Inland rivers play a crucial role in regulating the methane (CH4) budget via microbial carbon cycling. CH4 emissions vary significantly among rivers with different land covers, yet the regulatory mechanisms of CH4-cycling microorganisms across different land covers remain less understood. This study intergrates in-situ CH4 measurements with amplicon and metagenomic sequencing to investigate CH4-cycling microbial community composition and metabolic functions in regulating CH4 emissions across rivers with different land covers. Our results show that agricultural and urban rivers significantly increase riverine CH4 emission fluxes by 14 and 34 times than forest rivers, respectively. Urban and agricultural river sediments exhibited higher methanogenic abundance, but lower methanotrophic abundance than forest river sediments. Acetoclastic methanogens dominate the methanogenic communities of agricultural rivers, enhanced by high NO3− and DOC concentrations. Furthermore, methanogenic metagenome-assembled genomes (MAGs) recovered from agricultural rivers, which affiliated to Methanosarcina, carried the complete set of genes encoding for the enzymes in acetoclastic methanogenesis. In contrast, hydrogenotrophic methanogens drive CH4 production in urban rivers, favored by low DOC: NH4+ ratios that enable methanogenesis independent of organic carbon. Lower CH4 emissions in agricultural rivers compared to urban rivers might be partly due to the greater sulfate-dependent anaerobic methane-oxidation. In forest rivers, type I methanotrophs outcompetes methanogens, aided by suitable sediment pH and larger sediment particle sizes, fostering oxic conditions that suppress CH4 emissions. This study reveals versatile microbial mechanisms underlying riverine CH4 emissions across land covers, enhancing understanding of microbial-mediated riverine CH4 cycling.
{"title":"Microbial regulatory mechanisms underlying methane emission in rivers with different land covers","authors":"Yuan Xin , Qun Gao , Sibo Zhang , Zhuangzhuang Zhang , Junfeng Wang , Xinghui Xia","doi":"10.1016/j.watres.2025.123680","DOIUrl":"10.1016/j.watres.2025.123680","url":null,"abstract":"<div><div>Inland rivers play a crucial role in regulating the methane (CH<sub>4</sub>) budget via microbial carbon cycling. CH<sub>4</sub> emissions vary significantly among rivers with different land covers, yet the regulatory mechanisms of CH<sub>4</sub>-cycling microorganisms across different land covers remain less understood. This study intergrates in-situ CH<sub>4</sub> measurements with amplicon and metagenomic sequencing to investigate CH<sub>4</sub>-cycling microbial community composition and metabolic functions in regulating CH<sub>4</sub> emissions across rivers with different land covers. Our results show that agricultural and urban rivers significantly increase riverine CH<sub>4</sub> emission fluxes by 14 and 34 times than forest rivers, respectively. Urban and agricultural river sediments exhibited higher methanogenic abundance, but lower methanotrophic abundance than forest river sediments. Acetoclastic methanogens dominate the methanogenic communities of agricultural rivers, enhanced by high NO<sub>3</sub><sup>−</sup> and DOC concentrations. Furthermore, methanogenic metagenome-assembled genomes (MAGs) recovered from agricultural rivers, which affiliated to <em>Methanosarcina</em>, carried the complete set of genes encoding for the enzymes in acetoclastic methanogenesis. In contrast, hydrogenotrophic methanogens drive CH<sub>4</sub> production in urban rivers, favored by low DOC: NH<sub>4</sub><sup>+</sup> ratios that enable methanogenesis independent of organic carbon. Lower CH<sub>4</sub> emissions in agricultural rivers compared to urban rivers might be partly due to the greater sulfate-dependent anaerobic methane-oxidation. In forest rivers, type I methanotrophs outcompetes methanogens, aided by suitable sediment pH and larger sediment particle sizes, fostering oxic conditions that suppress CH<sub>4</sub> emissions. This study reveals versatile microbial mechanisms underlying riverine CH<sub>4</sub> emissions across land covers, enhancing understanding of microbial-mediated riverine CH<sub>4</sub> cycling.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"281 ","pages":"Article 123680"},"PeriodicalIF":11.4,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143849882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-19DOI: 10.1016/j.watres.2025.123682
Xinhui Liu , Yu Yang , Nigel J D Graham , Satoshi Takizawa , How Yong Ng
