Pub Date : 2025-04-13DOI: 10.1016/j.watres.2025.123647
Sergěj Y.M.H. Seepma, Janou A. Koskamp, Michel G. Colin, Eleftheria Chiou, Rubayat Sobhan, Tim F.J. Bögels, Tom Bastiaan, Hadi Zamanian, Eric T. Baars, Peter J. De Moel, Mariëtte Wolthers, Onno J.I. Kramer
Drinking water softening is an essential treatment step that provides multiple benefits, including public health, reduction of environmental impact, decrease in clogging potential and improvement in heating efficiency. With approximately 35 billion cubic meter of water being softened annually worldwide, the predominant methods are conventional lime/soda-ash softening, nanofiltration, ion exchange, and seeded crystallization through pellet-water softening. This study addresses the limitations in existing predictive models for calcium carbonate (CaCO3) precipitation kinetics in industrial-scale pellet-water softening by experimentally investigating the integral and multivariate effects of particle-, fluid-, water matrix- and reactor properties, on CaCO₃ precipitation kinetics. Fluid characterization experiments were conducted at lab-scale continuous-stirred tank reactors (CSTR), pilot-scale plug-flow reactors (PFR), and full-scale fluidized bed reactors (FBR) at the Waternet Weesperkarspel treatment plant in Amsterdam, The Netherlands, while solid characterization was performed with image analysis software and SEM on pellets and water samples collected during FBR experiments. The calcium removal data obtained from experiments were compared with modeled CaCO3 precipitation rates using and extending the most recently developed water softening model for pellet-water softening. The results predominantly highlight the critical role of mixing dynamics — between softening chemicals, hard influent water and seeding material — for accurate CaCO3 precipitation predictions across various reactor types and other reactor-specific properties such as the residence time of influent hard water. Additional enhancements can be achieved by targeting fluid properties, followed by water matrix properties, and finally particle properties, though these factors exhibit a progressively smaller impact on overall water softening improvement. By implementing these prioritized optimization strategies, the operational control strategy for calcium removal will be enhanced, leading to improvements in cost-effectiveness, sustainability, and reliability in drinking water treatment processes.
{"title":"Operational Control Strategy on Optimal Calcium Removal in Drinking Water Treatment Processes: Insights from Reactor Experiments, Modelling and Particle Characterization","authors":"Sergěj Y.M.H. Seepma, Janou A. Koskamp, Michel G. Colin, Eleftheria Chiou, Rubayat Sobhan, Tim F.J. Bögels, Tom Bastiaan, Hadi Zamanian, Eric T. Baars, Peter J. De Moel, Mariëtte Wolthers, Onno J.I. Kramer","doi":"10.1016/j.watres.2025.123647","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123647","url":null,"abstract":"Drinking water softening is an essential treatment step that provides multiple benefits, including public health, reduction of environmental impact, decrease in clogging potential and improvement in heating efficiency. With approximately 35 billion cubic meter of water being softened annually worldwide, the predominant methods are conventional lime/soda-ash softening, nanofiltration, ion exchange, and seeded crystallization through pellet-water softening. This study addresses the limitations in existing predictive models for calcium carbonate (CaCO<sub>3</sub>) precipitation kinetics in industrial-scale pellet-water softening by experimentally investigating the integral and multivariate effects of particle-, fluid-, water matrix- and reactor properties, on CaCO₃ precipitation kinetics. Fluid characterization experiments were conducted at lab-scale continuous-stirred tank reactors (CSTR), pilot-scale plug-flow reactors (PFR), and full-scale fluidized bed reactors (FBR) at the Waternet Weesperkarspel treatment plant in Amsterdam, The Netherlands, while solid characterization was performed with image analysis software and SEM on pellets and water samples collected during FBR experiments. The calcium removal data obtained from experiments were compared with modeled CaCO<sub>3</sub> precipitation rates using and extending the most recently developed water softening model for pellet-water softening. The results predominantly highlight the critical role of mixing dynamics — between softening chemicals, hard influent water and seeding material — for accurate CaCO<sub>3</sub> precipitation predictions across various reactor types and other reactor-specific properties such as the residence time of influent hard water. Additional enhancements can be achieved by targeting fluid properties, followed by water matrix properties, and finally particle properties, though these factors exhibit a progressively smaller impact on overall water softening improvement. By implementing these prioritized optimization strategies, the operational control strategy for calcium removal will be enhanced, leading to improvements in cost-effectiveness, sustainability, and reliability in drinking water treatment processes.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"26 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143827619","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 : 2025-04-12DOI: 10.1016/j.watres.2025.123643
Muhammad Sohail Asghar, Muhammad Sultan Irshad, Naila Arshad, Maryam Al Huwayz, Muneerah Alomar, Ghazala Maqsood, Muhammad Atif Ali, Uzma Ghanzanfar, Muhammad Sabir, Jinhua Li, Van-Duong Dao, Nang Xuan Ho, Xianbao Wang, Zhiguang Guo
Innovative solutions are needed to meet global water demand and to ensure the sustainable management of saline water resources. Indeed, solar-driven interfacial evaporation systems hold great environmental significance as they offer a sustainable and eco-friendly solution to several pressing issues. Herein, a 3D umbrella-shaped hybrid solar evaporator is innovatively developed by functionalized carbon nanotubes interlinked with metal-organic framework (MOF) nanocubes ZIF-67@CNT is sequentially anchored on cotton fabric with a centralized water supply. Combining these two materials results in a remarkable synergy, where the MOFs may trap and release water molecules (5.75 gg-1), and the CNTs facilitate broadband solar absorption (95 %). The hybrid solar evaporator endows solitary heat accumulation (49.5 °C) under 1k Wm-2 solar irradiance owing to its effective thermal management supported by centralized wicks-inspired water supply as compared to the conventional direct contact structures. More importantly, an efficient evaporation rate (2.1 kg m-2 h-1) was achieved, along with 99.9% rejection efficacy and sustained reproducibility under natural conditions. Meanwhile, the system effectively concentrates and recovers salts from the brine stream, reducing waste and minimizing environmental impact. The sustainable utilization of solar energy reduces the energy cost associated with desalination, contributing to the economic viability of this technology.
