollutants. The reaction mechanism of the O₃/PMS/FeMoBC system was speculated by the EPR technique and quenching experiments. The results showed that FeMoBC efficiently catalyzed the O₃/PMS process to generate a variety of reactive oxygen species, leading to the efficient degradation of TC. There are four active oxidants in O₃/PMS/FeMoBC system, namely ^•OH, SO₄^•−, ¹O₂, and •O₂⁻. The order of their contribution importance was ^•OH, ¹O₂, SO₄^•−, and •O₂⁻. This study provides an effective technological pathway for the removal of refractory organic matter in the aquatic environment. Full article

Chemical products, including cleaning agents, disinfectants, stain removers, and cosmetics, release harmful chemicals that pose a risk to human health and the environment, necessitating alternative sources. The objective of this research was to identify the most effective phytoextract from food production waste for use in sustainable aerosol hygiene technology as an electrostatic bio-disinfectant. The investigation was performed through wipe tests and airborne microbial collection techniques. The upgraded coffee silverskin phytoextract demonstrated superior disinfection potential for various surfaces and airborne microbes compared to the hot trub phytoextract, with an industrial disinfectant serving as the control. Log reduction analyses revealed a more significant killing efficacy (p ≤ 0.05, using the ANOVA test) against Gram-positive organisms (Bacillus subtilis and Listeria monocytogenes) than against Gram-negative organisms (Escherichia coli and Vibrio parahaemolyticus), with the log reductions ranging from 3.08 to 5.56 and 3.72 to 5.81, respectively. Chemical characterization by LC-ESI-QTOF-MS, ¹H NMR, and FTIR showed that CGAs and chalcones are the most bioactive compounds in CSS and HT, respectively. The innovation in this work involves an integrated approach that combines waste-derived phytoextracts, advanced chemical profiling, and scalable aerosol disinfection. Furthermore, this research offers a greener, cost-effective, and industrially relevant alternative to synthetic chemical disinfectants. The interdisciplinary approach contributes to the development of bio-based disinfectants for use in the food industry, hospitals, and public health settings. This investigation supports a paradigm shift toward sustainable disinfection practices, thereby improving food and environmental safety. Full article

The extensive use of herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA), coupled with its limited biodegradability, has led to its ubiquitous presence in aquatic environments. This work investigates the removal of MCPA (100 mg/L) in the aqueous phase via solar photo-Fenton. The process was carried out in a 700 mL reactor using a Xe lamp that simulates solar radiation (λ: 250–700 nm). A parametric study was conducted to assess the influence of dissolved O₂ on the reaction medium, Fe²⁺ dosage, H₂O₂ concentration and pH₀. The results indicate that dissolved O₂ boosts pollutant mineralization, even working at sub-stoichiometric H₂O₂ concentrations. Under optimal reaction conditions ([Fe²⁺]: 7.5 mg/L, [H₂O₂]₀: 322 mg/L (stoichiometric dose), pH₀: 3.5), the MCPA reached almost complete mineralization (X_TOC: 98.40%) in 180 min. Phytotoxicity and ecotoxicity assessments of treated effluents revealed that even working at sub-stoichiometric H₂O₂ dosages, toxicity decreases with the solar photo-Fenton treatment. Finally, the solar photo-Fenton process was evaluated in relevant matrices (river water and WWTP secondary effluent) and a realistic pollutant concentration (100 µg/L). In all cases, the pollutant degradation was ≥70% in 60 min, demonstrating the potential of this technology as a tertiary treatment. Full article

Rare earth elements (REEs) have garnered significant global attention due to their essential role in advanced technologies. Sri Lanka is endowed with various REE-bearing minerals, including the apatite-rich deposit in the Eppawala area, commonly known as Eppawala rock phosphate (ERP). However, direct extraction of REEs from ERP is technically challenging and economically unfeasible. This study introduces a novel, integrated approach for recovering REEs from ERP as a by-product of nitrophosphate fertilizer production. The process involves nitric acid-based acidolysis of apatite, optimized at 10 M nitric acid for 2 h at 70 °C with a pulp density of 2.4 mL/g. During cooling crystallization, 42 wt% of calcium was removed as Ca(NO₃)₂.4H₂O while REEs remained in the solution. REEs were then selectively precipitated as REE phosphates via pH-controlled addition of ammonium hydroxide, minimizing the co-precipitation with calcium. Further separation was achieved through selective dissolution in a sulfuric–phosphoric acid mixture, followed by precipitation as sodium rare earth double sulfates. The process achieved over 90% total REE recovery with extraction efficiencies in the order of Pr > Nd > Ce > Gd > Sm > Y > Dy. Samples were characterized for their phase composition, elemental content, and morphology. The fertilizer results confirmed the successful production of a nutrient-rich nitrophosphate (NP) with 18.2% nitrogen and 13.9% phosphorus (as P₂O₅) with a low moisture content (0.6%) and minimal free acid (0.1%), indicating strong agronomic value and storage stability. This study represents one of the pioneering efforts to valorize Sri Lanka’s apatite through a novel, dual-purpose, and circular approach, recovering REEs while simultaneously producing high-quality fertilizer. Full article

