Water Research最新文献

{"title":"Methylsiloxanes in drinking water treatment plants: Occurrence, removal efficiencies and exposure risks across multiple stages of treatment process development","authors":"Yimeng Zhang ,&nbsp;Zhenyang Yu ,&nbsp;Jing Yang ,&nbsp;Ge Yin ,&nbsp;Yanbin Zhao ,&nbsp;G․Daniel Sheng ,&nbsp;Daqiang Yin","doi":"10.1016/j.watres.2025.124314","DOIUrl":"10.1016/j.watres.2025.124314","url":null,"abstract":"<div><div>Methylsiloxanes (MSs) are recognized as emerging pollutants and have been widely detected in surface waters that serve as drinking water sources. However, their removal efficiencies through various processes in drinking water treatment plants (DWTPs) remain poorly understood. The present study determined 17 MSs including 8 cyclic MSs (CMSs), 7 linear MSs (LMSs) and two hydride-terminated MSs (HDMSs) in 8 DWTPs which represented 4 typical treatment processes. In source water samples, 16 MSs were frequently detected, and the highest concentrations were observed in river network waters with the lowest ones in reservoir-derived waters. In the samples from DWTPs, the average total concentrations ranged from 34.2 to 147 ng/L for CMSs, 1.55 to 42.7 ng/L for LMSs and 14.1 to 133 ng/L for HDMSs, respectively. In each DWTP type, the total concentrations followed an order of CMSs &gt; HDMSs &gt; LMSs. The MSs can’t be completely removed by the DWTPs, with overall removal efficiencies ranging from 23.1 %∼63.7 % for CMSs, -58.9 %∼27.4 % for LMSs and 37.6 %∼87.2 % for HDMSs, respectively. In conventional DWTPs, disinfection functioned as the primary removal mechanism for MSs. In DWTPs with ozonation-biological activated carbon (O₃-BAC), both oxidation by O₃ and the disinfection contributed to the efficient removal. In DWTPs with pre-ozonation (or pre-chlorination), the O₃-BAC remained the key effective treatment step, while the disinfection showed negative contribution to the removal. The DWTPs with the artificial wetland or biological pretreatment with advanced processes including O₃-BAC, ultrafiltration (UF) and nanofiltration (NF) showed the highest removal efficiencies. The total average daily doses (ADDs) were below the corresponding chronic reference dose (RfD) values, suggesting low health risks. Further investigations on both toxicities and fates of these MSs are still necessary to strengthen health protection strategies.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"287 ","pages":"Article 124314"},"PeriodicalIF":12.4,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144715729","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}

{"title":"Extreme precipitation amplified the cumulative effects of DOM availability on organic-sourced DIC in the Yangtze River","authors":"Chu Zhao ,&nbsp;Guangrui Yang ,&nbsp;Lize Meng ,&nbsp;Heran Chen ,&nbsp;Shuaidong Li ,&nbsp;Farong Chen ,&nbsp;Zihao Bian ,&nbsp;Jiaming Chen ,&nbsp;Jian Zhou ,&nbsp;Qihao Jiang ,&nbsp;Tao Huang ,&nbsp;Hao Yang ,&nbsp;Changchun Huang","doi":"10.1016/j.watres.2025.124312","DOIUrl":"10.1016/j.watres.2025.124312","url":null,"abstract":"<div><div>Frequent extreme climate events are restructuring riverine carbon cycles dominated by dissolved inorganic carbon (DIC). However, the variability of dissolved organic matter (DOM) induced by rainstorm and its linkage to riverine DIC dynamics remain unclear, limiting an in-depth understanding of carbon transport and fate across the river-ocean continuum. This study employed Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) coupled with stable carbon and water isotope tracing techniques to investigate DOM-DIC interactions in the Yangtze River. Results demonstrated that organic matter constituted a major DIC source, contributing 13.52 ± 1.66% and 23.15 ± 3.27% of total DIC during normal (May) and rainstorm (September) periods in 2021, respectively. Extreme precipitation events (&gt;150 mm·day^-1) elevated dissolved organic carbon (DOC) concentration and the biological transformation index (<em>I</em>_bio) of DOM, while reducing molecular mass and double-bond equivalents (DBE) compared to the normal condition. During the rainstorm period, DOC concentration and <em>I</em>_bio values progressively declined downstream with increasing distance from the precipitation core, while molecular mass and DBE increased, contrasting with the spatially homogeneous DOM distribution characteristic of the normal period. Rainstorm enhanced terrestrial organic matter inputs, increasing DOC concentration and enriching low-molecular-weight, highly saturated CHO and CHON compounds. These synergistic effects accelerated DOM biodegradation to organic-sourced DIC (DICoc). Structural equation modeling further confirmed that extreme precipitation primarily promoted DICoc production through stimulated DOM biodegradation rather than photochemical oxidation. Storm events mobilized protein-like compounds from residential wastewater, while elevated water temperatures and nutrient levels collectively enhanced DOM biodegradability. Conversely, rainstorm-induced turbidity plumes suppressed photodegradation of terrestrial aromatic humic substances. Our findings highlight that precipitation-driven DOM loading and molecular transformations significantly accelerate biogeochemical carbon cycling.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"287 ","pages":"Article 124312"},"PeriodicalIF":12.4,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144715728","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}