{"title":"Functionalized carbon nanotubes interconnected with metal-organic frameworks for in-situ solar-driven evaporation and salt recovery from seawater","authors":"Muhammad Sohail Asghar, Muhammad Sultan Irshad, Naila Arshad, Maryam Al Huwayz, Muneerah Alomar, Ghazala Maqsood, Muhammad Atif Ali, Uzma Ghanzanfar, Muhammad Sabir, Jinhua Li, Van-Duong Dao, Nang Xuan Ho, Xianbao Wang, Zhiguang Guo","doi":"10.1016/j.watres.2025.123643","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123643","url":null,"abstract":"Innovative solutions are needed to meet global water demand and to ensure the sustainable management of saline water resources. Indeed, solar-driven interfacial evaporation systems hold great environmental significance as they offer a sustainable and eco-friendly solution to several pressing issues. Herein, a 3D umbrella-shaped hybrid solar evaporator is innovatively developed by functionalized carbon nanotubes interlinked with metal-organic framework (MOF) nanocubes ZIF-67@CNT is sequentially anchored on cotton fabric with a centralized water supply. Combining these two materials results in a remarkable synergy, where the MOFs may trap and release water molecules (5.75 gg<sup>-1</sup>), and the CNTs facilitate broadband solar absorption (95 %). The hybrid solar evaporator endows solitary heat accumulation (49.5 °C) under 1k Wm<sup>-2</sup> solar irradiance owing to its effective thermal management supported by centralized wicks-inspired water supply as compared to the conventional direct contact structures. More importantly, an efficient evaporation rate (2.1 kg m<sup>-2</sup> h<sup>-1</sup>) was achieved, along with 99.9% rejection efficacy and sustained reproducibility under natural conditions. Meanwhile, the system effectively concentrates and recovers salts from the brine stream, reducing waste and minimizing environmental impact. The sustainable utilization of solar energy reduces the energy cost associated with desalination, contributing to the economic viability of this technology.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"16 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143824892","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 : 2025-04-12DOI: 10.1016/j.watres.2025.123641
Yuanyuan Cao , Yang Liu , Kehui Guo , Wei He , Jin Hur , Huaming Guo
Microplastic-derived dissolved organic matter (MP-DOM), released during ultraviolet-induced aging of microplastics (MPs), has emerged as a critical yet underexplored topic regarding the environmental impacts of MPs. However, the effects of irradiation intensity on the release and molecular diversity of MP-DOM, including plastic additives, remain poorly understood. In this study, the photoaging processes of polystyrene MPs (PS-MPs) were simulated under varying cumulative irradiation (irradiation intensity × irradiation duration) and PS-MPs concentrations (1 − 5 g/L). The PS-derived DOM (PS-DOM) was characterized using fluorescence spectroscopy, Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS), and liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS). After 21 days of irradiation, the amount of leached PS-DOM ranged from 7.76 to 39.40 mg-C/g. Cumulative irradiation significantly accelerated PS-MPs aging and PS-DOM leaching (p < 0.001). Initially, these processes proceeded slowly until the cumulative irradiation exceeded 75 kWh/m2. Beyond this threshold, PS-MPs exhibited substantial size reduction, increased oxidation, and enhanced PS-DOM leaching. FT-ICR MS analysis revealed that PS-DOM contained 30.1 %−31.8 % unique components compared to natural organic matter, with greater degradability at lower PS-MPs concentrations. Furthermore, LC-HRMS identified 13 oxidation products and 25 plastic additives in PS-DOM, with their amounts decreasing as PS-MPs concentrations increased, from 17.05 to 3.24 mg/g and 4.88 to 1.85 mg/g, respectively. Notably, lower PS-MPs concentrations resulted in greater cumulative irradiation per unit mass, intensifying PS-DOM leaching, enhancing degradability, and increasing plastic additives release. This study highlights the environmental implications of per unit cumulative irradiation on MP-DOM leaching and its molecular composition, providing insights into its ecological risks and potential impacts on aquatic systems.