Nanofiltration (NF) is an effective process for micro-/nano-plastics (MNPs) interception, but the impact of accumulated MNPs on the microbial community structure and metabolic pathways of biofilms on NF membranes remains unclear. This provides uncertainty with respect to membrane biofouling behavior and the risks to efficient NF operations. In this study, the size-dependent (20 nm–25 μm) and concentration-dependent (0.1–50 mg·L−1) effects of MNPs on the biofouling of a NF membrane treating secondary wastewater effluent were studied. Three MNPs-tolerant, hypermetabolic and polystyrene-degradable genera (i.e., Acinetobacter, Novosphingobium and Asticcacaulis) were detected in biofilms as dominant taxonomic compositions. MNPs led to an increase of 19.3 %–76.7 % in biomass contents and a more rapid decrease in permeate flux, with 0.1 mg·L−1 of 80 nm NPs causing the most severe membrane biofouling. Metagenomic analysis revealed that MNPs upregulated enzymes involved in exopolysaccharide (ExoA/L/M/P/Q/X/Y/Z) and tyrosine (COMT, FeaB and AOC3) biosynthesis and quorum sensing (PhzF and CiaH/R), and suppressed cell motility pathways including flagellar assembly and bacterial chemotaxis. Novel types of perforated column spacer (PCS) enhanced the hydrodynamics of the membrane feed with a lower pressure drop and higher fluid velocity, introduced micro-jets and greater mass transfer inside feed channels, thus eliminating the deposition of MNPs and mitigating membrane biofouling. Overall, a greater understanding of the interaction mechanisms between MNPs and membrane biofouling in secondary effluent filtration will help develop more effective MNPs management strategies and achieve more sustainable NF operations.
{"title":"Deciphering membrane biofouling induced by micro-/nano-plastics in nanofiltration: Metagenomic insights and spacer-driven mitigations","authors":"Xinhui Liu , Yu Yang , Nigel J D Graham , Satoshi Takizawa , How Yong Ng","doi":"10.1016/j.watres.2025.123682","DOIUrl":"10.1016/j.watres.2025.123682","url":null,"abstract":"<div><div>Nanofiltration (NF) is an effective process for micro-/nano-plastics (MNPs) interception, but the impact of accumulated MNPs on the microbial community structure and metabolic pathways of biofilms on NF membranes remains unclear. This provides uncertainty with respect to membrane biofouling behavior and the risks to efficient NF operations. In this study, the size-dependent (20 nm–25 μm) and concentration-dependent (0.1–50 mg·<em>L</em><sup>−1</sup>) effects of MNPs on the biofouling of a NF membrane treating secondary wastewater effluent were studied. Three MNPs-tolerant, hypermetabolic and polystyrene-degradable genera (<em>i.e., Acinetobacter, Novosphingobium</em> and <em>Asticcacaulis</em>) were detected in biofilms as dominant taxonomic compositions. MNPs led to an increase of 19.3 %–76.7 % in biomass contents and a more rapid decrease in permeate flux, with 0.1 mg·<em>L</em><sup>−1</sup> of 80 nm NPs causing the most severe membrane biofouling. Metagenomic analysis revealed that MNPs upregulated enzymes involved in exopolysaccharide (ExoA/L/M/P/Q/X/Y/Z) and tyrosine (COMT, FeaB and AOC3) biosynthesis and quorum sensing (PhzF and CiaH/R), and suppressed cell motility pathways including flagellar assembly and bacterial chemotaxis. Novel types of perforated column spacer (PCS) enhanced the hydrodynamics of the membrane feed with a lower pressure drop and higher fluid velocity, introduced micro-jets and greater mass transfer inside feed channels, thus eliminating the deposition of MNPs and mitigating membrane biofouling. Overall, a greater understanding of the interaction mechanisms between MNPs and membrane biofouling in secondary effluent filtration will help develop more effective MNPs management strategies and achieve more sustainable NF operations.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"281 ","pages":"Article 123682"},"PeriodicalIF":11.4,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143849881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Selective ion separation from acid mine drainage (AMD) under extreme acidic conditions presents a critical environmental challenge. While membrane-based technologies show promise for advancing water treatment processes, implementation in AMD treatment requires membranes that combine exceptional acid stability with precise ion sieving capabilities. Inspired by the ion retention characteristics of natural clay minerals, we have developed cation-selective membranes using vermiculite nanosheets as building blocks. The vermiculite membranes (VM) featured high acid stability and well-ordered two-dimensional nanochannels (2 Å), achieving a high H+ permeation rate of 3.24 mol m−2 h−1. The VM demonstrated exceptional selectivity between monovalent and metals ions, with a H+/Fe3+ selectivity factor of 1284 in single-cation transport process. In complex multi-ion environments, the VM maintained stable separation performance, achieving a H+/Fe3+ selectivity of 1000 in mixed solutions containing H+, K+, Na+, Ca2+, Mg2+ and Fe3+. Additionally, VM effectively blocked other common AMD metals, including Cu2+, Co2+, Ni2+ and Mn2+, while maintaining stable separation performance even at extreme low pH values (pH = 1). Through integrated theoretical calculations and experiments, we revealed that the synergistic effects of ultra-confined nanochannels (4∼5 Å) and surface charge created enhanced energy barriers for trivalent ion transport, resulting in high ion selectivity. Beyond providing an effective solution for AMD remediation, this work establishes vermiculite-based membranes as promising candidates for ion separation applications.
