Pub Date : 2025-02-14DOI: 10.1016/j.watres.2025.123282
Yuanna Zhang, Wenjun Sun, Wenxuan Yin
The widespread application of UV/H2O2 is limited by the empirical operational practices, which can lead to excessive energy, chemical input and the generation of uncontrollable by-products. This study presents a precise regulation approach based on the characteristics of free radical generation/reaction and the chemical transformation of organics, assessed through a pilot experiment. The findings indicated that increasing H2O2 dosage was more effective than increasing UV dose in enhancing •OH generation and pollutant removal. As the H2O2 dosage and UV dose increased, the relative influence of water quality on pollutant removal gradually diminished. Dissolved organic matter (DOM) in the water quality background accounted for the largest proportion of •OH scavenging (76.4%) and the most complex component. Moreover, changes in operating conditions were accompanied by the uncontrollable production of low-molecular-weight (LMW) DOM. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) revealed the chemical transformation of LMW DOM at the molecular level. Higher H₂O₂ dosages triggered more extensive oxidative degradation, resulting in more complex effluent compositions. Considering treatment efficiency, energy consumption, and effluent product composition, H₂O₂ dosages of 5–10 mg/L and UV doses of 350–450 mJ/cm² were identified as optimal. This research contributes to the efficient purification of organic micropollutants in water using UV/H2O2 technology with low energy consumption, minimal chemical input, and relatively controllable by-products.
{"title":"Precise Regulation of UV/H2O2 Processes: •OH generation/reaction and DOM transformation as the main free radical scavenger","authors":"Yuanna Zhang, Wenjun Sun, Wenxuan Yin","doi":"10.1016/j.watres.2025.123282","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123282","url":null,"abstract":"The widespread application of UV/H<sub>2</sub>O<sub>2</sub> is limited by the empirical operational practices, which can lead to excessive energy, chemical input and the generation of uncontrollable by-products. This study presents a precise regulation approach based on the characteristics of free radical generation/reaction and the chemical transformation of organics, assessed through a pilot experiment. The findings indicated that increasing H<sub>2</sub>O<sub>2</sub> dosage was more effective than increasing UV dose in enhancing •OH generation and pollutant removal. As the H<sub>2</sub>O<sub>2</sub> dosage and UV dose increased, the relative influence of water quality on pollutant removal gradually diminished. Dissolved organic matter (DOM) in the water quality background accounted for the largest proportion of •OH scavenging (76.4%) and the most complex component. Moreover, changes in operating conditions were accompanied by the uncontrollable production of low-molecular-weight (LMW) DOM. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) revealed the chemical transformation of LMW DOM at the molecular level. Higher H₂O₂ dosages triggered more extensive oxidative degradation, resulting in more complex effluent compositions. Considering treatment efficiency, energy consumption, and effluent product composition, H₂O₂ dosages of 5–10 mg/L and UV doses of 350–450 mJ/cm² were identified as optimal. This research contributes to the efficient purification of organic micropollutants in water using UV/H<sub>2</sub>O<sub>2</sub> technology with low energy consumption, minimal chemical input, and relatively controllable by-products.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"100 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418262","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 : 2025-02-13DOI: 10.1016/j.watres.2025.123281
Wancheng Cai, Cheng Ye, Feiyang Ao, Zuxin Xu, Wenhai Chu
Fluorescence excitation-emission matrix (FEEM) spectroscopy is increasingly utilized in water quality monitoring due to its rapid, sensitive, and non-destructive measurement capabilities. The integration of machine learning (ML) techniques with FEEM offers a powerful approach to enhance data interpretation and improve monitoring efficiency. This review systematically examines the application of ML-FEEM in urban water systems across three primary tasks of ML: classification, regression, and pattern recognition. Contributed by the effectiveness of ML in nonlinear and high dimensional data analysis, ML-FEEM achieved superior accuracy and efficiency in pollutant qualification and quantification. The fluorescence features extracted through ML are more representative and hold potential for generating new FEEM samples. Additionally, the rich visualization capabilities of ML-FEEM facilitate the exploration of the migration and transformation of dissolved organic matter in water. This review underscores the importance of leveraging the latest ML advancements to uncover hidden information within FEEM data, and advocates for the use of pattern recognition methods, represented by self-organizing map, to further elucidate the behavior of pollutants in aquatic environments. Despite notable advancements, several issues require careful consideration, including the portable or online setups for FEEM collection, the standardized pretreatment processes for FEEM analysis, and the smart feedback of long-term FEEM governance.