{"title":"Molecular characteristics and plastic additives in dissolved organic matter derived from polystyrene microplastics: Effects of cumulative irradiation and microplastic concentrations","authors":"Yuanyuan Cao , Yang Liu , Kehui Guo , Wei He , Jin Hur , Huaming Guo","doi":"10.1016/j.watres.2025.123641","DOIUrl":"10.1016/j.watres.2025.123641","url":null,"abstract":"<div><div>Microplastic-derived dissolved organic matter (MP-DOM), released during ultraviolet-induced aging of microplastics (MPs), has emerged as a critical yet underexplored topic regarding the environmental impacts of MPs. However, the effects of irradiation intensity on the release and molecular diversity of MP-DOM, including plastic additives, remain poorly understood. In this study, the photoaging processes of polystyrene MPs (PS-MPs) were simulated under varying cumulative irradiation (irradiation intensity × irradiation duration) and PS-MPs concentrations (1 − 5 g/L). The PS-derived DOM (PS-DOM) was characterized using fluorescence spectroscopy, Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS), and liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS). After 21 days of irradiation, the amount of leached PS-DOM ranged from 7.76 to 39.40 mg-C/g. Cumulative irradiation significantly accelerated PS-MPs aging and PS-DOM leaching (<em>p</em> < 0.001). Initially, these processes proceeded slowly until the cumulative irradiation exceeded 75 kWh/m<sup>2</sup>. Beyond this threshold, PS-MPs exhibited substantial size reduction, increased oxidation, and enhanced PS-DOM leaching. FT-ICR MS analysis revealed that PS-DOM contained 30.1 %−31.8 % unique components compared to natural organic matter, with greater degradability at lower PS-MPs concentrations. Furthermore, LC-HRMS identified 13 oxidation products and 25 plastic additives in PS-DOM, with their amounts decreasing as PS-MPs concentrations increased, from 17.05 to 3.24 mg/g and 4.88 to 1.85 mg/g, respectively. Notably, lower PS-MPs concentrations resulted in greater cumulative irradiation per unit mass, intensifying PS-DOM leaching, enhancing degradability, and increasing plastic additives release. This study highlights the environmental implications of per unit cumulative irradiation on MP-DOM leaching and its molecular composition, providing insights into its ecological risks and potential impacts on aquatic systems.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"282 ","pages":"Article 123641"},"PeriodicalIF":11.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143824893","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 : 2025-04-12DOI: 10.1016/j.watres.2025.123642
Wenbo Guo , Xiaoyu Ma , Huiying Yu , Tiansong Song , Zhicheng Li , Hao Qiu , Xinde Cao , Ling Zhao
Nanoplastics (NPs) coexist with microorganisms in global water environmental systems, showing spatial-temporal differentiation. Therefore, studying the behavior of microorganisms previously exposed to NPs is particularly important. With 2,4-dichlorophenol (DCP)-degrading microflora as model microorganisms, this study found that higher dose (10, 100 mg/L) of polystyrene NPs pre-exposure inhibited bacterial DCP degradation prolonging the stagnation period, while lower dose (1 mg/L) of NPs on the contrary stimulated their degradation ability. The degradation delay coefficients (μ) showed a significant positive correlation with the duration of pre-exposure. Specifically, the μ values observed after 1 day, 3 days, and 9 days of pre-exposure to 10 mg/L NPs were 2.5, 2.9, and 3.8, respectively, while those for 100 mg/L NPs were 3.2, 4.0, and 5.1. In contrast, the control group without NPs exhibited a μ value of only 1.9. Pre-exposure caused NPs to enter bacterial cells, leading to oxidative damage, membrane impairment, and potential DNA damage. This carry-over toxicity suppressed the consortium's degradation efficiency of DCP. During the stagnation period, microorganisms were striving to redeem themselves, recovering their abilities of biofilm formation, chemotaxis and motility by upregulating the expression of wspA, mcp, and pilJ gene families, thus reinforcing inter-population regulatory cooperation, thereby restarting the DCP degradation. With the duration of pre-exposure to PS NPs increased, the recovery time required for bacterial communities also lengthened. It is crucial to pay attention to the biological responses to subsequent pollutants triggered by pre-exposure.