{"title":"Public goods-mediated bacterial interplay in aquatic ecosystems","authors":"Yerim Park ,&nbsp;Wonjae Kim ,&nbsp;Jihye Bae ,&nbsp;Woojun Park","doi":"10.1016/j.watres.2025.124310","DOIUrl":"10.1016/j.watres.2025.124310","url":null,"abstract":"<div><div>Microbial public goods, including siderophores, heme, and catalases, underpin cooperative interactions in aquatic environments. These extracellular compounds enable resource acquisition, stress mitigation, and metabolic cross-feeding, helping aquatic microbial communities cope with environmental stress and sustain their ecological roles. Because public goods are freely available to surrounding cells, their production involves balancing individual cost and community benefit, generating conflict between cooperation and cheating. External cues such as nutrient limitation, salinity shifts, and oxidative stress modulate the production and utilization of microbial public goods. Aquatic systems are physically homogeneous and dilute, fostering metabolic interdependence by increasing reliance on externally available compounds and shaping cooperation through dependency rather than autonomy. In parallel, genomic traits such as gene loss or streamlining in oligotrophic aquatic taxa further reinforce this cooperative mode. Many aquatic microbes have lost the full genetic capacity to synthesize essential metabolites, including vitamins, siderophores, and antioxidants, making them dependent on extracellular metabolites provided by other community members. In such water environments, the production and accessibility of public goods become central to survival, fostering cross-feeding and collective stress responses. This shared resource dependence reinforces cooperation and drives community organization and functional interdependence, underscoring the ecological and evolutionary importance of public goods in shaping aquatic microbial ecosystems.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"287 ","pages":"Article 124310"},"PeriodicalIF":12.4,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144719419","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}

{"title":"Contrasting seasonal variations in riverine nitrogen and phosphorus concentrations in China: implications for N/P imbalances","authors":"Honghao Liu ,&nbsp;Lin Gao ,&nbsp;Ze Yuan ,&nbsp;Ting Ma","doi":"10.1016/j.watres.2025.124317","DOIUrl":"10.1016/j.watres.2025.124317","url":null,"abstract":"<div><div>Rivers are critical conduits of nitrogen (N) and phosphorus (P), essential nutrients that regulate the productivity and resilience of freshwater ecosystems through seasonal fluctuations. However, comprehensive assessments of the seasonal dynamics of N, P, and their stoichiometric ratios in river ecosystems, as along with the underlying natural and anthropogenic drivers of the magnitude of these seasonal variations, remain scarce. In this study, we conduct an investigation of seasonal variations in total nitrogen (TN), total phosphorus (TP) concentrations, and their stoichiometric ratios across 150 medium-sized river basins in China. Our findings reveal starkly contrasting seasonal trends: TP concentration peaks in spring and summer, while TN concentration reaches maximum levels in winter, resulting pronounced intra-annual fluctuations in TN:TP ratios. These divergent dynamics are modulated by a complex interplay of hydrological variability, temporal autocorrelation in nutrient concentrations, and temperature-driven processes. Seasonal fluctuation in the TN:TP ratio leads to spatiotemporal variability in nutrient constraints. Seasonal differences in water temperature and the magnitude of TN variability explain 22 % and 14 % of this variation, respectively, while climatic factors and anthropogenic influences account for 15 % and 13 %. Phosphorus-limitation dominates most river systems year-round, but seasonal shifts toward N-P co-limitation occur in southern basins during warmer months. Water temperature emerged as a primary driver, influencing the magnitude of seasonal variability in nutrient concentrations, with hydrological discharge and human activities providing additional influence. The seasonal variability of TN and TP is substantially greater in northern basins than in southern basins, and this regional heterogeneity is closely associated with differences in climate, land use, and anthropogenic inputs. These findings underscore the need for regionally adaptive, season-specific nutrient management strategies to address growing N/P imbalances exacerbated by climate change and anthropogenic impacts.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"287 ","pages":"Article 124317"},"PeriodicalIF":12.4,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144719462","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}

