Madeleine Siegel, Joe Huyett, Maxwell Pisciotta, Peter Psarras, Jennifer Wilcox, Todd Bandhauer
Direct air capture (DAC) technologies that remove CO2 directly from the atmosphere are needed to meet international goals of limiting the atmospheric temperature increase before 2100. Operating costs, including the cost of energy inputs, currently limit the rapid deployment of DAC systems. An abundance of untapped and abandoned geothermal resources provides an opportunity to utilize this thermal energy beneath the earth’s surface to reduce the financial and energy costs of DAC. In this study, thermodynamic models of applicable renewable energy scenarios for fulfilling heating and electrical requirements of DAC were analyzed using ASPEN Plus. Individual components were optimized within the geothermal–DAC-coupled systems to quantify specific costs of implementation. The results were integrated into a technoeconomic analysis to provide a holistic perspective to optimize DAC-coupled renewable energy systems. The analysis found that scenarios using geothermal heat for CO2 desorption with either solar and batteries or an organic Rankine cycle for electric loads could lower the cost of DAC systems compared to a solar-with-batteries baseline. The levelized cost of energy for CO2 removal (LCOECR) for DAC was reduced from $175/t-CO2 removed to as low as $66/t-CO2 removed, guiding large-scale deployment of DAC and supporting decision-making in the future.
{"title":"Evaluating Thermal Efficiency and Economic Impacts in Supplying Energy Demands for Direct Air Capture","authors":"Madeleine Siegel, Joe Huyett, Maxwell Pisciotta, Peter Psarras, Jennifer Wilcox, Todd Bandhauer","doi":"10.1021/acs.est.5c12850","DOIUrl":"https://doi.org/10.1021/acs.est.5c12850","url":null,"abstract":"Direct air capture (DAC) technologies that remove CO<sub>2</sub> directly from the atmosphere are needed to meet international goals of limiting the atmospheric temperature increase before 2100. Operating costs, including the cost of energy inputs, currently limit the rapid deployment of DAC systems. An abundance of untapped and abandoned geothermal resources provides an opportunity to utilize this thermal energy beneath the earth’s surface to reduce the financial and energy costs of DAC. In this study, thermodynamic models of applicable renewable energy scenarios for fulfilling heating and electrical requirements of DAC were analyzed using ASPEN Plus. Individual components were optimized within the geothermal–DAC-coupled systems to quantify specific costs of implementation. The results were integrated into a technoeconomic analysis to provide a holistic perspective to optimize DAC-coupled renewable energy systems. The analysis found that scenarios using geothermal heat for CO<sub>2</sub> desorption with either solar and batteries or an organic Rankine cycle for electric loads could lower the cost of DAC systems compared to a solar-with-batteries baseline. The levelized cost of energy for CO<sub>2</sub> removal (LCOE<sub>CR</sub>) for DAC was reduced from $175/t-CO<sub>2</sub> removed to as low as $66/t-CO<sub>2</sub> removed, guiding large-scale deployment of DAC and supporting decision-making in the future.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"1 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711171","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}
Estuaries are dynamic processing hubs for dissolved organic matter (DOM), and bacteria play key roles in DOM transformation. However, the processes and drivers of estuarine bacteria-mediated DOM transformation remain poorly understood. We investigated the DOM composition, bacterial communities, and environmental factors across four geographically distinct estuaries: Jiaozhou Bay (JZB), Xiamen Bay (XMB), Chesapeake Bay (CB), and Mission-Aransas Estuary (MAE). During the sampling period, JZB and XMB were enriched in autochthonous DOM, while CB and MAE were dominated by terrestrial DOM. Bacterial diversity was significantly greater in JZB and XMB than in CB and MAE. Co-occurrence networks showed that Proteobacteria (41.4% ± 9.8%) were extensively involved in estuarine DOM metabolism; bacterial communities exhibited a metabolic preference for carboxyl-rich alicyclic molecules (71.7% ± 7.1%) in all estuaries, and more complex communities had greater capacity to degrade recalcitrant DOM. Structural equation modeling further indicated that bacterial-mediated DOM transformation in all estuaries was regulated by similar environmental factors (temperature and dissolved inorganic nitrogen). Warming and nitrogen limitation could reduce bacterial diversity and promote the accumulation of recalcitrant DOM. Overall, this study explored estuarine bacteria-mediated DOM transformation at the molecular level and identified common environmental drivers, providing deeper insight into the fate of estuarine DOM.
