Abstract In this work, the 2-fluoroterephthalic acid with asymmetric structure and high electronegative F species was introduced in the assembly of Ce-UiO-66 catalysts to increase the defect density and enlarge pore structure for enhancement in removal efficiency of sulfamethoxazole. Owing to the strong coordination ability from high electronegative F species of 2-fluoroterephthalic acid with Ce-oxo nodes, the designed CUF exhibited improved interfacial properties (accelerated electron transfer rate, available active sites and enhanced interaction with PMS), which was favorable for the exploration and accessibility of active sites with sulfamethoxazole and PMS to decrease the adsorption barrier and accelerate PMS activation. As a result, the CUF catalysts exhibited higher adsorption capacity (173.4 mg/g) than that of CUH (117.8 mg/g), the enhanced degradation efficiency of sulfamethoxazole with a rate constant higher than 2.3 times CUH, good elimination (>95 %) of methylene blue, tetracycline and ibuprofen. In addition, the CUF/PMS system possessed satisfactory stability in wide solution pH, recycling and real water and good potential application in continuous wastewater treatment based on the designed dynamic catalytic reactor. This work provided deep insight into the design of catalysts with high adsorption performance and degradation efficiency based on the structure–activity relationship. Keywords: Ce-UiO-66; 2-fluoroterephthalic acid; Electron-withdrawing group; Defect density; Structure-activity https://doi.org/10.1016/j.cej.2024.156624

Unveiling the influence of precursor concentrations and biochar dosage for the solar photocatalysis of 1,3-diphenylguanidine in secondary municipal effluent. Abstract In this work, engineered hierarchal structures of biochar-supported bismuth tungstate are synthesized for wastewater treatment applications. The integration of biochar supports resulted in an increase in the surface area, reduction in crystallite size, and exposure of the active facets of Bi2WO6. Controlled Bi2WO6 morphologies were obtained by varying the precursor concentrations, causing a remarkable transition from mixed microspheres to flower-like structures and, ultimately, to nanosheets. The optimal composite demonstrated its efficiency in a spiked wastewater secondary effluent, achieving 97.74 % degradation of 1,3-diphenylguanidine (DPG) under 8 h of simulated solar light irradiation. The treatment also reduced the toxicity and COD of the spiked secondary effluent matrix. The primary reactive oxygen species detected were O2•– and h+. Additionally, the photocatalytic degradation mechanism and possible degradation by-products of DPG were identified. These results highlight the significant influence of the biochar supports and synthesis parameters on the activity of biochar-supported photocatalysts, paving the way for the design of superior photocatalyst materials for wastewater treatment applications. Keywords: Bismuth tungstate; Biochar; Heterogeneous photocatalysis; Tire wear particles; Secondary effluent https://doi.org/10.1016/j.cej.2024.149142

Abstract Sustainable methods for wastewater treatment offer promising solutions to address pressing environmental challenges. This study investigates the potential of graphitic carbon nitride (g-C3N4 ) as an environmentally friendly photocatalyst for wastewater treatment. The research involves the systematic exploration of various precursors (melamine, urea, and dicyanamide), different polymerization temperatures (500, 550, and 600 °C), and varying K-doping levels (1 %, 3 %, and 5 % KOH), providing valuable insights into the properties of g-C3N4. This study marks a significant advancement by reporting, for the first time, the successful degradation of 1,3-Diphenylguanidine (DPG) in wastewater. UCN-K1, a urea-derived g-C3N4 doped with 1 % KOH, displayed exceptional performance, achieving nearly 95 % DPG removal within 6 h under solar radiation and utilizing a remarkably low dose (0.1 g/L). Furthermore, the research offers a comprehensive understanding of reaction kinetics, a detailed analysis of K-doping effects, and profound insights into the degradation mechanism of DPG, including potential transformation products. Keywords: Graphitic carbon nitride; Solar photocatalytic degradation; Wastewater treatment; Tire wear particles https://doi.org/10.1016/j.cej.2024.150665