{"title":"Nanoplastics pre-exposure to microbial consortium influencing their ability to degrade pollutants: “Stagnation effect” and “Self-recovery”","authors":"Wenbo Guo , Xiaoyu Ma , Huiying Yu , Tiansong Song , Zhicheng Li , Hao Qiu , Xinde Cao , Ling Zhao","doi":"10.1016/j.watres.2025.123642","DOIUrl":"10.1016/j.watres.2025.123642","url":null,"abstract":"<div><div>Nanoplastics (NPs) coexist with microorganisms in global water environmental systems, showing spatial-temporal differentiation. Therefore, studying the behavior of microorganisms previously exposed to NPs is particularly important. With 2,4-dichlorophenol (DCP)-degrading microflora as model microorganisms, this study found that higher dose (10, 100 mg/L) of polystyrene NPs pre-exposure inhibited bacterial DCP degradation prolonging the stagnation period, while lower dose (1 mg/L) of NPs on the contrary stimulated their degradation ability. The degradation delay coefficients (μ) showed a significant positive correlation with the duration of pre-exposure. Specifically, the μ values observed after 1 day, 3 days, and 9 days of pre-exposure to 10 mg/L NPs were 2.5, 2.9, and 3.8, respectively, while those for 100 mg/L NPs were 3.2, 4.0, and 5.1. In contrast, the control group without NPs exhibited a μ value of only 1.9. Pre-exposure caused NPs to enter bacterial cells, leading to oxidative damage, membrane impairment, and potential DNA damage. This carry-over toxicity suppressed the consortium's degradation efficiency of DCP. During the stagnation period, microorganisms were striving to redeem themselves, recovering their abilities of biofilm formation, chemotaxis and motility by upregulating the expression of <em>wspA, mcp,</em> and <em>pilJ</em> gene families, thus reinforcing inter-population regulatory cooperation, thereby restarting the DCP degradation. With the duration of pre-exposure to PS NPs increased, the recovery time required for bacterial communities also lengthened. It is crucial to pay attention to the biological responses to subsequent pollutants triggered by pre-exposure.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"282 ","pages":"Article 123642"},"PeriodicalIF":11.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822940","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}
Excess sludge deep dewatering remains a significant challenge for wastewater treatment sector due to the strong binding of internal bound water within sludge flocs. This study proposes a novel coupling system that synergizes microwave (MW) irradiation with peroxymonosulfate (PMS) activation to enhance the release and removal of internal bound water. By optimizing key parameters, including PMS dosage and MW irradiation time, the results demonstrated that the MW + PMS treatment reduced sludge moisture content from 85.9 % to 64.8 %. In comparison, sole MW or PMS treatments achieved water content reduction to only 84.1 % and 83.1 %, respectively. Electron paramagnetic resonance tests revealed the generation and accumulation of various reactive oxygen species, including ·OH, SO₄-· and ¹O₂, confirming the efficient activation of PMS. These oxidative species play a crucial role in breaking down extracellular polymeric substance network and microbial cell structure, thereby facilitating internal bound water release. Low-field nuclear magnetic resonance characterization further verified the effective conversion of tightly bound water to more mobile forms. Morphological and thermodynamic analysis indicated that the MW + PMS treatment induced a reduction in the sludge particle size and an increase in surface hydrophobicity. These changes resulted in the formation of cracks during filtration, enhancing water permeability and favoring its removal. More importantly, Lewis's acid-base interaction was identified as the leading force contributing to sludge flocculation and dewatering. This study may provide guidance for developing effective sludge deep dewatering technology.
{"title":"Coupling microwave irradiation with peroxymonosulfate activation for sludge deep dewatering via enhancing internal bound water removal","authors":"Chao-Xi Yang, Kai-Yue Dong, Ke-Yu Chen, Wei Yao, Yao-Yao Lu, Jin-Luo Pang, Bao-Cheng Huang, Ren-Cun Jin","doi":"10.1016/j.watres.2025.123636","DOIUrl":"10.1016/j.watres.2025.123636","url":null,"abstract":"<div><div>Excess sludge deep dewatering remains a significant challenge for wastewater treatment sector due to the strong binding of internal bound water within sludge flocs. This study proposes a novel coupling system that synergizes microwave (MW) irradiation with peroxymonosulfate (PMS) activation to enhance the release and removal of internal bound water. By optimizing key parameters, including PMS dosage and MW irradiation time, the results demonstrated that the MW + PMS treatment reduced sludge moisture content from 85.9 % to 64.8 %. In comparison, sole MW or PMS treatments achieved water content reduction to only 84.1 % and 83.1 %, respectively. Electron paramagnetic resonance tests revealed the generation and accumulation of various reactive oxygen species, including ·OH, SO₄<sup>-</sup>· and ¹O₂, confirming the efficient activation of PMS. These oxidative species play a crucial role in breaking down extracellular polymeric substance network and microbial cell structure, thereby facilitating internal bound water release. Low-field nuclear magnetic resonance characterization further verified the effective conversion of tightly bound water to more mobile forms. Morphological and thermodynamic analysis indicated that the MW + PMS treatment induced a reduction in the sludge particle size and an increase in surface hydrophobicity. These changes resulted in the formation of cracks during filtration, enhancing water permeability and favoring its removal. More importantly, Lewis's acid-base interaction was identified as the leading force contributing to sludge flocculation and dewatering. This study may provide guidance for developing effective sludge deep dewatering technology.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"282 ","pages":"Article 123636"},"PeriodicalIF":11.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822968","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 : 2025-04-12DOI: 10.1016/j.watres.2025.123638