A 56-day trial was conducted to assess the effects of rice straw (RS) and bamboo flour (BF) on growth performance, water quality, gill histology, and the bacterial community of water and the intestine of mandarin fish (Siniperca chuatsi) in biofloc technology systems. The results showed that mandarin fish in the RS and BF groups had comparable survival rates of 100.00 ± 0.00 and 93.33 ± 3.85%; feed conversion ratios of 1.13 ± 0.02 and 1.40 ± 0.15; and weight gain rates of 112.21 ± 1.56 and 100.92 ± 6.45%, respectively. From days 11 to 56 of the farming period, the BF group was more effective than the RS group in removing total ammonia nitrogen (TAN) and NO₂⁻-N, maintaining TAN levels below 0.24 ± 0.05 mg/L. During the early stage of the experiment, the TAN level in the RS group was higher; however, with the supplementation of a carbon source, it gradually decreased and eventually stabilized at 0.13 ± 0.03 mg/L later in the farming period. The secondary gill lamella in the RS group was curved and showed hyperplasia, and the basal gill lamellae showed an increase in the volume of interlamellar cell mass in the BF group. Genes related to denitrification (narG, napA, nirS, nirK, and nosZ) and anammox showed higher expression levels in the BF group than in the RS group, although the differences were not statistically significant (p > 0.05). The results of 16S rRNA sequencing research showed that both treatment groups’ intestinal and water bacterial communities had comparable levels of richness and diversity. Pseudomonas mosselii was the dominant bacterial species in the water. In the BF group, the dominant intestinal species were Bacillus halodurans and Caldalkalibacillus thermarum, while in the RS group, the dominant species was Plesiomonas shigelloides. In conclusion, rice straw and bamboo flour are applicable in BFT systems for mandarin fish culture, with good growth performance and water quality. The BF group showed higher nitrogen removal efficiency and denitrification gene expression than the RS group. Full article

Spent automobile catalysts can be an important source of platinum for industry applications. Low-cost and simple technologies for platinum recovery from this source are sought, especially involving the application of green adsorbents. Honeycomb biowaste can be an excellent candidate for this purpose; n-hexane-treated honeycomb biowaste is therefore obtained for the first time. This material is characterized using several instrumental techniques, confirming the presence of O, N, and P heteroatoms on its surface and the complex morphology of its particles. The maximum static Pt(II)/Pt(IV) adsorption (46 mg/g and 60 mg/g, respectively) onto the n-hexane-extracted honeycomb biomass is reached at pH = 1.55 and a contact time of 50 h. The adsorption kinetics are best fitted to the pseudo-second-order model in both cases. The Langmuir model best described the Pt(II)/Pt(IV) adsorption isotherms on the studied material. Quantitative desorption of the Pt from the studied material is reached for 1 mol/L thiourea dissolved in HCl. The adsorption mechanism of Pt(IV) ions onto the obtained material is based mainly on the surface complexation reactions. The studied material is successfully applied for the first time for Pt(IV) removal from a spent automobile catalyst leachate. Full article

This study investigates an innovative soil washing process designed to remediate arsenic (As) contamination in sulfuric acid (H₂SO₄) plant soil by using discarded H₂SO₄ solution in situ. The pilot-scale process comprises five key steps: screening and rinsing of oversized sand, washing the soil with H₂SO₄, phase separation, recycling the washing solution, and water recovery. This research explored the optimal washing parameters for the process and further researched the reuse of the H₂SO₄ solution across multiple batches. The pH of the washing solution, critical at a threshold of 6.5, was identified as a key factor for effective recycling. Approximately 75% of the H₂SO₄ solution was successfully recycled. In terms of economic analysis, the total operational cost of the soil washing process was significantly lower than in previous studies. Overall, these findings demonstrate the feasibility of using discarded H₂SO₄ as a washing agent for As-contaminated soil. The integration of automated pH-based monitoring technology streamlines the washing process, providing a cost-effective and effective As removal remediation strategy, making it a viable option for large-scale applications in soil remediation. Full article