{"title":"Selective acid recovery and metal separation from acid mine drainage using a highly stable vermiculite membrane","authors":"Lina Zhang, Chongwen Shi, Qianli Xie, Zhen Qi, Fangzhou Li, Guanghe Li, Fang Zhang","doi":"10.1016/j.watres.2025.123676","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123676","url":null,"abstract":"Selective ion separation from acid mine drainage (AMD) under extreme acidic conditions presents a critical environmental challenge. While membrane-based technologies show promise for advancing water treatment processes, implementation in AMD treatment requires membranes that combine exceptional acid stability with precise ion sieving capabilities. Inspired by the ion retention characteristics of natural clay minerals, we have developed cation-selective membranes using vermiculite nanosheets as building blocks. The vermiculite membranes (VM) featured high acid stability and well-ordered two-dimensional nanochannels (2 Å), achieving a high H<sup>+</sup> permeation rate of 3.24 mol m<sup>−2</sup> h<sup>−1</sup>. The VM demonstrated exceptional selectivity between monovalent and metals ions, with a H<sup>+</sup>/Fe<sup>3+</sup> selectivity factor of 1284 in single-cation transport process. In complex multi-ion environments, the VM maintained stable separation performance, achieving a H<sup>+</sup>/Fe<sup>3+</sup> selectivity of 1000 in mixed solutions containing H<sup>+</sup>, K<sup>+</sup>, Na<sup>+</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup> and Fe<sup>3+</sup>. Additionally, VM effectively blocked other common AMD metals, including Cu<sup>2+</sup>, Co<sup>2+</sup>, Ni<sup>2+</sup> and Mn<sup>2+</sup>, while maintaining stable separation performance even at extreme low pH values (pH = 1). Through integrated theoretical calculations and experiments, we revealed that the synergistic effects of ultra-confined nanochannels (4∼5 Å) and surface charge created enhanced energy barriers for trivalent ion transport, resulting in high ion selectivity. Beyond providing an effective solution for AMD remediation, this work establishes vermiculite-based membranes as promising candidates for ion separation applications.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"61 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143849884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-18DOI: 10.1016/j.watres.2025.123608
Jiaxun Jiang , Dongmei Han , Yi Xiao , Xianfang Song
{"title":"Corrigendum to “Occurrence, migration, and assessment of human health and ecological risks of PFASs and EDCs in groundwater of Northeast China” [Water Research 269 (2025) 122810]","authors":"Jiaxun Jiang , Dongmei Han , Yi Xiao , Xianfang Song","doi":"10.1016/j.watres.2025.123608","DOIUrl":"10.1016/j.watres.2025.123608","url":null,"abstract":"","PeriodicalId":443,"journal":{"name":"Water Research","volume":"282 ","pages":"Article 123608"},"PeriodicalIF":11.4,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Microbial electrolysis cell-anaerobic digestion (MEC-AD) is a cost-effective approach for methane (CH₄) recovery from food waste, but its CH₄ conversion efficiency requires improvement. To address this, a MIL-100(Fe)-modified carbon cloth anode was developed to enhance anodic biofilm formation and CH₄ bioconversion efficiency. At an applied voltage of 0.8 V, the highest daily CH₄ yield reached 141.6 mL/g COD/d, a 61% increase, and increased further to 227.5 mL/g COD/d under intermittent power supply. By facilitating extracellular electron transfer (EET) in electrogenic bacteria, MIL-100(Fe) regulated biofilm thickness and maintained dynamic biofilm equilibrium. Additionally, as an external capacitor, MIL-100(Fe) functioned as a “temporary storage site” for electrons under intermittent power supply, reducing bioelectron loss. Metagenomic analysis revealed that MIL-100(Fe) significantly enriched Bacteroidia and Methanosarcina, promoting carbohydrate metabolism and CH₄ production. Under intermittent power supply, MIL-100(Fe) further enriched Geobacter, enhancing electron transfer efficiency. This study demonstrates that iron-based anode modification effectively enhances CH₄ production from food waste by optimizing biofilm structure and metabolic pathways, providing a promising strategy for improving MEC-AD performance.