Haozhe Ma , Chi Zhang , Ziheng Zhang , Zhiyu Zhou , Yongliang Xu , Mengning Xi , Kecheng Zhu , Hanzhong Jia
The interfacial adsorption, aggregation and deposition processes of nanoplastics (NPs) on clay mineral surfaces critically regulate their environmental mobility, transformation pathways, and ecotoxicological risks in aquatic ecosystems. A quantitative understanding of the nanoscale interfacial processes is essential. This study employs molecular dynamics (MD) simulations and density functional theory (DFT) calculations to elucidate the aggregation and deposition mechanisms of three types of NPs in their pristine and aged states in the nanopore solution of montmorillonite (Mt). In the wet environment, NPs tend to form aggregates in the nanopore and migrate in solution, increasing environmental risk, while in the dry environment, NPs are more likely to deposit on the basal surface to form larger aggregates, consequently reducing their mobility. Results show hydrophobic interactions play as the primary driving force for the aggregation of pristine NPs, and both hydrophilic and hydrophobic interactions contribute to the aggregation of aged NPs. Aged NPs exhibit stronger binding affinity to Mt through mechanism such as Ca²⁺ bridging and hydrogen bonding, compared to their pristine counterparts. DFT calculations further reveal the formation of hydrogen bonds between the hydroxyl groups of aged NPs and the tetrahedral oxygen atoms in Mt. Through atomic-level characterization of interfacial processes, this work establishes a predictive framework for NP environmental behavior by resolving migration dynamics and retention processes in nanopore water.
{"title":"Understanding the structure, distribution, and retention of nanoplastics in montmorillonite nanopore by multi-scale computational simulations","authors":"Haozhe Ma , Chi Zhang , Ziheng Zhang , Zhiyu Zhou , Yongliang Xu , Mengning Xi , Kecheng Zhu , Hanzhong Jia","doi":"10.1016/j.watres.2025.123638","DOIUrl":"10.1016/j.watres.2025.123638","url":null,"abstract":"<div><div>The interfacial adsorption, aggregation and deposition processes of nanoplastics (NPs) on clay mineral surfaces critically regulate their environmental mobility, transformation pathways, and ecotoxicological risks in aquatic ecosystems. A quantitative understanding of the nanoscale interfacial processes is essential. This study employs molecular dynamics (MD) simulations and density functional theory (DFT) calculations to elucidate the aggregation and deposition mechanisms of three types of NPs in their pristine and aged states in the nanopore solution of montmorillonite (Mt). In the wet environment, NPs tend to form aggregates in the nanopore and migrate in solution, increasing environmental risk, while in the dry environment, NPs are more likely to deposit on the basal surface to form larger aggregates, consequently reducing their mobility. Results show hydrophobic interactions play as the primary driving force for the aggregation of pristine NPs, and both hydrophilic and hydrophobic interactions contribute to the aggregation of aged NPs. Aged NPs exhibit stronger binding affinity to Mt through mechanism such as Ca²⁺ bridging and hydrogen bonding, compared to their pristine counterparts. DFT calculations further reveal the formation of hydrogen bonds between the hydroxyl groups of aged NPs and the tetrahedral oxygen atoms in Mt. Through atomic-level characterization of interfacial processes, this work establishes a predictive framework for NP environmental behavior by resolving migration dynamics and retention processes in nanopore water.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"282 ","pages":"Article 123638"},"PeriodicalIF":11.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143824890","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 : 2025-04-12DOI: 10.1016/j.watres.2025.123635
Huaihao Shao , Qiankun Wang , Linlin Wang , Shuangliang Dai , Xin Ye , Xian-zhong Mao
Rapid urbanization has intensified microplastic pollution in many global bays, yet the mechanisms driving microplastic behavior in these environments remain unclear. This study utilized field surveys, statistical analysis, and modeling methods to address this issue. The findings revealed three typical migration patterns of microplastics in bays. Microplastics less dense than seawater were easily transported by currents, drifting extensively throughout the bay, with about 37.2 % temporarily hovering in tidal channels and low-lying areas, ultimately leaving with ebb tides. Spherical microplastics denser than seawater were predominantly concentrated near the shore, primarily lingering in the subsurface layers. In contrast, fibrous microplastics, which are denser than seawater and the most prevalent type in human-impacted bays, displayed a unique behavior. The combined effects of their density and shape resulted in over 80 % being trapped in intertidal ecologically sensitive areas (ESAs). As a result, local ESAs, such as mangroves, bird habitats, and aquaculture, faced significant threats from fibrous microplastics and their sorption complexes associated with Cu, Pb, Cd, and Hg. Additionally, bay sediments acted as a source-sink community for microplastics. In Shenzhen Bay, China, approximately 27.1 × 1011 microplastic items were buried annually in sediments under normal hydrological conditions. However, if annual rainfall exceeded a threshold, these microplastics could be washed into ocean, serving as a source. Coastal raft aquaculture emerged as a significant contributor to marine microplastics, releasing about 3 %-8 % of terrestrial sources in Shenzhen Bay. This study enhances our understanding of microplastic behaviors and risks in bays.