{"title":"Emerging Applications of Fluorescence Excitation-Emission Matrix with Machine Learning for Water Quality Monitoring: A Systematic Review","authors":"Wancheng Cai, Cheng Ye, Feiyang Ao, Zuxin Xu, Wenhai Chu","doi":"10.1016/j.watres.2025.123281","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123281","url":null,"abstract":"Fluorescence excitation-emission matrix (FEEM) spectroscopy is increasingly utilized in water quality monitoring due to its rapid, sensitive, and non-destructive measurement capabilities. The integration of machine learning (ML) techniques with FEEM offers a powerful approach to enhance data interpretation and improve monitoring efficiency. This review systematically examines the application of ML-FEEM in urban water systems across three primary tasks of ML: classification, regression, and pattern recognition. Contributed by the effectiveness of ML in nonlinear and high dimensional data analysis, ML-FEEM achieved superior accuracy and efficiency in pollutant qualification and quantification. The fluorescence features extracted through ML are more representative and hold potential for generating new FEEM samples. Additionally, the rich visualization capabilities of ML-FEEM facilitate the exploration of the migration and transformation of dissolved organic matter in water. This review underscores the importance of leveraging the latest ML advancements to uncover hidden information within FEEM data, and advocates for the use of pattern recognition methods, represented by self-organizing map, to further elucidate the behavior of pollutants in aquatic environments. Despite notable advancements, several issues require careful consideration, including the portable or online setups for FEEM collection, the standardized pretreatment processes for FEEM analysis, and the smart feedback of long-term FEEM governance.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"2 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417919","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}
Carbon dioxide (CO2) injection has been proposed as a strategy for carbon sequestration, while uncertainties persist regarding its effects on groundwater. Concerns have been raised that CO2 mineralization and sequestration could potentially lead to groundwater contamination. However, our study demonstrates its capability to mitigate pollution. The injection of CO2 facilitates the rapid dissolution of minerals, releasing Ca(II), Mg(II), and Fe(II) and forming secondary carbonate minerals, such as CaCO3, MgCO3, and FeCO3. The in-situ generated FeCO3 can activate oxygen to produce hydroxyl radicals (•OH) under oxic condition, thereby enhancing the degradation of emerging organic contaminants in groundwater, such as 2,4,6-tribromophenol, flurbiprofen, diclofenac, carbamazepine, phenol, and sulfamethoxazole. Mechanism studies suggest that this process is enhanced by the conversion of in-situ formed FeCO3 into a two-dimensional goethite nanosheet structure, which provides a larger specific surface area and enables more Fe(II) to be adsorbed on the mineral surface. The formation of Fe-O coordination bonds effectively reduces the loss of •OH at the interfacial reaction layer. The study further distinguishes and quantifies the contributions of different Fe(II) forms to •OH generation. The transformation pathways of the six contaminants and the toxicity of their intermediates are also analyzed. CaCO3 and MgCO3 do not exhibit the ability to degrade pollutants, but play a role in carbon mineralization. This work reveals that secondary minerals generated through the CO2 mineralization and sequestration process display simultaneous capabilities of contaminant degradation and carbon fixation. Such activities are pivotal not only for the environmental fate and transformation of emerging contaminants in groundwater but also for regulating the carbon cycle.