The disposal of wastewater resulting from petroleum industries presents a major environmental challenge due to the presence of hard-to-degrade organic pollutants, such as oils and hydrocarbons, and high chemical oxygen demand (COD). In this study, an efficient and eco-friendly method was developed to treat such wastewater using a photocatalyst composed of biochar derived from pistachio shells and loaded with zinc oxide (ZnO) nanoparticles. The biochar-ZnO composite was prepared via a co-precipitation-assisted pyrolysis method to evaluate its efficiency in the photocatalytic degradation of petroleum wastewater (PW). The synthesized material was characterized using various techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy, to determine surface morphology, crystal structure, and functional groups present on the catalyst surface. Photocatalytic degradation experiments were conducted under UV and sunlight for 90 h of irradiation to evaluate the performance of the proposed system in removing oil and reducing COD levels. Key operational parameters, such as pH (2–10), catalyst dosage (0–0.1) g/50 mL, and oil and COD concentrations (50–500) ppm and (125–1252) ppm, were optimized by response surface methodology (RSM) to obtain the maximum oil and COD removal efficiency. The oil and COD were removed from PW (90.20% and 88.80%) at 0.1 g/50 mL of PS/ZnO, a pH of 2, and 50 ppm oil concentration (125 ppm of COD concentration) under UV light. The results show that pollutant removal is slightly better when using sunlight (80.00% oil removal, 78.28% COD removal) than when using four lamps of UV light (77.50% oil removal, 75.52% COD removal) at 0.055 g/50 mL of PS/ZnO, a pH of 6.8, and 100 ppm of oil concentration (290 ppm of COD concentration). The degradation rates of the PS/ZnO supported a pseudo-first-order kinetic model with R² values of 0.9960 and 0.9922 for oil and COD. This work indicates the potential use of agricultural waste, such as pistachio shells, as a sustainable source for producing effective catalysts for industrial wastewater treatment, opening broad prospects in the field of green and nanotechnology-based environmental solutions in the development of eco-friendly and effective wastewater treatment technologies under solar light. Full article

Microalgae-based bioremediation is increasingly recognized as a sustainable, efficient, and straightforward technology. Despite this growing interest, the potential of Parachlorella hussii for metal biosorption remains underexplored. This study is the first report evaluating the metal biosorption activity in Parachlorella hussii ACOI 1508 (N9), highlighting the impact of the culture age on the monosaccharide composition and its correlation to the metal binding capacity. The capsular strain (N9) was isolated from the hypersaline ecosystem—Lake Chott Aïn El-Beida—in southeastern Algeria. Cultivated in Bold’s Basal medium, the strain produced 0.807 ± 0.059 g L⁻¹ of RPSs and 1.975 ± 0.120 g L⁻¹ of CPSs. Biochemical analysis of the extracts revealed a high total sugar content (% w/w) that ranged from 62.98 ± 4.87% to 95.60 ± 87% and a low protein content (% w/w) that ranged from 0.49 ± 0.08% to 1.35 ± 0.69%, with RPS-D7 and RPS-D14 having high molecular weight (≥2 MDa). HPLC-based monosaccharide characterization demonstrated compositional differences between the exponential and stationary phases, with rhamnose dominating (~55%) in RPS-D14 and with the presence of uronic acids comprising 7–11.3%. Metal removal efficiency was evaluated using the whole biomass in two growth phases. Copper uptake exhibited the highest capacity, reaching 18.55 ± 0.61 mg Cu g⁻¹ DW at D14, followed by zinc removal with 6.52 ± 0.61 mg Zn g⁻¹ DW. Interestingly, removal efficiencies increased to about twofold during the stationary phase, reaching 51.15 ± 1.14% for Cu, 51.08 ± 3.35% for Zn, and 36.55 ± 3.09% for Ni. The positive results obtained for copper/zinc removal highlight the biosorption potential of P. hussii, and notably, we found that the metal removal capacity significantly improved with culture age—a parameter that has been poorly investigated in prior studies. Furthermore, we observed a growth phase-dependent modulation in monosaccharide composition, which correlated with enhanced functional properties of the excreted biomolecules involved in biosorption. This metabolic adjustment suggests an adaptive response that may contribute to the species’ effectiveness in heavy metal uptake, underscoring its novelty and biotechnological relevance. Full article