{"title":"Typical migration patterns and fates of microplastics with varying properties in bays and their impacts on coastal ecologically sensitive areas","authors":"Huaihao Shao , Qiankun Wang , Linlin Wang , Shuangliang Dai , Xin Ye , Xian-zhong Mao","doi":"10.1016/j.watres.2025.123635","DOIUrl":"10.1016/j.watres.2025.123635","url":null,"abstract":"<div><div>Rapid urbanization has intensified microplastic pollution in many global bays, yet the mechanisms driving microplastic behavior in these environments remain unclear. This study utilized field surveys, statistical analysis, and modeling methods to address this issue. The findings revealed three typical migration patterns of microplastics in bays. Microplastics less dense than seawater were easily transported by currents, drifting extensively throughout the bay, with about 37.2 % temporarily hovering in tidal channels and low-lying areas, ultimately leaving with ebb tides. Spherical microplastics denser than seawater were predominantly concentrated near the shore, primarily lingering in the subsurface layers. In contrast, fibrous microplastics, which are denser than seawater and the most prevalent type in human-impacted bays, displayed a unique behavior. The combined effects of their density and shape resulted in over 80 % being trapped in intertidal ecologically sensitive areas (ESAs). As a result, local ESAs, such as mangroves, bird habitats, and aquaculture, faced significant threats from fibrous microplastics and their sorption complexes associated with Cu, Pb, Cd, and Hg. Additionally, bay sediments acted as a source-sink community for microplastics. In Shenzhen Bay, China, approximately 27.1 × 10<sup>11</sup> microplastic items were buried annually in sediments under normal hydrological conditions. However, if annual rainfall exceeded a threshold, these microplastics could be washed into ocean, serving as a source. Coastal raft aquaculture emerged as a significant contributor to marine microplastics, releasing about 3 %-8 % of terrestrial sources in Shenzhen Bay. This study enhances our understanding of microplastic behaviors and risks in bays.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"282 ","pages":"Article 123635"},"PeriodicalIF":11.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822941","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 : 2025-04-12DOI: 10.1016/j.watres.2025.123644
Jianhua Kang , Xinlan Guo , Xuancheng Liu , Xianwu Chen , Haiyan Li , Wenjia Hu , Zhaohe Luo
The production and succession of harmful algae blooms (HABs) are attributed more to excessive nutrient concentrations and unbalanced nutrient stoichiometry than to other environmental drivers as the absence of long-term monitoring data. This study analyzed HABs succession patterns and key drivers in Tolo Harbour from 1986 to 2023, leveraging nearly 40 years of data. Effective governmental measures significantly improved water quality, with dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), 5-day biochemical oxygen demand (BOD5), and Escherichia coli (E. coli) concentrations decreasing by 53 %, 80 %, 45 %, and 59 %, respectively. Annual HABs events dropped from 28 to 3, and species diversity declined from 6 to 2. However, toxic species frequency rose from 21 % to 46 %. Dinoflagellates emerged as dominant initial species, with a shift in secondary dominance from diatoms to ochrophytes and toxin types from diarrhetic shellfish poisoning (DSP) to hemolytic toxins (HT). These shifts likely result from combined human and natural influences. Model simulations confirmed that red tide outbreaks, species succession, and shifts in toxin types were driven by declining pH, rising temperatures, unbalanced nitrogen-phosphorus ratios, organic nutrient increases, and algal antagonism. The study emphasizes the importance of the dual reduction of both DIN and DIP, meanwhile inorganic and organic nutrients, suggesting that overly focusing on or distract from one nutrient (e.g., DIP or DON) could lead to unintended ecological consequences, like the proliferation of rare and toxic species. We highlight the combined impacts of climate change (warming and ocean acidification) and anthropogenic activities (nutrient pollution and eutrophication) on HABs, particularly the number and toxin production. This research links policy changes to HABs dynamics, offering strategic recommendations for managing red tides and contribute novel perspectives on the impact of nutrient reduction in comparable bay ecosystems.