{"title":"Iron-based materials maintaining dynamic equilibrium of the biofilm and function as external capacitors to minimize electron loss in intermittent power supply during MEC-AD methane production","authors":"Changqing Liu, Shenghan Yan, Xingguang Luo, Yuyi Zheng, Guangyin Zhen","doi":"10.1016/j.watres.2025.123677","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123677","url":null,"abstract":"Microbial electrolysis cell-anaerobic digestion (MEC-AD) is a cost-effective approach for methane (CH₄) recovery from food waste, but its CH₄ conversion efficiency requires improvement. To address this, a MIL-100(Fe)-modified carbon cloth anode was developed to enhance anodic biofilm formation and CH₄ bioconversion efficiency. At an applied voltage of 0.8 V, the highest daily CH₄ yield reached 141.6 mL/g COD/d, a 61% increase, and increased further to 227.5 mL/g COD/d under intermittent power supply. By facilitating extracellular electron transfer (EET) in electrogenic bacteria, MIL-100(Fe) regulated biofilm thickness and maintained dynamic biofilm equilibrium. Additionally, as an external capacitor, MIL-100(Fe) functioned as a “temporary storage site” for electrons under intermittent power supply, reducing bioelectron loss. Metagenomic analysis revealed that MIL-100(Fe) significantly enriched <em>Bacteroidia</em> and <em>Methanosarcina</em>, promoting carbohydrate metabolism and CH₄ production. Under intermittent power supply, MIL-100(Fe) further enriched <em>Geobacter</em>, enhancing electron transfer efficiency. This study demonstrates that iron-based anode modification effectively enhances CH₄ production from food waste by optimizing biofilm structure and metabolic pathways, providing a promising strategy for improving MEC-AD performance.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"108 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143849885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-17DOI: 10.1016/j.watres.2025.123665
Yuxin Zhu , Qingxia Miao , Heng Lyu , Yiling Zheng , Wenyu Liu , Yunmei Li , Junda Li , Fangfang Chen , Song Miao
Phytoplankton communities play a crucial role in the lake ecosystem due to their varying characteristics, functions, and impacts of different phytoplankton groups. Understanding the composition of phytoplankton groups in freshwater lakes is essential for comprehending geochemical processes and managing water quality. In this study, an improved Diagnostic Pigment Analysis method for freshwater lakes was developed and the proportion of five major phytoplankton groups—Dinophyta, Cryptophyta, Chlorophyta, Cyanophyta, and Bacillariophyta—was derived through the absorption-decomposition method. The validation results demonstrated that the developed algorithm had satisfactory estimation accuracy for all five groups. Among all the phytoplankton groups, Cyanophyta achieved the best performance, with Median Absolute Percentage Error (MAPE) of 14.22 %, and Bias of 8.37 %. In contrast, Cryptophyta exhibited the poorest accuracy, with MAPE as high as 40.24 %. The MAPE values ranged from 10.91 % to 33.65 %, and the Bias values ranged from 1.06 % to 9.38 %. Meanwhile, the developed algorithm was successfully applied to the Ocean and Land Color Instrument (OLCI) images for mapping the spatial distribution of phytoplankton communities in Lake Taihu, demonstrating its ability to be applied to satellite imagery. This proposed algorithm provided a new approach to quantitatively determine the composition of phytoplankton communities in freshwater lakes, which can obtain valuable insights from observing the composition and succession patterns of these communities from satellite platforms.