{"title":"Similar Drivers of Bacteria-Mediated Dissolved Organic Matter Transformation across Geographically Distinct Estuaries.","authors":"Zhenli Guo,Michael Gonsior,Xiaotian Liu,Feng Chen,Xiangbin Ran,Hualong Hong,Nianzhi Jiao,Xilin Xiao","doi":"10.1021/acs.est.5c14402","DOIUrl":"https://doi.org/10.1021/acs.est.5c14402","url":null,"abstract":"Estuaries are dynamic processing hubs for dissolved organic matter (DOM), and bacteria play key roles in DOM transformation. However, the processes and drivers of estuarine bacteria-mediated DOM transformation remain poorly understood. We investigated the DOM composition, bacterial communities, and environmental factors across four geographically distinct estuaries: Jiaozhou Bay (JZB), Xiamen Bay (XMB), Chesapeake Bay (CB), and Mission-Aransas Estuary (MAE). During the sampling period, JZB and XMB were enriched in autochthonous DOM, while CB and MAE were dominated by terrestrial DOM. Bacterial diversity was significantly greater in JZB and XMB than in CB and MAE. Co-occurrence networks showed that Proteobacteria (41.4% ± 9.8%) were extensively involved in estuarine DOM metabolism; bacterial communities exhibited a metabolic preference for carboxyl-rich alicyclic molecules (71.7% ± 7.1%) in all estuaries, and more complex communities had greater capacity to degrade recalcitrant DOM. Structural equation modeling further indicated that bacterial-mediated DOM transformation in all estuaries was regulated by similar environmental factors (temperature and dissolved inorganic nitrogen). Warming and nitrogen limitation could reduce bacterial diversity and promote the accumulation of recalcitrant DOM. Overall, this study explored estuarine bacteria-mediated DOM transformation at the molecular level and identified common environmental drivers, providing deeper insight into the fate of estuarine DOM.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"46 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711155","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}
Bingling Yuan,Lei Xing,Zhoulan Huang,Guoxiong Zhan,Yuchen Li,Zhen Chen,Lidong Wang,Junhua Li
Chemical absorption with biphasic solvents is considered a promising and energy-efficient route for CO2 capture. However, achieving efficient dynamic phase splitting remains a significant challenge, primarily due to the unclear intrinsic relationship between amine species and their separation behavior. To address this issue, specific amino groups were controlled to develop biphasic solvents by incorporating various amines, the phase-splitting behavior of which was thoroughly investigated at the macro, micro, and molecular scales. It is found that the chemical structure of the amine is the dominant factor in regulating the phase separation behavior of the two-phase solvent, and the influence of the molar concentration is only a minor fine-tuning effect. The formation of immiscible clusters was reconstructed through molecular simulation, revealing the dominant role of hydrogen bonding between solvent species. Influenced by gravity, buoyancy, viscous forces, and surface tension, the immiscible clusters underwent sedimentation, coalescence, and breakup before dissolving into bulk phases with similar properties, ultimately forming two phases with well-defined boundaries. The phase-splitting kinetics were established based on the visualized records of cluster motion and the time-space profile of the CO2/H2O content. Overall, this work clarifies the complex influence of molecular polarity and cluster motion on various stages of phase-splitting behavior, elucidating a valuable perspective for the design and application of biphasic solvents.