{"title":"Thioarsenate immobilization by ferrous sulfides for geogenic contaminated groundwater rehabilitation: Mechanisms and kinetic constraints","authors":"Xiaona Li ,&nbsp;Chaoyu Zhang ,&nbsp;Kunfu Pi ,&nbsp;Xianjun Xie ,&nbsp;Yuxia Li ,&nbsp;Yanxin Wang","doi":"10.1016/j.watres.2025.124306","DOIUrl":"10.1016/j.watres.2025.124306","url":null,"abstract":"<div><div>Thioarsenic prevails in sulfidic environments and exhibits higher mobility than arsenate (As(V)) and arsenite (As(III)), posing sustained challenge to the effectiveness of geogenic As-contaminated groundwater rehabilitation. Ferrous sulfide (FeS) minerals are proposed scavengers of monothioarsenate (MTA) in sulfidic groundwater, but the underlying mechanisms and kinetic processes remain elusive. This research presents new key evidence that MTA retention by FeS is constrained by a multi-reaction process: initial rapid adsorption, and subsequently slow binding to kinetics-controlled sites and irreversibly-retained phase. Polysulfides critically strengthen MTA retention by transforming MTA to less mobile As(V) and facilitating arsenopyrite (FeAsS) production. Simulating MTA isothermal adsorption edge with modified dual mode model confirms that MTA removal involves surface chemisorption and mineral transformation. While MTA removal rates were higher under weakly acidic conditions (pH 6–7), more stable FeAsS formed under alkaline conditions (pH 8–9) can strengthen As immobilization against re-desorption. Further column experiments to mimic in-situ FeS coating for MTA immobilization indicate that the simultaneously formed FeS, which induces MTA co-precipitation and production of pyrite and FeAsS, exhibited greater retention capacity than the pre-loaded FeS. These findings manifest important implications in scheming modes of in-situ Fe coating and transformation for managed rehabilitation of As-contaminated groundwater.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"287 ","pages":"Article 124306"},"PeriodicalIF":12.4,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144712215","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}

{"title":"Moisture-driven microbial regime shifts mediate nutrient dynamics in reservoir riparian zones","authors":"Yi Li ,&nbsp;Xiaodan Liang ,&nbsp;Nan Yang ,&nbsp;Li Lin ,&nbsp;Tian Gao","doi":"10.1016/j.watres.2025.124309","DOIUrl":"10.1016/j.watres.2025.124309","url":null,"abstract":"<div><div>Reservoir-regulated hydrological regimes generate riparian ecotones through cyclic inundation and exposure, establishing transient biogeochemical hotspots that modulate elemental fluxes across land-water continua. Although functionally specialized microbiomes drive critical nutrient transformations within these ecotones, their resilience thresholds confront escalating pressures from hydrological extremes, which may induce catastrophic state transitions disrupting biogeochemical cycles. Despite their importance, the underlying mechanisms regulating microbial community dynamics, state transitions, and their ecological consequences under fluctuating hydrological regimes remain poorly understood. This study employs alternative stable state theory to investigate hysteretic responses of microbial communities along moisture gradients, coupled with mechanistic evaluation of their mediation on nutrient cycling. Our findings reveal bistability in microbial assemblages, demonstrating regime shifts with hysteresis under moisture stress. Through potential landscape analysis and soil multifunctionality assessment, we identified two distinct ecological states: under low moisture conditions (&lt;15 %), microbial communities maintain structural stability with slow nitrogen cycling and carbon metabolism, dominated by drought-adapted taxa (e.g., Actinobacteriota); while under high moisture conditions (&gt;30 %), they transition to moisture-dependent states characterized by Desulfobacterota and Bacteroidota dominance, exhibiting enhanced carbon metabolism and denitrification capacity. Moisture stress significantly reduced α-diversity while increasing dispersal limitation and network complexity, suggesting enhanced niche differentiation under arid conditions. These contrasting states fulfill complementary ecosystem functions: the low-moisture state preserves soil carbon and nitrogen, whereas the high-moisture state achieves nitrate removal, effectively mitigating eutrophication risks. By mapping microbial collapse and recovery trajectories along moisture gradients, this study provides a mechanistic understanding of riparian ecosystem resilience and offers actionable insights for the predictive management of reservoir riparian zones.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"287 ","pages":"Article 124309"},"PeriodicalIF":12.4,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144715731","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}