{"title":"CO2 geological sequestration can remove emerging contaminants in groundwater: The important role of secondary mineral carbonates","authors":"Zhongjie Cui, Xuejie Zhang, Bingbing Hu, Liandong Zhu, Li-Zhi Huang","doi":"10.1016/j.watres.2025.123293","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123293","url":null,"abstract":"Carbon dioxide (CO<sub>2</sub>) injection has been proposed as a strategy for carbon sequestration, while uncertainties persist regarding its effects on groundwater. Concerns have been raised that CO<sub>2</sub> mineralization and sequestration could potentially lead to groundwater contamination. However, our study demonstrates its capability to mitigate pollution. The injection of CO<sub>2</sub> facilitates the rapid dissolution of minerals, releasing Ca(II), Mg(II), and Fe(II) and forming secondary carbonate minerals, such as CaCO<sub>3</sub>, MgCO<sub>3</sub>, and FeCO<sub>3</sub>. The in-situ generated FeCO<sub>3</sub> can activate oxygen to produce hydroxyl radicals (•OH) under oxic condition, thereby enhancing the degradation of emerging organic contaminants in groundwater, such as 2,4,6-tribromophenol, flurbiprofen, diclofenac, carbamazepine, phenol, and sulfamethoxazole. Mechanism studies suggest that this process is enhanced by the conversion of in-situ formed FeCO<sub>3</sub> into a two-dimensional goethite nanosheet structure, which provides a larger specific surface area and enables more Fe(II) to be adsorbed on the mineral surface. The formation of Fe-O coordination bonds effectively reduces the loss of •OH at the interfacial reaction layer. The study further distinguishes and quantifies the contributions of different Fe(II) forms to •OH generation. The transformation pathways of the six contaminants and the toxicity of their intermediates are also analyzed. CaCO<sub>3</sub> and MgCO<sub>3</sub> do not exhibit the ability to degrade pollutants, but play a role in carbon mineralization. This work reveals that secondary minerals generated through the CO<sub>2</sub> mineralization and sequestration process display simultaneous capabilities of contaminant degradation and carbon fixation. Such activities are pivotal not only for the environmental fate and transformation of emerging contaminants in groundwater but also for regulating the carbon cycle.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"10 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417916","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 : 2025-02-13DOI: 10.1016/j.watres.2025.123271
Tianming Huang
Deuterium excess (defined as d=δ2H-8*δ18O) decreases during evaporation and is a potential tool for determining the contribution of the evapoconcentration of a given water body using the relationship between deuterium excess and salinity. The initial deuterium excess in a study area can be obtained from the local meteoric water line or initial recharge water. The present comment reveals recently published misuse of the approach and offers reasonable results.
{"title":"Comment on “Tracking nitrate and sulfate sources in groundwater of an urbanized valley using a multi-tracer approach combined with a Bayesian isotope mixing model”, published by J. A. Torres-Martínez et al. [Water Research 182 (2020) 115962]","authors":"Tianming Huang","doi":"10.1016/j.watres.2025.123271","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123271","url":null,"abstract":"Deuterium excess (defined as <em>d</em>=δ<sup>2</sup>H-8*δ<sup>18</sup>O) decreases during evaporation and is a potential tool for determining the contribution of the evapoconcentration of a given water body using the relationship between deuterium excess and salinity. The initial deuterium excess in a study area can be obtained from the local meteoric water line or initial recharge water. The present comment reveals recently published misuse of the approach and offers reasonable results.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"34 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417920","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 : 2025-02-13DOI: 10.1016/j.watres.2025.123266
Wenjian Lao , Xiaoyan Shang , Shuiqiang Yu , Huiquan Xiao , Yingying Lou , Cuihua Song , Jinmao You
Passive sampling methods can provide valuable insights for monitoring hydrophobic organic compounds (HOCs) in aquatic environments. As the list of target HOCs expands, there is an increasing demand for passive samplers that can detect a broader range of these compounds. This study aimed to assess the efficacy of a three-layer co-extruded polyethylene/ethylene vinyl acetate (TLC-EVA) film alongside three existing materials (polyethylene (PE), polydimethylsiloxane (PDMS), and poly(methyl methacrylate) (PMMA)) for passive sampling of carbazole and five halogenated carbazoles (PHCZs), a group of dioxin-like chemicals, in water. The films were calibrated through batch experiments to determine the partition coefficients between the polymer and water (KPW). The performance of the samplers and the presence of PHCZs were evaluated through 7- and 14-day exposures in the Xiaoyi River, which flows through Qufu City, China. The logKPW values varied significantly among the compounds and were generally consistent across the four films, ranging from 2.73 to 4.14 for EVA, 2.65 to 4.21 for PE, 2.85 to 3.98 for PMMA, and 2.62 to 4.22 for PDMS. These findings indicate that the films can effectively function as passive samplers for PHCZs. Additionally, a comparison of logKPW results with physicochemical parameters (logKOW and logKOC) highlighted the negative impact of halogen substituents and steric hindrance on sorption, particularly for 1,3,6,8-tetrabromocarbazole. The passive sampling reached equilibrium within the 7-day exposure period, with all PHCZs detected in the river water. Increased concentrations at urban and wastewater treatment plant outlet sampling sites suggested specific sources of PHCZs. Our results advocate for the application of multilayer co-extrusion films as a novel material for passive sampling of HOCs.