{"title":"Multiscale Exploration of Dynamic Phase-Splitting Behavior for Biphasic Solvent in CO2 Capture.","authors":"Bingling Yuan,Lei Xing,Zhoulan Huang,Guoxiong Zhan,Yuchen Li,Zhen Chen,Lidong Wang,Junhua Li","doi":"10.1021/acs.est.5c05951","DOIUrl":"https://doi.org/10.1021/acs.est.5c05951","url":null,"abstract":"Chemical absorption with biphasic solvents is considered a promising and energy-efficient route for CO2 capture. However, achieving efficient dynamic phase splitting remains a significant challenge, primarily due to the unclear intrinsic relationship between amine species and their separation behavior. To address this issue, specific amino groups were controlled to develop biphasic solvents by incorporating various amines, the phase-splitting behavior of which was thoroughly investigated at the macro, micro, and molecular scales. It is found that the chemical structure of the amine is the dominant factor in regulating the phase separation behavior of the two-phase solvent, and the influence of the molar concentration is only a minor fine-tuning effect. The formation of immiscible clusters was reconstructed through molecular simulation, revealing the dominant role of hydrogen bonding between solvent species. Influenced by gravity, buoyancy, viscous forces, and surface tension, the immiscible clusters underwent sedimentation, coalescence, and breakup before dissolving into bulk phases with similar properties, ultimately forming two phases with well-defined boundaries. The phase-splitting kinetics were established based on the visualized records of cluster motion and the time-space profile of the CO2/H2O content. Overall, this work clarifies the complex influence of molecular polarity and cluster motion on various stages of phase-splitting behavior, elucidating a valuable perspective for the design and application of biphasic solvents.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"31 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145710916","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}
Phosphodiesterase type V inhibitors (PDE-5is) are widely used for the treatment of erectile dysfunction, and global demand for these pharmaceuticals continues to grow. However, the circulation of unlicensed and counterfeit PDE-5is poses serious public health risks. This study employed solid-phase extraction coupled with LC–MS/MS to analyze 116 influent wastewater samples collected in Dalian, China, in order to assess the temporal and spatial trends in the community-level use of counterfeit PDE-5is. Among the three target compounds, neither tadalafil nor vardenafil was detected in any sample. Sildenafil, however, was found in 94.5% of the samples, with concentrations ranging from below the limit of quantification (LOQ) to 75.4 ng/L. Its major metabolite, desmethylsildenafil, was detected in concentrations ranging from < LOQ to 107 ng/L. Sildenafil consumption steadily increased between 2017 and 2022 (40.8 to 87.8 mg/d/1000 inh). Notably, the estimated consumption based on wastewater data far exceeded local prescription sales, which accounted for only approximately 20% of the total use, with counterfeit sildenafil use estimated to exceed 100 kg/year in Dalian. This discrepancy indicates that the majority of sildenafil is obtained through over-the-counter sales or illegal channels. For spatial analysis, wastewater treatment plants were classified according to the characteristics of the populations they served. Sildenafil consumption was substantially higher in urban areas (70.4 mg/d/1000 inh) than in rural areas (25.4 mg/d/1000 inh), indicating more widespread use of counterfeit products in urban populations. Subpopulation analysis further revealed that college students (38.5 mg/d/1000 inh) and island residents (28.6 mg/d/1000 inh) had lower levels of use compared to the general population (85.1 mg/d/1000 inh). These results highlight the potential of wastewater-based drug surveillance in tracking consumption trends of nonprescribed and counterfeit pharmaceuticals, offering robust evidence to inform regulatory efforts and improve public risk perception.