{"title":"An approach for mapping phytoplankton communities in freshwater lakes based on phytoplankton absorption features","authors":"Yuxin Zhu , Qingxia Miao , Heng Lyu , Yiling Zheng , Wenyu Liu , Yunmei Li , Junda Li , Fangfang Chen , Song Miao","doi":"10.1016/j.watres.2025.123665","DOIUrl":"10.1016/j.watres.2025.123665","url":null,"abstract":"<div><div>Phytoplankton communities play a crucial role in the lake ecosystem due to their varying characteristics, functions, and impacts of different phytoplankton groups. Understanding the composition of phytoplankton groups in freshwater lakes is essential for comprehending geochemical processes and managing water quality. In this study, an improved Diagnostic Pigment Analysis method for freshwater lakes was developed and the proportion of five major phytoplankton groups—Dinophyta, Cryptophyta, Chlorophyta, Cyanophyta, and Bacillariophyta—was derived through the absorption-decomposition method. The validation results demonstrated that the developed algorithm had satisfactory estimation accuracy for all five groups. Among all the phytoplankton groups, Cyanophyta achieved the best performance, with Median Absolute Percentage Error (MAPE) of 14.22 %, and Bias of 8.37 %. In contrast, Cryptophyta exhibited the poorest accuracy, with MAPE as high as 40.24 %. The MAPE values ranged from 10.91 % to 33.65 %, and the Bias values ranged from 1.06 % to 9.38 %. Meanwhile, the developed algorithm was successfully applied to the Ocean and Land Color Instrument (OLCI) images for mapping the spatial distribution of phytoplankton communities in Lake Taihu, demonstrating its ability to be applied to satellite imagery. This proposed algorithm provided a new approach to quantitatively determine the composition of phytoplankton communities in freshwater lakes, which can obtain valuable insights from observing the composition and succession patterns of these communities from satellite platforms.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"282 ","pages":"Article 123665"},"PeriodicalIF":11.4,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-17DOI: 10.1016/j.watres.2025.123660
Hao-yu Guo, Xiao-mao Wang, Kunpeng Wang, Shuming Liu
Loose nanofiltration (LNF) membranes hold great promise for the selective rejection of natural organic matter (NOM) while maintaining mineral salts to produce high-quality drinking water. Nevertheless, the rejection selectivity performance is not only determined by the inherent properties of membranes but also influenced by the feed water compositions. This study explored the inevitable adsorption of NOM and inorganic ions onto and inside membrane materials, which in turn altered the charge properties of LNF membranes, thereby affecting the rejection selectivity. Zeta potential measurements, X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry technique were employed to characterize solute adsorption on the membrane surface and within the membrane pores. Filtration experiments using synthetic and natural waters were conducted to assess the contribution of electrostatic effects and evaluate the membrane rejection performance. Results revealed that LNF membrane surfaces during filtration were readily coated by NOM molecules, probably via hydrophobic interactions, which in turn adsorbed divalent cations that actually determined the net charge density on the membrane surface. Additionally, NOM adsorption within the membrane pores largely altered pore charge properties, particularly of the sulfonated polyethersulfone membranes (e.g. NTR7450), where deprotonated sulfonic groups otherwise contributed to a high charge density. These interactions among NOM, divalent cations and membrane materials greatly reduced charge density on the membrane surface and largely diminished charges in pores, leading to decreased rejection of both NOM and mineral salts, as well as the mitigation of co-ion competition effects. Nevertheless, the UA60 membrane, having a molecular weight cut-off of ∼1000 Da, rejected NOM by ∼70 % while maintaining ∼95 % bicarbonate and ∼65 % hardness ions in the treated water, demonstrating fairly good selectivity. These findings offer valuable insights for optimizing LNF membranes to improve the safety, chemical stability and palatability of treated drinking water.