Abstract The potential environmental impacts of commonly employed antiviral drugs and their byproducts have attracted attention but remain largely unexplored. In this study, ozone (O3) was used to remove the oseltamivir phosphate (OP), a widely used antiviral, from different water matrices, including secondary municipal wastewater effluent (WWE). Over 90 % of OP was removed from a buffer solution using 10 µM of O3 in a short reaction time (30 s), while pseudo-first-order kinetics constants (K) showed a strong linear relationship with the initial O3 dosage. The pH of the solution was found to be an important factor in the ozonation process since the degradation mechanisms and, thereby, the K values are affected by the structural conformations of OP (protonated or deprotonated forms), the generation of hydroxyl radicals (•OH) under mild basic conditions, and the depletion of O3 under extreme basic pH. In addition, common inorganic ions slightly affect the K values, but increasing the ionic strength negatively influences the degradation process. Organic components in WWE also reduced the efficiency; however, over 95 % of OP degradation was achieved using a ratio of O3 dosage to dissolved organic carbon (DOC) of 0.544 g O3 g–1 DOC. Finally, a degradation pathway was proposed based on the detection of byproducts formed by direct ozonation and hydroxylation reactions. Acute toxicity and genotoxicity assessments on ozonated matrices, especially the WWE sample, suggest that these byproducts have no potential toxic effects. All these findings strongly suggest that ozonation can effectively degrade antivirals in municipal effluents. Keywords: Antiviral oseltamivir; Ozonation; Matrix effects; Degradation byproducts; Genotoxicity https://doi.org/10.1016/j.jece.2024.114297

Abstract 1T-MoS2 is a promising material for regulating the electronic structure of Fe-based catalyst to enhance PMS activation, due to the higher chemical reactivity of the basal plane with excellent intrinsic electronic properties. Herein, an excellent MoS2@Fe3O4 by using 1T- MoS2 as support to tune electronic structure, labeling as 1T-MoS2@Fe3O4, was successfully synthesized for faster and enhanced micropollutants degradation via Fenton-like peroxomonosulfate (PMS) activation. The composite showed remarkable catalytic performance, as evidenced by a removal rate of 1.12 × 10−1 min−1 for caffeine, which was 4.50 times higher than that of 2H-MoS2@Fe3O4, attributed to the robust capacity for Fe (II) regeneration. The efficiency of the 1T-MoS2@Fe3O4/PMS system was affected by pH, PMS and catalyst dosages, as well as water chemistry. Additionally, the potential mechanism for PMS activation was explored, showing that O2•single bond were the dominant reactive oxygen species (ROS) generated in the system due to the electron-rich O sites on the composite, and electron transfer processes play an important role during PMS activation. The Mo (IV) active sites facilitated accelerated Fe (III)/Fe (II) cycle, which promoted the rapid PMS activation. Excellent degradation of micropollutants (MPs) mixture in real secondary effluent was achieved by 1T-MoS2@Fe3O4/PMS system. The possible degradation pathways of caffeine (CAF), ibuprofen (IBP), and carbamazepine (CBZ) were also investigated. This study offers a new perspective on MoS2 as a co-catalyst/support within Fenton-like system. Keywords: 1T-MoS2@Fe3O4; Micropollutants degradation; Reactive oxygen species; Electron transfer; Electron-rich oxygen sites https://doi.org/10.1016/j.jece.2024.114944

Abstract Graphitic carbon nitride (g-C3N4) is a promising photocatalyst for solar-driven degradation of contaminants of emerging concern (CECs). However, its powdered form complicates recovery for large-scale applications in water treatment. In this study, we developed potassium-doped g-C3N4 (KCN) supported on expanded perlite (EP), a non-toxic volcanic glass, to address these recovery challenges. KCN was synthesized in situ by adding varying amounts of KOH to urea and EP, followed by calcination. The EP/KCN composites were characterized and tested for the degradation of 1,3-diphenyl guanidine (DPG), a tire wear pollutant. SEM images showed that KCN coverage increased with higher urea loading on EP, with EP/KCN20 (20:1 urea to EP, 1 wt% KOH) having nearly complete surface coverage. FT-IR spectra confirmed stronger C-N and C=N stretching vibrations with increased KCN content, confirming the successful incorporation of KCN into the composite. XRD patterns displayed distinct KCN peaks at higher loadings, while PL analysis suggested slightly reduced charge recombination in the EP/KCN20 composite, indicating enhanced photocatalytic efficiency. Furthermore, EP/KCN20 achieved 96.1 % degradation of DPG under simulated solar exposure in 5 h, with over 80 % efficiency maintained across four consecutive cycles. The composite also demonstrated robust performance under more complex conditions, including natural solar light and in DPG-spiked secondary municipal wastewater, with a cost of 5.57 USD/m3. These findings highlight the potential of the EP/KCN composite as a scalable, cost-effective solution for the removal of CECs from wastewater, driven by renewable solar energy. Keywords: Photocatalysis; Potassium-doping; Graphitic Carbon Nitride; Expanded Perlite; Tire Wear Pollutant; Wastewater Treatment https://doi.org/10.1016/j.seppur.2025.132523