{"title":"Spatial and Temporal Tracking of Counterfeit Phosphodiesterase Type V Inhibitors Use Based on Wastewater Analysis","authors":"Xue-Ting Shao, Wei Pei, Yan-Ying Li, Dong-Qin Tan, Jing-Long Li, De-Gao Wang","doi":"10.1021/acs.est.5c10372","DOIUrl":"https://doi.org/10.1021/acs.est.5c10372","url":null,"abstract":"Phosphodiesterase type V inhibitors (PDE-5is) are widely used for the treatment of erectile dysfunction, and global demand for these pharmaceuticals continues to grow. However, the circulation of unlicensed and counterfeit PDE-5is poses serious public health risks. This study employed solid-phase extraction coupled with LC–MS/MS to analyze 116 influent wastewater samples collected in Dalian, China, in order to assess the temporal and spatial trends in the community-level use of counterfeit PDE-5is. Among the three target compounds, neither tadalafil nor vardenafil was detected in any sample. Sildenafil, however, was found in 94.5% of the samples, with concentrations ranging from below the limit of quantification (LOQ) to 75.4 ng/L. Its major metabolite, desmethylsildenafil, was detected in concentrations ranging from < LOQ to 107 ng/L. Sildenafil consumption steadily increased between 2017 and 2022 (40.8 to 87.8 mg/d/1000 inh). Notably, the estimated consumption based on wastewater data far exceeded local prescription sales, which accounted for only approximately 20% of the total use, with counterfeit sildenafil use estimated to exceed 100 kg/year in Dalian. This discrepancy indicates that the majority of sildenafil is obtained through over-the-counter sales or illegal channels. For spatial analysis, wastewater treatment plants were classified according to the characteristics of the populations they served. Sildenafil consumption was substantially higher in urban areas (70.4 mg/d/1000 inh) than in rural areas (25.4 mg/d/1000 inh), indicating more widespread use of counterfeit products in urban populations. Subpopulation analysis further revealed that college students (38.5 mg/d/1000 inh) and island residents (28.6 mg/d/1000 inh) had lower levels of use compared to the general population (85.1 mg/d/1000 inh). These results highlight the potential of wastewater-based drug surveillance in tracking consumption trends of nonprescribed and counterfeit pharmaceuticals, offering robust evidence to inform regulatory efforts and improve public risk perception.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"142 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711470","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}
Xiaoxiao Zhang,Weijian Xu,Wenjing Tian,Eakalak Khan,Daniel C W Tsang
Dissolved black carbon (DBC) from nitrogen-rich feedstock-derived pyrogenic carbon may influence aquatic photochemistry and byproduct formation due to its electron-donating capacity (EDC). Yet, the molecular drivers of EDC remain unclear. Here, we developed an integrated analytical framework to characterize DBC leached from nitrogen-rich biochar pyrolyzed at 350, 450, and 550 °C (DBC350, DBC450, and DBC550) under simulated intermittent rainfall over 30 days. Through two-dimensional correlation spectroscopy (2D-COS) and Fourier transform ion cyclotron resonance mass spectrometry, we analyzed sequential responses and synergistic relationships of thousands of individual DBC molecules with various functional groups. The EDC increased with leaching time, particularly in DBC350, coinciding with a shift toward lower m/z, more unsaturated, and aromatic compounds. Spearman's analysis showed that EDC-related molecules were predominantly nitrogen-bearing (61-76%), highly unsaturated, and low-oxygen. Our 2D-COS analysis on EDC-related molecules and functional groups identified (hetero)aromatic structures as key EDC contributors. Tandem mass spectrometry and X-ray photoelectron spectroscopy further confirmed the prevalence of carboxylic, pyrrolic, and/or amide groups. Extended (hetero)aromatic structures contributed to the higher EDC in DBC350 than in DBC450 and DBC550. Our study offers the first molecular and functional group-level insight into EDC-related DBC compositions, with implications for biochar-related and postwildfire water quality management.