{"title":"Evaluation of multilayer co-extrusion film and other three plastic membranes as passive samplers for determination of polyhalogenated carbazoles in water","authors":"Wenjian Lao , Xiaoyan Shang , Shuiqiang Yu , Huiquan Xiao , Yingying Lou , Cuihua Song , Jinmao You","doi":"10.1016/j.watres.2025.123266","DOIUrl":"10.1016/j.watres.2025.123266","url":null,"abstract":"<div><div>Passive sampling methods can provide valuable insights for monitoring hydrophobic organic compounds (HOCs) in aquatic environments. As the list of target HOCs expands, there is an increasing demand for passive samplers that can detect a broader range of these compounds. This study aimed to assess the efficacy of a three-layer co-extruded polyethylene/ethylene vinyl acetate (TLC-EVA) film alongside three existing materials (polyethylene (PE), polydimethylsiloxane (PDMS), and poly(methyl methacrylate) (PMMA)) for passive sampling of carbazole and five halogenated carbazoles (PHCZs), a group of dioxin-like chemicals, in water. The films were calibrated through batch experiments to determine the partition coefficients between the polymer and water (<em>K<sub>PW</sub></em>). The performance of the samplers and the presence of PHCZs were evaluated through 7- and 14-day exposures in the Xiaoyi River, which flows through Qufu City, China. The log<em>K<sub>PW</sub></em> values varied significantly among the compounds and were generally consistent across the four films, ranging from 2.73 to 4.14 for EVA, 2.65 to 4.21 for PE, 2.85 to 3.98 for PMMA, and 2.62 to 4.22 for PDMS. These findings indicate that the films can effectively function as passive samplers for PHCZs. Additionally, a comparison of log<em>K<sub>PW</sub></em> results with physicochemical parameters (log<em>K<sub>OW</sub></em> and log<em>K<sub>OC</sub></em>) highlighted the negative impact of halogen substituents and steric hindrance on sorption, particularly for 1,3,6,8-tetrabromocarbazole. The passive sampling reached equilibrium within the 7-day exposure period, with all PHCZs detected in the river water. Increased concentrations at urban and wastewater treatment plant outlet sampling sites suggested specific sources of PHCZs. Our results advocate for the application of multilayer co-extrusion films as a novel material for passive sampling of HOCs.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"276 ","pages":"Article 123266"},"PeriodicalIF":11.4,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402595","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 : 2025-02-13DOI: 10.1016/j.watres.2025.123298
Yi Zhang, Xudong Liu, Jia Feng, Shulian Xie, Junping Lv
The technology of microalgae-bacteria consortia (MBC) for wastewater treatment is currently facing a variety of challenges. One of the main issues is the construction of structurally and functionally stable symbiont. Ca2+ may be involved in this process, but the underlying mechanism is not well understood. Here the response of MBC to the regulation of Ca2+ was systematically explored from the perspectives of extracellular polymeric substances (EPS) and bacterial communities. The results showed that the exogenous addition of Ca2+ (10-50 mM) not only promoted the production of extracellular polysaccharides and proteins of MBC, but also increased the proportion of some functional groups and components of EPS, such as C=O and α-helix. The change of EPS characteristics was conducive to provide more sites for bining Ca2+, which in turn favored the formation of compact MBC via overcoming electrostatic repulsive effect. Besides, the supplementation of Ca2+ favored the recruitment of more EPS-producing bacteria (such as Rhodobacter, Pedobacter, Rhizorhapis, and Sphingopyxis) and indole acetic acid producing bacteria (such as Hydrogenophaga and Agromyces). The enrichment of these functional bacteria not only promoted the adhesion between bacteria and microalgae, but also promoted the growth of symbiotic microalgae, which contributed to the formation of stable large-sized MBC. The change in structure and function of MBC was ultimately reflected in the improved performance in treating municipal wastewater. The findings of this study provided insights into the mechanism underlying the enhanced performance of MBC for wastewater treatment under the influence of Ca2+.