Abstract One of the main challenges in applying photocatalysts for water treatment is the complex separation and recycling process. In this study, we developed highly stable, porous zinc oxide nanorods (ZnO NRs) immobilized on glass vials using a solvent exchange process (SEP) and hydrothermal calcination. Key parameters, including oleic acid concentration and hydrothermal growth time, were optimized to maximize the active surface area, significantly enhancing photodegradation performance. Under the best conditions, ZnO NRs-coated vials achieved nearly 100% degradation of sulfamethoxazole (SMX) in 10 h of simulated solar irradiation. Depositing silver nanoparticles on the surface of ZnO NRs (Ag/ZnO NRs) further improved performance, reducing degradation time to 4 h and increasing photocatalyst stability. The Ag/ZnO NRs-coated vials, optimized with an Ag precursor concentration of 0.05 M, also demonstrated high degradation rates ( 99%) for eight organic micropollutants at environmentally relevant concentrations over multiple reuse cycles and with minimal metal leaching. This study presents an innovative, tunable method for immobilizing photocatalysts on glass substrates, offering high surface area, excellent photocatalytic activity, and mechanical properties, making it highly suitable for water treatment applications. Keywords: Immobilized photocatalyst; ZnO nanorods; Silver deposition; Solar radiation; Organic contaminants https://doi.org/10.1016/j.watres.2024.122736

Abstract Peracetic acid-based advanced oxidation processes (PAA–AOPs), which generate various reactive radicals, have garnered substantial attention for the degradation of emerging contaminants (ECs). However, nonselective radical-based PAA–AOPs often suffer from interference by water matrix components, causing low contaminants removal efficiency. This study explores the use of amino-(NH2)-functionalized metal–organic frameworks (MIL-101(Fe)-NH2) as heterogeneous catalysts for PAA activation, enabling the generation of high-valent iron- (Fe)–oxo species (Fe(IV)) capable of efficiently degrading ECs (80 −100 %, within 30 min). The Fe(II) clusters in MIL-101(Fe)-NH2, modulated by electron-donating −NH2 groups, play a pivotal role in Fe(IV) generation. Scavenger and probe experiments confirmed Fe(IV) as the primary reactive species responsible for ECs degradation. Density functional theory calculations demonstrated that the four-electron transfer to generate Fe(IV) has lower free energy than the two-electron transfer to generate organic radicals (e.g., CH3COO• and CH3C(O)OO•). Furthermore, thermodynamically unfavorable CH3COO• desorption further promotes Fe(IV) generation. The PAA/MIL-101(Fe)-NH2 system efficiently degraded SMX (kapp= 121.2 −287.2 M−1s−1) and other ECs (kapp= 40 −432 M−1s−1) with minimal interference from water matrix components and excellent reusability. This study demonstrates that MIL-101(Fe)-NH2 is a robust catalyst for PAA activation and provides a novel approach for selectively generating Fe(IV) for ECs degradation. Keywords:  MIL-101(Fe)-NH2; Peracetic acid; Heterogeneous catalysis; Amino ligands; High-valent iron Fe(IV) https://doi.org/10.1016/j.jhazmat.2025.138028

Abstract Sludge drying is an important pretreatment step for municipal dewatered sludge (MDS) treatment and disposal, but the time-consuming and high cost of existing processes have hindered the development of MDS treatment and disposal. In this study, a novel sludge drying technology was proposed on the basis of the characteristics and treatment needs of MDS in China. Pig manure (PM) addition and multisource heat assistance together assisted hyperthermophilic bacteria in achieving rapid drying of MDS. Mechanical factors were optimized via orthogonal experiments, and the optimum PM addition ratio was determined. The relationship between energy input (generation) and output in the system was explored to reveal the reasons why the novel drying technology exhibited superiority. Compared with the traditional biological drying technique and the thermal drying technique, the novel technique has the advantages of high efficiency, time savings and low cost. After 24 h of drying, the moisture content, organic matter content and net calorific value on an air-dried basis (Qnet, V,Mad) of the dried products were 31.43 ± 0.91 %, 72.47 ± 1.89 % and 16.94 ± 0.35 MJ/kg, respectively, which met the requirements of heat recovery and utilization for subsequent thermal treatment. The energy input (generation) to the system exceeded the energy output, indicating that the drying process was positively spontaneous. Multisource heat assistance accounted for 81.6 % of the total generated (input) energy, and 86.43 % of the energy was used for moisture evaporation, indicating high energy utilization of the drying system. In addition, cost savings of US $11.46–16.84/ton (¥83-122.10/ton) were achieved when MDS was treated via the novel drying technology. Overall, the novel drying technology proposed in this study provides feasible, efficient and cost-saving pretreatment technology and ideas for MDS treatment and disposal engineering. Keywords : Municipal dewatered sludge; Bio-drying; Multisource heat assistance; Pig manure; Hyperthermophilic bacteria; Evaluation https://doi.org/10.1016/j.wmb.2025.100193