{"title":"Natural organic matter-enhanced atmospheric Hg(0) uptake involves thiol-induced unusual electron transfer from Hg to carboxyl moiety","authors":"Xiaoyan Zhang ,&nbsp;Yingying Guo ,&nbsp;Wang Zheng ,&nbsp;Jun Liu ,&nbsp;Yanbin Li ,&nbsp;Yanwei Liu ,&nbsp;Jianbo Shi ,&nbsp;Ligang Hu ,&nbsp;Xiaoshan Zhang ,&nbsp;Yongguang Yin ,&nbsp;Yong Cai ,&nbsp;Guibin Jiang","doi":"10.1016/j.watres.2025.124311","DOIUrl":"10.1016/j.watres.2025.124311","url":null,"abstract":"<div><div>Natural organic matter (NOM)-mediated non-photochemical oxidation of elemental mercury (Hg(0)), as an important process controlling Hg cycle, is still not well understood, particularly with respect to its electron transfer and environmental significance relevant to Hg(0) uptake by seawater. Here, we studied the uptake of atmospheric Hg(0) and its subsequent aqueous non-photochemical oxidation in seawater in the presence of NOM, by using extracellular polymeric substances and thiol compounds as NOM models. We observed NOM enhanced Hg(0) partition into seawater and its aqueous oxidation. Our results demonstrated that NOM mediated Hg(0) oxidation through a non-radical but thiol complexation-induced pathway, where electrons were transferred from Hg(0) to carboxyl moiety, resulting in the reduction of carboxyl accompanying Hg(0) oxidation. Thiol complexation with Hg(II) decreases the reduction potential of Hg(0) oxidation (Hg(0)→Hg(II)+2e⁻) and therefore carboxyl group can act as an electron acceptor to be reduced to aldehyde/alcohol, as revealed by thermodynamic calculation and mass spectrometry analysis based on thiol models. This unusual Hg(0) oxidation pathway accompanied by the reduction of carboxyl to alcohol was also validated for NOM using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis. This NOM-mediated Hg(0) oxidation provides important environmental implications on the atmospheric Hg(0) deposition over environmental surfaces.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"287 ","pages":"Article 124311"},"PeriodicalIF":12.4,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144715733","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}

{"title":"Viral-community-induced antibiotic resistance gene regulation throughout the process of sewage sludge composting and its subsequent application to a phosphate mining wasteland: A three-year, large-scale field study","authors":"Xingkun Xu, Yufeng Jia, Yuecen Dong, Mingdong Yu, Mingyue Xu, Chi Zhang, Ping Zhou, Bao Yu, Wenjing Lu, Jianguo Liu","doi":"10.1016/j.watres.2025.124308","DOIUrl":"https://doi.org/10.1016/j.watres.2025.124308","url":null,"abstract":"The application of sewage sludge compost to phosphate mining wastelands improves soil quality, and provides a viable solution for sludge disposal. However, attention must be paid to antibiotic resistance genes (ARGs) in sewage sludge. Based on a large-scale field study, we comprehensively profiled the antibiotic resistome throughout the process of sewage sludge composting and its subsequent application to a phosphate mining wasteland. The trend of the ARG abundance in the phosphate mining wasteland after applying sewage sludge compost was consistent with the priming effect. The total ARG abundance in the phosphate mining wasteland increased by 38.3% in the 1st year of soil reclamation but significantly decreased in the 3rd year. Nevertheless, multi-resistant plasmids persisted in the reclaimed soil. Our findings also support the contribution of viral communities to ARG regulation in phosphate mining wastelands, and the virus–ARG interactions were lifestyle- and host-dependent. Moreover, there was an overlap between the ARG and phage hosts, and phylogenetic coherence of ARG hosts against bacitracin, sulfonamide, macrolide-lincosamide-streptogramin, polymyxin, and rifamycin was observed.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"24 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144712263","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}