{"title":"Ca2+ enhanced the wastewater treatment performance of microalgal-bacterial consortia: response of extracellular polymeric substances and bacterial communities","authors":"Yi Zhang, Xudong Liu, Jia Feng, Shulian Xie, Junping Lv","doi":"10.1016/j.watres.2025.123298","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123298","url":null,"abstract":"The technology of microalgae-bacteria consortia (MBC) for wastewater treatment is currently facing a variety of challenges. One of the main issues is the construction of structurally and functionally stable symbiont. Ca<sup>2+</sup> may be involved in this process, but the underlying mechanism is not well understood. Here the response of MBC to the regulation of Ca<sup>2+</sup> was systematically explored from the perspectives of extracellular polymeric substances (EPS) and bacterial communities. The results showed that the exogenous addition of Ca<sup>2+</sup> (10-50 mM) not only promoted the production of extracellular polysaccharides and proteins of MBC, but also increased the proportion of some functional groups and components of EPS, such as C=O and α-helix. The change of EPS characteristics was conducive to provide more sites for bining Ca<sup>2+</sup>, which in turn favored the formation of compact MBC via overcoming electrostatic repulsive effect. Besides, the supplementation of Ca<sup>2+</sup> favored the recruitment of more EPS-producing bacteria (such as <em>Rhodobacter, Pedobacter, Rhizorhapis</em>, and <em>Sphingopyxis</em>) and indole acetic acid producing bacteria (such as <em>Hydrogenophaga</em> and <em>Agromyces</em>). The enrichment of these functional bacteria not only promoted the adhesion between bacteria and microalgae, but also promoted the growth of symbiotic microalgae, which contributed to the formation of stable large-sized MBC. The change in structure and function of MBC was ultimately reflected in the improved performance in treating municipal wastewater. The findings of this study provided insights into the mechanism underlying the enhanced performance of MBC for wastewater treatment under the influence of Ca<sup>2+</sup>.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"23 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417917","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 : 2025-02-13DOI: 10.1016/j.watres.2025.123287
Diyuan Wang, Francis L. de los Reyes, Joel J. Ducoste
Hydrodynamic cavitation (HC) has recently emerged as an effective method for disrupting microalgae cells with lower energy consumption compared to traditional mechanical methods like bead milling and ultrasonication. However, the efficiency and energy utilization of HC can vary depending on the microalgae species and operating conditions. To assess the efficacy of HC and quantify the extent of cellular damage at the cell level, we designed a bench-top cavitation system to investigate the time-dependent responses of the microalgae Dunaliella viridis to multiple HC passes. We evaluated cell disruption efficiency by monitoring cell concentration using a cell counter and analyzing cell size distribution and whole cell counts via flow cytometry. Additionally, we assessed cell viability, metabolic activity, and reactive oxygen species (ROS) levels using the fluorescent probes fluorescein diacetate (FDA), erythrosine B (EB), and 2′,7′-dichlorofluorescein diacetate (DCFDA). We further analyzed cell chlorophyll autofluorescence and the kinetics of overall cell inactivation. Our results demonstrated that HC effectively disrupted and inactivated cells, approximating pseudo-first-order kinetics. However, the cell inactivation rate and energy utilization efficiency declined rapidly in the early stages, likely due to the accumulation of cell debris. A P-factor model incorporating two first-order rate constants was then developed to better predict the cell inactivation kinetics and further demonstrated that cavitation number alone was insufficient to characterize the dynamic change in the inactivation rate during cavitation. To maintain high inactivation efficiency, it is recommended to keep the cell debris fraction below 10-20%. HC was found to inactivate cells by rupturing cell membranes, leading to the rapid release of intracellular contents such as esterase and chlorophyll. HC did not affect intracellular esterase activity or chlorophyll content in cells with intact membranes, but the endogenous ROS levels in viable cells were reduced. The mechanisms of cell damage were discussed in detail. For bioproduct harvesting, cell membrane integrity is suggested as a key physiological endpoint for optimizing HC treatment protocols.