Abstract Elimination of stubborn organic micropollutants from water is crucial for bioaccumulation prevention and ecosystem protection. Cold plasma activation technology is a clean, sustainable, and highly effective approach to the degradation of micropollutants and pathogens in contaminated water. In this study, we focus on understanding the processes of simultaneous degradation of multiple micropollutants (8 types at maximum) in flowing water by the recently developed microbubble-enhanced cold plasma activation (MB-CPA) technology. The degradation of micropollutants with the treatment time was analyzed by using ultrahigh performance liquid chromatography coupled to a triple quadrupole mass spectrometer (UHPLC-QQQ-MS). We found that the degradation efficiencies of all compounds increase rapidly under strong activation conditions that can lead to above 98% removal of a model compound. After long treatment duration or at a fast flow rate, the removal efficiency was sufficiently high for all compounds that were either easy or hard to degrade. The large variation in degradation efficiencies was present under mild activation conditions. The electron spinning resonance measurements reveal a greater abundance of hydroxyl radicals in treated synthetic river water than pure water, highlighting the effects of water matrix on the degradation efficiency. The understanding from this work may help to design the activation process and minimize the energy consumption for the simultaneous elimination of pollutants in diverse and complex water bodies by cold plasma technology. Keywords: Cold plasma; Microbubble; Micropollutant; Water decontamination; Disinfection Qiuyun Lu, Deepak Panchal, Lingling Yang, Ziya Saedi, Mohamed Gamal El-Din, Xuehua Zhang, Simultaneous degradation of multiple micropollutants in flowing water by mild and strong microbubble-enhanced cold plasma activation, Water Research, Volume 280, 2025,123435, ISSN 0043-1354, https://doi.org/10.1016/j.watres.2025.123435 .

Abstract The incipient motion threshold of microplastics (MPs), defined as the condition that is just sufficient to initiate MP movement, is key to assessing the transport and fate of MPs in water bodies, yet only a few studies have focused on its prediction. This study experimentally investigated the effects of bed roughness (smooth and rough beds) and MP properties (shapes, sizes, and densities) on the incipient velocity ( U i) and critical shear stress (τc) of exposed MPs in an open-channel flow. For a total of 19 types of MPs, U i and τc were found to range from 0.06 to 0.21 m/s and 0.01 to 0.075 N/m2, respectively. The commonly used thresholds for sediment transport, for example, critical shield parameter Θc and movability number Λc, were established for MPs based on τc. Based on the experimental data of the literature and this study, it was found that predictions of Θc and Λc for sediments do not apply to MPs. A new explicit formula for Λc was proposed for predicting the incipient motion of MPs by introducing the dimensionless particle diameter ( d *) and a new dimensionless parameter related to the particle size, density, and shape. The new formula has an absolute error of 12.3%, which is smaller than the existing formula for MPs (55.6%). https://doi.org/10.1021/acs.est.2c04415 Zijian Yu, Weiwei Yao, Mark Loewen, Xiaochen Li, and Wenming Zhang Environmental Science & Technology 2022 56 (20), 14498-14506.

Abstract Wet ponds have been extensively used for controlling stormwater pollutants, such as sediment and nutrients, in urban watersheds. The removal of pollutants relies on a combination of physical, chemical, and biological processes. It is crucial to assess the performance of wet ponds in terms of removal efficiency and develop an effective modeling scheme for removal efficiency prediction to optimize water quality management . To achieve this, a two-year field program was conducted at two wet ponds in Calgary, Alberta, Canada to evaluate the wet ponds' performance. Additionally, machine learning (ML) algorithms have been shown to provide promising predictions in datasets with intricate interactions between variables. In this study, the generalized linear model (GLM), partial least squares (PLS) regression, support vector machine (SVM), random forest (RF), and K-nearest neighbors (KNN) were applied to predict the outflow concentrations of three key pollutants: total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP). Generally, the concentrations of inflow pollutants in the two study ponds are highly variable, and a wide range of removal efficiencies are observed. The results indicate that the concentrations of TSS, TN, and TP decrease significantly from the inlet to outlet of the ponds. Meanwhile, inflow concentration, rainfall characteristics, and wind are important indicators of pond removal efficiency. In addition, ML algorithms can be an effective approach for predicting outflow water quality: PLS, GLM, and SVM have shown strong potential to capture the dynamic interactions in wet ponds and predict the outflow concentration. This study highlights the complexity of pollutant removal dynamics in wet ponds and demonstrates the potential of data-driven outflow water quality prediction. https://doi.org/10.1016/j.scitotenv.2023.167119 Yang Yang, David Z. Zhu, Mark R. Loewen, Sherif S. Ahmed, Wenming Zhang, Haibin Yan, Bert van Duin, Khizar Mahmood, Evaluation of pollutant removal efficiency of urban stormwater wet ponds and the application of machine learning algorithms, Science of The Total Environment, Volume 905, 2023, 167119, ISSN 0048-9697.