{"title":"Long-term successional dynamics and response strategies of harmful algal blooms to environmental changes in Tolo Harbour","authors":"Jianhua Kang , Xinlan Guo , Xuancheng Liu , Xianwu Chen , Haiyan Li , Wenjia Hu , Zhaohe Luo","doi":"10.1016/j.watres.2025.123644","DOIUrl":"10.1016/j.watres.2025.123644","url":null,"abstract":"<div><div>The production and succession of harmful algae blooms (HABs) are attributed more to excessive nutrient concentrations and unbalanced nutrient stoichiometry than to other environmental drivers as the absence of long-term monitoring data. This study analyzed HABs succession patterns and key drivers in Tolo Harbour from 1986 to 2023, leveraging nearly 40 years of data. Effective governmental measures significantly improved water quality, with dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), 5-day biochemical oxygen demand (BOD<sub>5</sub>), and <em>Escherichia coli</em> (<em>E. coli</em>) concentrations decreasing by 53 %, 80 %, 45 %, and 59 %, respectively. Annual HABs events dropped from 28 to 3, and species diversity declined from 6 to 2. However, toxic species frequency rose from 21 % to 46 %. Dinoflagellates emerged as dominant initial species, with a shift in secondary dominance from diatoms to ochrophytes and toxin types from diarrhetic shellfish poisoning (DSP) to hemolytic toxins (HT). These shifts likely result from combined human and natural influences. Model simulations confirmed that red tide outbreaks, species succession, and shifts in toxin types were driven by declining pH, rising temperatures, unbalanced nitrogen-phosphorus ratios, organic nutrient increases, and algal antagonism. The study emphasizes the importance of the dual reduction of both DIN and DIP, meanwhile inorganic and organic nutrients, suggesting that overly focusing on or distract from one nutrient (e.g., DIP or DON) could lead to unintended ecological consequences, like the proliferation of rare and toxic species. We highlight the combined impacts of climate change (warming and ocean acidification) and anthropogenic activities (nutrient pollution and eutrophication) on HABs, particularly the number and toxin production. This research links policy changes to HABs dynamics, offering strategic recommendations for managing red tides and contribute novel perspectives on the impact of nutrient reduction in comparable bay ecosystems.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"282 ","pages":"Article 123644"},"PeriodicalIF":11.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143824911","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 : 2025-04-12DOI: 10.1016/j.watres.2025.123640
Muhammad Junaid Ali Asif Raja , Adil Sultan , Chuan-Yu Chang , Chi-Min Shu , Muhammad Shoaib , Adiqa Kausar Kiani , Muhammad Asif Zahoor Raja
Artificial intelligence has transformed both plankton dynamics and hazardous material management under toxic environments by enhanced hazard prediction in detecting how toxins affect plankton population and potentially uncovering greater depth of ecological insights. In proposed study, nonlinear autoregressive exogenous neural network coupled with Levenberg-Marquardt is efficaciously selected to model fractional order toxin plankton (FOTP) system asserting the phytoplankton and zooplankton dynamics in aquatic environment under influence of environmental toxins. The fractional differential ecological TP system incorporates density population of phytoplankton, zooplankton and environmental toxins exacted by fractional Adams multistep predictor-corrector method across arbitrary fractional order cases varying intrinsic growth rates of phytoplankton and zooplankton, zooplankton carrying capacity, phytoplankton toxin release, fish predation parameters (half-saturation constant and maximum rate), environmental toxin depletion, and dynamic phytoplankton carrying capacity. Synthetic datasets were split into training, testing, and validation subsets to model the FOTP system using an intelligent neurocomputing paradigm. The proficiency of the selected neural networks is demonstrated by performance metrics—MSE convergence, time-series fitness patterns, regression reports, error histograms and correlation analyses—while comparative analysis with numerical outcomes and absolute error plots underscores the robustness and stability of the neurocomputing architecture. Rigorous analysis on single step and multistep ahead predictors with error of order 10−5 further highlights the efficacy of employed neurocomputing design for optimal and precise forecasting of intricate FOTP system dynamics. This study demonstrates that intelligent computing can effectively forecast FOTP dynamics and serve as a framework for addressing aquatic ecological hazards.