{"title":"Adsorption of natural organic matter and divalent cations onto / inside loose nanofiltration membranes: Implications for drinking water treatment from rejection selectivity perspective","authors":"Hao-yu Guo, Xiao-mao Wang, Kunpeng Wang, Shuming Liu","doi":"10.1016/j.watres.2025.123660","DOIUrl":"10.1016/j.watres.2025.123660","url":null,"abstract":"<div><div>Loose nanofiltration (LNF) membranes hold great promise for the selective rejection of natural organic matter (NOM) while maintaining mineral salts to produce high-quality drinking water. Nevertheless, the rejection selectivity performance is not only determined by the inherent properties of membranes but also influenced by the feed water compositions. This study explored the inevitable adsorption of NOM and inorganic ions onto and inside membrane materials, which in turn altered the charge properties of LNF membranes, thereby affecting the rejection selectivity. Zeta potential measurements, X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry technique were employed to characterize solute adsorption on the membrane surface and within the membrane pores. Filtration experiments using synthetic and natural waters were conducted to assess the contribution of electrostatic effects and evaluate the membrane rejection performance. Results revealed that LNF membrane surfaces during filtration were readily coated by NOM molecules, probably via hydrophobic interactions, which in turn adsorbed divalent cations that actually determined the net charge density on the membrane surface. Additionally, NOM adsorption within the membrane pores largely altered pore charge properties, particularly of the sulfonated polyethersulfone membranes (e.g. NTR7450), where deprotonated sulfonic groups otherwise contributed to a high charge density. These interactions among NOM, divalent cations and membrane materials greatly reduced charge density on the membrane surface and largely diminished charges in pores, leading to decreased rejection of both NOM and mineral salts, as well as the mitigation of co-ion competition effects. Nevertheless, the UA60 membrane, having a molecular weight cut-off of ∼1000 Da, rejected NOM by ∼70 % while maintaining ∼95 % bicarbonate and ∼65 % hardness ions in the treated water, demonstrating fairly good selectivity. These findings offer valuable insights for optimizing LNF membranes to improve the safety, chemical stability and palatability of treated drinking water.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"282 ","pages":"Article 123660"},"PeriodicalIF":11.4,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-17DOI: 10.1016/j.watres.2025.123672
Libing Liu , Sen Lu , Zhiyuan Jin , Jiangwei Lou , Weijun Zhang , Dongsheng Wang
Al13 ([AlO4Al12(OH)24(H2O)12]7+) is widely recognized as one of the advantageous species of Al-based coagulants, and its transformation process and micro-interface interaction with pollutants in water treatment continue to attract the attention of researchers. Based on relevant literatures in the past decades, this review summarizes and discusses the characterization methods, stability and aggregation, coagulation performance and mechanism of Al13. The technique development and method establishment such as 27Al nuclear magnetic resonance, electrospray ionization mass spectrometry, and Al-Ferron complexation timed spectrophotometry provide technical support for qualitative and quantitative detection of the species transformation of Al13. Al13 pre-formed by forced hydrolysis is of high structural stability, and solution pH, high Al concentration, and high temperature are important factors affecting its further hydrolysis, aggregation, dissociation or polymerization. Under circumneutral pH conditions in practical water treatment processes, unlike traditional Al salts which undergo extensive hydrolysis to generate Al(OH)3, Al13 transforms into Al13 aggregates. This is the key for Al13 to exert its superior coagulation performance and makes it shows significantly higher efficiency than traditional Al salts in removing particulate matter and organic substances. Specifically, Al13 shows a broader effective dosage range and pH range compared with AlCl3 through the coagulation mechanisms such as electrostatic patch, in-situ aggregation bridging, and complexation adsorption. Furthermore, the flocs formed by Al13 coagulation exhibit a more compact crystalline structure and higher strength, which helps reduce residual Al concentrations. A comprehensive investigation into the hydrolysis characteristics of Al13 and its role in coagulation is crucial for optimizing coagulation processes, while also providing a theoretical foundation for developing novel high-efficiency composite coagulants.