{"title":"Modeling interactions between the adsorption of dissolved organic carbon and biological activity on granular activated carbon","authors":"Tobias Kaiser ,&nbsp;Cristian Picioreanu ,&nbsp;Susanne Lackner","doi":"10.1016/j.watres.2025.124304","DOIUrl":"10.1016/j.watres.2025.124304","url":null,"abstract":"<div><div>Several studies observed that biological removal of organic substances in biofilters during advanced wastewater treatment depends on the type of filter bed material. Even after long operation, granular activated carbon (GAC) filters showed superior removal of organic substances compared to biofilters with non-adsorbing filter bed materials, suggesting that enhanced biological activity may be the main driver for this observation. In this study, a one-dimensional (1D) continuum multispecies biofilm model coupled with multisolute adsorption of dissolved organic carbon (DOC) was developed to simulate a single biologically active GAC grain. Simulations with an impermeable, non-adsorbing grain were carried out for comparison. The results of this conceptual study demonstrated that adsorptive removal of biodegradable DOC did not influence biofilm development or its final microbial community composition (differences in volume fractions of active biofilm components were &lt; 1.5 % with a total particulate volume fraction of 25 % in the biofilm). Even desorption of previously adsorbed biodegradable DOC, triggered by corresponding concentration gradients between the grain and the biofilm, had no significant effect, although up to 20 % of it was released in the simulated scenarios. This desorption was driven either by increasing biological activity during biofilm development or by sudden concentration changes in the bulk and was also influenced by the biofilm thickness. Overall, the biofilm thickness proved to be a decisive influencing factor. With increasing biofilm thickness, the models predicted increased biological activity and a more diverse microbial community composition, independent of adsorption or desorption processes. The simulation results therefore suggest that the increased biological activity observed in GAC systems does not result from adsorptive interactions between the GAC and biodegradable DOC. Other influencing factors such as protection against detachment, which leads to thicker biofilms, might play a more important role.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"287 ","pages":"Article 124304"},"PeriodicalIF":12.4,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144712265","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}

{"title":"In situ-generated palladium nanoparticles promoted co-reduction of bromate and nitrate in hydrogenotrophic biofilms","authors":"Chengyang Wu, Guirong Liang, Siqing Xia, Jingzhou Zhou, Eric Lichtfouse, Xiang Cai, Suyun Xu, Hongbo Liu","doi":"10.1016/j.watres.2025.124303","DOIUrl":"https://doi.org/10.1016/j.watres.2025.124303","url":null,"abstract":"Bromate, a carcinogenic disinfection byproduct, threatens water safety due to its persistence and health risks. Although microbial reduction of bromate is a sustainable remediation approach, its efficiency is often hampered by the common co-contamination of nitrate. We addressed this issue by generating palladium nanoparticles (PdNPs) in situ within the biofilm matrix of a membrane biofilm reactor (MBfR), creating a Pd-MBfR. Co-reduction of bromate and nitrate by the Pd-MBfR was investigated in terms of bromate removal, reduction kinetics, and microbial functions. To evaluate the impact of catalytic hydrogenation, a non-palladized MBfR was operated in parallel. Continuous operation over 125 days demonstrated that the Pd-MBfR reduced bromate concentration (4 mg·L^-1) up to 70%, versus 30% for the conventional MBfR under competitive nitrate or nitrite conditions. Kinetic modeling revealed that extracellular Pd-catalyzed bromate reduction diverted approximately18% of bromate flux from intracellular NADH-dependent pathways, while biogenic PdNPs rapidly scavenged nitrite via catalytic hydrogenation, diverting 39% of intracellular electron flux from denitrification to extracellular catalytic reduction. Under nitrate stress, biofilms in the Pd-MBfR maintained syntrophic interactions between bromate-reducing bacteria <em>Dechloromonas</em> and homoacetogens <em>Acetobacterium</em>, whereas the conventional MBfR favored autotrophic denitrifiers <em>Hydrogenophaga</em> and <em>Rhodoblastus</em> that prioritized nitrate reduction. Functional-gene profiling confirms that the intracellular electron flow from hydrogen to NADH-dependent denitrification reductases was displaced by extracellular Pd-catalyzed hydrogenation. This diversion of electron flow enhanced bromate reduction in biofilms coupled with PdNPs by minimizing competition for intracellular NADH.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"22 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144712267","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}