{"title":"Enhancing Microalgae Cell Inactivation Through Hydrodynamic Cavitation: Insights from Flow Cytometry Analysis","authors":"Diyuan Wang, Francis L. de los Reyes, Joel J. Ducoste","doi":"10.1016/j.watres.2025.123287","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123287","url":null,"abstract":"Hydrodynamic cavitation (HC) has recently emerged as an effective method for disrupting microalgae cells with lower energy consumption compared to traditional mechanical methods like bead milling and ultrasonication. However, the efficiency and energy utilization of HC can vary depending on the microalgae species and operating conditions. To assess the efficacy of HC and quantify the extent of cellular damage at the cell level, we designed a bench-top cavitation system to investigate the time-dependent responses of the microalgae <em>Dunaliella viridis</em> to multiple HC passes. We evaluated cell disruption efficiency by monitoring cell concentration using a cell counter and analyzing cell size distribution and whole cell counts via flow cytometry. Additionally, we assessed cell viability, metabolic activity, and reactive oxygen species (ROS) levels using the fluorescent probes fluorescein diacetate (FDA), erythrosine B (EB), and 2′,7′-dichlorofluorescein diacetate (DCFDA). We further analyzed cell chlorophyll autofluorescence and the kinetics of overall cell inactivation. Our results demonstrated that HC effectively disrupted and inactivated cells, approximating pseudo-first-order kinetics. However, the cell inactivation rate and energy utilization efficiency declined rapidly in the early stages, likely due to the accumulation of cell debris. A <em>P</em>-factor model incorporating two first-order rate constants was then developed to better predict the cell inactivation kinetics and further demonstrated that cavitation number alone was insufficient to characterize the dynamic change in the inactivation rate during cavitation. To maintain high inactivation efficiency, it is recommended to keep the cell debris fraction below 10-20%. HC was found to inactivate cells by rupturing cell membranes, leading to the rapid release of intracellular contents such as esterase and chlorophyll. HC did not affect intracellular esterase activity or chlorophyll content in cells with intact membranes, but the endogenous ROS levels in viable cells were reduced. The mechanisms of cell damage were discussed in detail. For bioproduct harvesting, cell membrane integrity is suggested as a key physiological endpoint for optimizing HC treatment protocols.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"8 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143401757","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}
Stacking two-dimensional (2D) nanosheets into lamellar membranes holds great promise in the selective separation of Li+ and Mg2+ from salt-lake brines, but revealing the intrinsic effect of nanosheet properties on the ion transport remains a great challenge. The primary reasons are inevitable emerging defects and changes in surface functional groups during nanosheet preparation. Here, we successfully demonstrated the intrinsic dependence of ion separation on the size and layer charge density of 2D building blocks using defect-free and inherently permanent charged clay nanosheets. The smaller-sized nanosheets readily assembled into lamellar membranes with narrower nanochannel dimension, which facilitated the steric hindrance effect to improve the Li+/Mg2+ selectivity. Experiments and calculations demonstrated the layer charge density-dependent ion separation as well, for which a novel mechanism of intrinsic selective separation driven from the energy barrier difference of ions transport was proposed. Based on the “internal” regulation of the intrinsic nanosheet properties, MMT membranes realized stable and efficient Li+/Mg2+ separation under extreme conditions, multi-cycle and long-term experiments, with an optimal SLi/Mg of 38.9, superior to most of the reported state-of-the-art membranes. This work reveals the intrinsic interplay of nanosheet properties tuning the ion transport and separation, which will inspire the design and development of advanced 2D lamellar membranes, particularly for sustainable and environmental energy exploitation.