{"title":"Hydrolysis of Al13 and its coagulation mechanism: Role of speciation stability and transformation","authors":"Libing Liu , Sen Lu , Zhiyuan Jin , Jiangwei Lou , Weijun Zhang , Dongsheng Wang","doi":"10.1016/j.watres.2025.123672","DOIUrl":"10.1016/j.watres.2025.123672","url":null,"abstract":"<div><div>Al<sub>13</sub> ([AlO<sub>4</sub>Al<sub>12</sub>(OH)<sub>24</sub>(H<sub>2</sub>O)<sub>12</sub>]<sup>7+</sup>) is widely recognized as one of the advantageous species of Al-based coagulants, and its transformation process and micro-interface interaction with pollutants in water treatment continue to attract the attention of researchers. Based on relevant literatures in the past decades, this review summarizes and discusses the characterization methods, stability and aggregation, coagulation performance and mechanism of Al<sub>13</sub>. The technique development and method establishment such as <sup>27</sup>Al nuclear magnetic resonance, electrospray ionization mass spectrometry, and Al-Ferron complexation timed spectrophotometry provide technical support for qualitative and quantitative detection of the species transformation of Al<sub>13</sub>. Al<sub>13</sub> pre-formed by forced hydrolysis is of high structural stability, and solution pH, high Al concentration, and high temperature are important factors affecting its further hydrolysis, aggregation, dissociation or polymerization. Under circumneutral pH conditions in practical water treatment processes, unlike traditional Al salts which undergo extensive hydrolysis to generate Al(OH)<sub>3</sub>, Al<sub>13</sub> transforms into Al<sub>13</sub> aggregates. This is the key for Al<sub>13</sub> to exert its superior coagulation performance and makes it shows significantly higher efficiency than traditional Al salts in removing particulate matter and organic substances. Specifically, Al<sub>13</sub> shows a broader effective dosage range and pH range compared with AlCl<sub>3</sub> through the coagulation mechanisms such as electrostatic patch, in-situ aggregation bridging, and complexation adsorption. Furthermore, the flocs formed by Al<sub>13</sub> coagulation exhibit a more compact crystalline structure and higher strength, which helps reduce residual Al concentrations. A comprehensive investigation into the hydrolysis characteristics of Al<sub>13</sub> and its role in coagulation is crucial for optimizing coagulation processes, while also providing a theoretical foundation for developing novel high-efficiency composite coagulants.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"281 ","pages":"Article 123672"},"PeriodicalIF":11.4,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The zebrafish embryo is a valuable model for evaluating whole effluent toxicity (WET). However, the widely recognized acute toxicity indicator, based on International Organization of Standardization (ISO) methods, requires large numbers of embryos and is often time-consuming due to its complex experimental procedures. In this study, we propose an alternative to the conventional reliance on ISO standards by developing a model-driven high-throughput assay that utilizes actual wastewater, enabling rapid LC10 (the lethal concentration at which 10 % of the test organisms are affected) prediction through machine learning techniques and multidimensional indicators derived from streamlined experimental procedures. We compared three streamlined toxicity assays—developmental toxicity, behavioral toxicity, and vascular toxicity—along with five different models. Among these, the Lasso model based on behavioral toxicity emerged as the most effective, achieving an R2 value of 0.893 while reducing experimental time by 5- to 8-fold. Furthermore, fivefold cross-validation confirmed its robust predictive accuracy. The application of this model-driven high-throughput assay across 100 wastewater treatment plants in China highlights the crucial role of biological treatment, particularly aerobic processes and secondary sedimentation, in reducing toxicity, thereby providing valuable insights into their functions. This high-throughput assay not only surpasses the ISO standard method in efficiency but also substantially decreases embryo usage, facilitating rapid WET assessments of actual wastewater with larger sample sizes.
{"title":"Model-driven high-throughput zebrafish embryo assay for evaluating whole effluent toxicity variation across 100 full-scale wastewater treatment plants","authors":"Aixia Zhao, Hongwei Bai, Xingchen Bao, Kewei Liao, Hongqiang Ren, Haidong Hu","doi":"10.1016/j.watres.2025.123675","DOIUrl":"10.1016/j.watres.2025.123675","url":null,"abstract":"<div><div>The zebrafish embryo is a valuable model for evaluating whole effluent toxicity (WET). However, the widely recognized acute toxicity indicator, based on International Organization of Standardization (ISO) methods, requires large numbers of embryos and is often time-consuming due to its complex experimental procedures. In this study, we propose an alternative to the conventional reliance on ISO standards by developing a model-driven high-throughput assay that utilizes actual wastewater, enabling rapid LC<sub>10</sub> (the lethal