{"title":"Design of a fractional-order environmental toxin-plankton system in aquatic ecosystems: A novel machine predictive expedition with nonlinear autoregressive neuroarchitectures","authors":"Muhammad Junaid Ali Asif Raja , Adil Sultan , Chuan-Yu Chang , Chi-Min Shu , Muhammad Shoaib , Adiqa Kausar Kiani , Muhammad Asif Zahoor Raja","doi":"10.1016/j.watres.2025.123640","DOIUrl":"10.1016/j.watres.2025.123640","url":null,"abstract":"<div><div>Artificial intelligence has transformed both plankton dynamics and hazardous material management under toxic environments by enhanced hazard prediction in detecting how toxins affect plankton population and potentially uncovering greater depth of ecological insights. In proposed study, nonlinear autoregressive exogenous neural network coupled with Levenberg-Marquardt is efficaciously selected to model fractional order toxin plankton (FOTP) system asserting the phytoplankton and zooplankton dynamics in aquatic environment under influence of environmental toxins. The fractional differential ecological TP system incorporates density population of phytoplankton, zooplankton and environmental toxins exacted by fractional Adams multistep predictor-corrector method across arbitrary fractional order cases varying intrinsic growth rates of phytoplankton and zooplankton, zooplankton carrying capacity, phytoplankton toxin release, fish predation parameters (half-saturation constant and maximum rate), environmental toxin depletion, and dynamic phytoplankton carrying capacity. Synthetic datasets were split into training, testing, and validation subsets to model the FOTP system using an intelligent neurocomputing paradigm. The proficiency of the selected neural networks is demonstrated by performance metrics—MSE convergence, time-series fitness patterns, regression reports, error histograms and correlation analyses—while comparative analysis with numerical outcomes and absolute error plots underscores the robustness and stability of the neurocomputing architecture. Rigorous analysis on single step and multistep ahead predictors with error of order 10<sup>−5</sup> further highlights the efficacy of employed neurocomputing design for optimal and precise forecasting of intricate FOTP system dynamics. This study demonstrates that intelligent computing can effectively forecast FOTP dynamics and serve as a framework for addressing aquatic ecological hazards.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"282 ","pages":"Article 123640"},"PeriodicalIF":11.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143824891","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 : 2025-04-12DOI: 10.1016/j.watres.2025.123639
Sungeun Lim, Yufei Wu, William A. Mitch
Nitrogen heterocycles are important structural components in biomolecules and anthropogenic chemicals, yet their transformation during chlorine disinfection remains poorly understood. This study investigated chlorination kinetics and product formation for six nitrogen heterocycles of increasing structural complexity, including cyclic amides (2-piperidone, glutarimide, 5,6-dihydrouracil) and uracil derivatives (uracil, uridine, and 1,3-dimethyluracil) to determine how structural variations influence reaction pathways. Apparent second-order rate constants varied widely from 9.2 × 10–3 M-1 s-1 (2-piperidone) to >103 M-1 s-1 (uracil, uridine), largely influenced by the nitrogen pKa values. Chlorination proceeded through initial N-chlorination, forming organic chloramides. While most organic chloramides were transient, that derived from 2-piperidone persisted for days under excess chlorine conditions. For saturated heterocyclic imides (glutarimide, 5,6-dihydrouracil), hydrolysis of the organic chloramides between the imide nitrogen and an adjacent acyl group rapidly formed ring-opened organic acids. Among uracil derivatives, chlorine added across the double bond. For uracil, the resulting 5-chlorouracil rapidly fragmented between the C-4 and C-5 position to release trichloroacetaldehyde at ∼100 % yield. Substitution at heterocyclic nitrogens in uridine and 1,3-dimethyluracil limited such fragmentation, forming more stable C-chlorinated heterocyclic or ring-opened products. The reaction patterns observed for these six nitrogen heterocycles were further validated using phthalimide and thymine, demonstrating the broader applicability of the identified reaction trends. These findings enhance our understanding of nitrogen heterocycle chlorination mechanisms and their implications for drinking water disinfection, offering insights into minimizing the formation of potentially harmful DBPs during chlorination.
{"title":"Transformation of cyclic amides and uracil-derived nitrogen heterocycles during chlorination","authors":"Sungeun Lim, Yufei Wu, William A. Mitch","doi":"10.1016/j.watres.2025.123639","DOIUrl":"10.1016/j.watres.2025.123639","url":null,"abstract":"<div><div>Nitrogen heterocycles are important structural components in biomolecules and anthropogenic chemicals, yet their transformation during chlorine disinfection remains poorly understood. This study investigated chlorination kinetics and product formation for six nitrogen heterocycles of increasing structural complexity, including cyclic amides (2-piperidone, glutarimide, 5,6-dihydrouracil) and uracil derivatives (uracil, uridine, and 1,3-dimethyluracil) to determine how structural variations influence reaction pathways. Apparent second-order rate constants varied widely from 9.2 × 10<sup>–3</sup> M<sup>-1</sup> s<sup>-1</sup> (2-piperidone) to >10<sup>3</sup> M<sup>-1</sup> s<sup>-1</sup> (uracil, uridine), largely influenced by the nitrogen pK<sub>a</sub> values. Chlorination proceeded through initial <em>N</em>-chlorination, forming organic chloramides. While most organic chloramides were transient, that derived from 2-piperidone persisted for days under excess chlorine conditions. For saturated heterocyclic imides (glutarimide, 5,6-dihydrouracil), hydrolysis of the organic chloramides between the imide nitrogen and an adjacent acyl group rapidly formed ring-opened organic acids. Among uracil derivatives, chlorine added across the double bond. For uracil, the resulting 5-chlorouracil rapidly fragmented between the C-4 and C-5 position to release trichloroacetaldehyde at ∼100 % yield. Substitution at heterocyclic nitrogens in uridine and 1,3-dimethyluracil limited such fragmentation, forming more stable C-chlorinated heterocyclic or ring-opened products. The reaction patterns observed for these six nitrogen heterocycles were further validated using phthalimide and thymine, demonstrating the broader applicability of the identified reaction trends. These findings enhance our understanding of nitrogen heterocycle chlorination mechanisms and their implications for drinking water disinfection, offering insights into minimizing the formation of potentially harmful DBPs during chlorination.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"282 ","pages":"Article 123639"},"PeriodicalIF":11.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822942","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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