{"title":"Intrinsic roles of nanosheet characteristics in two-dimensional montmorillonite membranes for efficient Li+/Mg2+ separation","authors":"Xiongrui Jiang , Lingjie Zhang , Yanhui Miao , Licai Chen , Jiaoyan Liu , Tingting Zhang , Shuai Cheng , Yuhan Song , Yunliang Zhao","doi":"10.1016/j.watres.2025.123291","DOIUrl":"10.1016/j.watres.2025.123291","url":null,"abstract":"<div><div>Stacking two-dimensional (2D) nanosheets into lamellar membranes holds great promise in the selective separation of Li<sup>+</sup> and Mg<sup>2+</sup> from salt-lake brines, but revealing the intrinsic effect of nanosheet properties on the ion transport remains a great challenge. The primary reasons are inevitable emerging defects and changes in surface functional groups during nanosheet preparation. Here, we successfully demonstrated the intrinsic dependence of ion separation on the size and layer charge density of 2D building blocks using defect-free and inherently permanent charged clay nanosheets. The smaller-sized nanosheets readily assembled into lamellar membranes with narrower nanochannel dimension, which facilitated the steric hindrance effect to improve the Li<sup>+</sup>/Mg<sup>2+</sup> selectivity. Experiments and calculations demonstrated the layer charge density-dependent ion separation as well, for which a novel mechanism of intrinsic selective separation driven from the energy barrier difference of ions transport was proposed. Based on the “internal” regulation of the intrinsic nanosheet properties, MMT membranes realized stable and efficient Li<sup>+</sup>/Mg<sup>2+</sup> separation under extreme conditions, multi-cycle and long-term experiments, with an optimal S<sub>Li/Mg</sub> of 38.9, superior to most of the reported state-of-the-art membranes. This work reveals the intrinsic interplay of nanosheet properties tuning the ion transport and separation, which will inspire the design and development of advanced 2D lamellar membranes, particularly for sustainable and environmental energy exploitation.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"276 ","pages":"Article 123291"},"PeriodicalIF":11.4,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143401756","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 : 2025-02-13DOI: 10.1016/j.watres.2025.123289
Shiyu Xie , Yuanyuan Su , Dan Qi , Fei Liu , Liu Gao , Ruiqi Bao , Xing Cheng , Xubing Lin , Tingting Zhang , Licheng Peng
Previous studies on microplastics (MPs) distribution have predominantly focused on water bodies within specific regions, with limited emphasis on the contributions of MPs directly discharged from functional zones surrounding isolated island. This study addressed this gap by investigating the occurrence and distribution of MPs in water and sediment directly discharged into the adjacent coast of Hainan Island, a geographically isolated and ecologically sensitive region in the South China Sea. Based on the sampling from 40 typical sewage outlets (affiliated to five functional zones, i.e., wastewater treatment plants (WWTP), industrial area (ID), residential area (RA), aquaculture area (QA), estuary (EST)) around the Hainan Island, we analyzed the MPs abundance and composition in water and sediment. Our findings revealed significant contributions of land-derived MPs, with an average abundance of 15,900 items/m3 in water and 3171 items/kg in sediment. Annually, approximately 61.6 trillion MPs were discharged into the South China Sea via rivers from Hainan Island, highlighting its role as a major land-derived source of MPs pollution in this critical marine ecosystem. Risk assessments indicated the H and PLI level of Hainan Island as II and I, respectively, with H-water level highest in WWTP and EST as III and H-sediment level highest in WWTP, RD and QA as II, and this indicated the critical function of WWTP to control the release of land-derived MPs and reduce the environmental risks. Correlation analysis underscored the influence of natural factors (currents, tides, waves, and drifts), socio-economic factors (population density, regional area, and agricultural output), and anthropogenic activity (tourism development) on coastal MPs pollution. On the basis of existing timely MPs prevention and control measures in Hainan province, such as intercepting the MPs via WWTP and prohibiting the direct discharge of aquaculture wastewater to the surrounding sea, this study re-underscored the urgency of MPs management on the protection of the South China Sea's eco-environmental quality in view of the pivotal role of Hainan Island on the isolated geographic position and the South China Sea's ecological health. Overall, this study offered scientific insights to support source-oriented strategies for coastal MPs pollution control by providing fundamental data for predicting land-derived MPs contributions on an island-scale.