concentration at which 10 % of the test organisms are affected) prediction through machine learning techniques and multidimensional indicators derived from streamlined experimental procedures. We compared three streamlined toxicity assays—developmental toxicity, behavioral toxicity, and vascular toxicity—along with five different models. Among these, the Lasso model based on behavioral toxicity emerged as the most effective, achieving an R<sup>2</sup> value of 0.893 while reducing experimental time by 5- to 8-fold. Furthermore, fivefold cross-validation confirmed its robust predictive accuracy. The application of this model-driven high-throughput assay across 100 wastewater treatment plants in China highlights the crucial role of biological treatment, particularly aerobic processes and secondary sedimentation, in reducing toxicity, thereby providing valuable insights into their functions. This high-throughput assay not only surpasses the ISO standard method in efficiency but also substantially decreases embryo usage, facilitating rapid WET assessments of actual wastewater with larger sample sizes.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"281 ","pages":"Article 123675"},"PeriodicalIF":11.4,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-17DOI: 10.1016/j.watres.2025.123671
Vonihanitrinaina D.Z. Andriamanantena R, Yerang Yang, Yves Mong, Hojeong Kang
Headwater streams play a crucial role as significant contributors of greenhouse gases, yet CO2 (carbon dioxide) and CH4 (methane) fluxes from tropical African streams are under-represented, resulting in uncertainties in global estimations. We conducted a three-month sampling of 25 sites in the Ikopa River, Madagascar, where we quantified fluxes and assessed their regulating physicochemical, and biological drivers. Ikopa's headwater streams were a net source of greenhouse gas, with soluble CO2 at 2,483 µatm and dissolved CH4 concentration at 1.44 µmol L-1. Low-order steams released a total of 2.58 Gg CO2 yr-1 and 0.19 Gg CH4 yr-1. Notably, the average CH4 ebullition was 55.66 mmol m−2 d−1, approximately 30 times higher than the global average, and streams draining through grassland areas exhibited higher CH4 emissions. Dissolved oxygen and sediment texture emerged as the primary predictors for CH4 ebullition rates, while partial pressure of CO2 (pCO2) and dissolved CH4 directly impact CO2 and CH4 fluxes. Water temperature, pH level, and mcrA gene abundance directly influenced dissolved CH4 concentration, while soil organic carbon (SOC) content, water temperature, and mcrA gene abundance indirectly impacted CH4 fluxes. The results highlight the overlooked role of grasslands in influencing CH4 emissions in the African tropical river. This study confirms the major role of tropical headwater streams in CH4 emissions and provides new insight into The link between land cover and greenhouse gas emissions.
{"title":"Linking CO2 and CH4 Emissions to the Microbial Community and Land Cover in Tropical Headwater Streams of Madagascar","authors":"Vonihanitrinaina D.Z. Andriamanantena R, Yerang Yang, Yves Mong, Hojeong Kang","doi":"10.1016/j.watres.2025.123671","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123671","url":null,"abstract":"Headwater streams play a crucial role as significant contributors of greenhouse gases, yet CO<sub>2</sub> (carbon dioxide) and CH<sub>4</sub> (methane) fluxes from tropical African streams are under-represented, resulting in uncertainties in global estimations. We conducted a three-month sampling of 25 sites in the Ikopa River, Madagascar, where we quantified fluxes and assessed their regulating physicochemical, and biological drivers. Ikopa's headwater streams were a net source of greenhouse gas, with soluble CO<sub>2</sub> at 2,483 µatm and dissolved CH<sub>4</sub> concentration at 1.44 µmol L<sup>-1</sup>. Low-order steams released a total of 2.58 Gg CO<sub>2</sub> yr<sup>-1</sup> and 0.19 Gg CH<sub>4</sub> yr<sup>-1</sup>. Notably, the average CH<sub>4</sub> ebullition was 55.66 mmol m<sup>−2</sup> d<sup>−1</sup>, approximately 30 times higher than the global average, and streams draining through grassland areas exhibited higher CH<sub>4</sub> emissions. Dissolved oxygen and sediment texture emerged as the primary predictors for CH<sub>4</sub> ebullition rates, while partial pressure of CO<sub>2</sub> (pCO<sub>2</sub>) and dissolved CH<sub>4</sub> directly impact CO<sub>2</sub> and CH<sub>4</sub> fluxes. Water temperature, pH level, and <em>mcrA</em> gene abundance directly influenced dissolved CH<sub>4</sub> concentration, while soil organic carbon (SOC) content, water temperature, and <em>mcrA</em> gene abundance indirectly impacted CH<sub>4</sub> fluxes. The results highlight the overlooked role of grasslands in influencing CH<sub>4</sub> emissions in the African tropical river. This study confirms the major role of tropical headwater streams in CH<sub>4</sub> emissions and provides new insight into The link between land cover and greenhouse gas emissions.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"123 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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