以往有关微塑料（MPs）分布的研究主要集中在特定区域内的水体，而对直接排入孤岛周边功能区的微塑料的贡献研究则很少。本研究针对这一空白，调查了直接排入海南岛邻近海岸的水体和沉积物中微塑料的发生和分布情况，海南岛是中国南海的一个地理隔离和生态敏感地区。基于对海南岛周边 40 个典型排污口（隶属于五个功能区，即污水处理厂（WWTP）、工业区（ID）、居民区（RA）、水产养殖区（QA）、河口（EST））的采样，我们分析了水和沉积物中 MPs 的丰度和组成。研究结果表明，陆源 MPs 在水体中的平均丰度为 15,900 个/立方米，在沉积物中的平均丰度为 3,171 个/千克。每年约有 61.6 万亿 MPs 通过海南岛的河流排入南海，突出表明海南岛是这一重要海洋生态系统的主要陆源 MPs 污染源。风险评估表明，海南岛的 H 和 PLI 水平分别为Ⅱ级和Ⅰ级，其中污水处理厂和EST 的 H 水水平最高，为Ⅲ级；污水处理厂、RD 和 QA 的 H 泥沙水平最高，为Ⅱ级，这表明污水处理厂在控制陆源 MPs 排放和降低环境风险方面发挥着关键作用。相关性分析强调了自然因素（海流、潮汐、波浪和漂移）、社会经济因素（人口密度、区域面积和农业产出）和人为活动（旅游开发）对沿海 MPs 污染的影响。本研究在海南省现有及时采取微塑料防控措施（如通过污水处理厂拦截微塑料、禁止养殖废水直接排放到周边海域等）的基础上，针对海南岛孤立的地理位置和南海生态健康的关键作用，再次强调了微塑料治理对保护南海生态环境质量的紧迫性。总之，本研究为预测陆源 MPs 在岛屿尺度上的贡献提供了基础数据，为以源头为导向的沿海 MPs 污染控制策略提供了科学依据。
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Pub Date : 2025-02-13DOI: 10.1016/j.watres.2025.123297
Elizabeth F. Vicario, Ebenezer F. Amankwaa, Kebreab Ghebremichael, James R. Mihelcic
The world is not on track to attain universal access to safely managed drinking water by 2030, and urban water utilities in the global South struggle to keep up with rising demand. Non-revenue water losses are high for these utilities, but little is known about the causes of commercial losses, specifically theft. This study examines cause-effect relationships between utility decision making and water theft in informal settlements, where household connections are uncommon. A collaborative systems thinking approach was used to map and analyze these relationships within a causal loop diagram, which was created through direct involvement and/or data collection from over 100 stakeholders in Accra, Ghana. Three archetypal patterns influencing non-revenue water loss are revealed (Limits to Growth, Fixes that Backfire, and Success to the Successful), which explain how theft is propagated in an environment of undervalued water, minimal law enforcement, and low expectations of infrastructure and service quality. The utility's decision to reduce piped water supply to the settlement –an effort to combat non-revenue water loss – eventually leads to the domination of theft throughout the system, as legally operating vendors struggle to remain viable and continue paying utility bills. Recommendations include shifting system goals and creating two structural changes: 1) connecting legal vendor sales to utility income from the community, which would be inherent in a typical metered system, and 2) connecting utility income from the community to locally available funds for infrastructure investment. These changes, implemented through a cooperative agreement between the utility and informal vendors, would improve piped water service, sustain legal vending businesses, and lower non-revenue water losses without the capital costs of metered connections.
{"title":"How do water utilities’ decisions perpetuate theft in informal settlements? Collaborative systems analysis in Accra, Ghana","authors":"Elizabeth F. Vicario, Ebenezer F. Amankwaa, Kebreab Ghebremichael, James R. Mihelcic","doi":"10.1016/j.watres.2025.123297","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123297","url":null,"abstract":"The world is not on track to attain universal access to safely managed drinking water by 2030, and urban water utilities in the global South struggle to keep up with rising demand. Non-revenue water losses are high for these utilities, but little is known about the causes of commercial losses, specifically theft. This study examines cause-effect relationships between utility decision making and water theft in informal settlements, where household connections are uncommon. A collaborative systems thinking approach was used to map and analyze these relationships within a causal loop diagram, which was created through direct involvement and/or data collection from over 100 stakeholders in Accra, Ghana. Three archetypal patterns influencing non-revenue water loss are revealed (Limits to Growth, Fixes that Backfire, and Success to the Successful), which explain how theft is propagated in an environment of undervalued water, minimal law enforcement, and low expectations of infrastructure and service quality. The utility's decision to reduce piped water supply to the settlement –an effort to combat non-revenue water loss – eventually leads to the domination of theft throughout the system, as legally operating vendors struggle to remain viable and continue paying utility bills. Recommendations include shifting system goals and creating two structural changes: 1) connecting <em>legal vendor sales</em> to utility income from the community, which would be inherent in a typical metered system, and 2) connecting <em>utility income from the community</em> to locally available funds for infrastructure investment. These changes, implemented through a cooperative agreement between the utility and informal vendors, would improve piped water service, sustain legal vending businesses, and lower non-revenue water losses without the capital costs of metered connections.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"63 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143401758","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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