{"title":"Molecular Drivers of Electron-Donating Capacity in Dissolved Black Carbon from Nitrogen-Rich Pyrogenic Carbon.","authors":"Xiaoxiao Zhang,Weijian Xu,Wenjing Tian,Eakalak Khan,Daniel C W Tsang","doi":"10.1021/acs.est.5c09050","DOIUrl":"https://doi.org/10.1021/acs.est.5c09050","url":null,"abstract":"Dissolved black carbon (DBC) from nitrogen-rich feedstock-derived pyrogenic carbon may influence aquatic photochemistry and byproduct formation due to its electron-donating capacity (EDC). Yet, the molecular drivers of EDC remain unclear. Here, we developed an integrated analytical framework to characterize DBC leached from nitrogen-rich biochar pyrolyzed at 350, 450, and 550 °C (DBC350, DBC450, and DBC550) under simulated intermittent rainfall over 30 days. Through two-dimensional correlation spectroscopy (2D-COS) and Fourier transform ion cyclotron resonance mass spectrometry, we analyzed sequential responses and synergistic relationships of thousands of individual DBC molecules with various functional groups. The EDC increased with leaching time, particularly in DBC350, coinciding with a shift toward lower m/z, more unsaturated, and aromatic compounds. Spearman's analysis showed that EDC-related molecules were predominantly nitrogen-bearing (61-76%), highly unsaturated, and low-oxygen. Our 2D-COS analysis on EDC-related molecules and functional groups identified (hetero)aromatic structures as key EDC contributors. Tandem mass spectrometry and X-ray photoelectron spectroscopy further confirmed the prevalence of carboxylic, pyrrolic, and/or amide groups. Extended (hetero)aromatic structures contributed to the higher EDC in DBC350 than in DBC450 and DBC550. Our study offers the first molecular and functional group-level insight into EDC-related DBC compositions, with implications for biochar-related and postwildfire water quality management.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"1 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711153","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}
Polyphenols represent an important component of soil organic matter (SOM) that widely originates from plants. Birnessite, a ubiquitous manganese (Mn)-oxide, effectively facilitates the oxidative decomposition and polymerization of polyphenols. However, the impact of pH and molecular structure of polyphenols on such processes, as well as the characterization of the degradation products, has not been fully elucidated. Therefore, we performed batch sorption experiments under environmentally relevant pH conditions to investigate the interactions between birnessite and two polyphenol isomers: catechol and hydroquinone. Results revealed that catechol was more effective in reducing Mn and dissolving Mn-oxide than hydroquinone, particularly under lower pH conditions. Correspondingly, a greater amount of carbon was lost from the aqueous system due to sorption and/or oxidative decomposition during catechol reactions than hydroquinone. Spectral data support the concomitant formation of polymers and aliphatic degradation products for both compounds studied. Moreover, lower pH conditions increased the degree of oxidation and proportion of low-molecular-weight species formed. The ortho positioning of hydroxyl groups in catechol facilitated more effective complexation and electron transfer to birnessite than the para configuration of hydroxyls in hydroquinone. This study provides valuable insights into the potential pathways of organo-mineral associations involving Mn-oxides and their role in (de)stabilizing SOM.
{"title":"Characterizing the Effect of pH and Molecular Structure on the Reactions of Catechol and Hydroquinone with Birnessite.","authors":"Benjamin Atkins,Subin Kalu,Hui Li","doi":"10.1021/acs.est.5c02143","DOIUrl":"https://doi.org/10.1021/acs.est.5c02143","url":null,"abstract":"Polyphenols represent an important component of soil organic matter (SOM) that widely originates from plants. Birnessite, a ubiquitous manganese (Mn)-oxide, effectively facilitates the oxidative decomposition and polymerization of polyphenols. However, the impact of pH and molecular structure of polyphenols on such processes, as well as the characterization of the degradation products, has not been fully elucidated. Therefore, we performed batch sorption experiments under environmentally relevant pH conditions to investigate the interactions between birnessite and two polyphenol isomers: catechol and hydroquinone. Results revealed that catechol was more effective in reducing Mn and dissolving Mn-oxide than hydroquinone, particularly under lower pH conditions. Correspondingly, a greater amount of carbon was lost from the aqueous system due to sorption and/or oxidative decomposition during catechol reactions than hydroquinone. Spectral data support the concomitant formation of polymers and aliphatic degradation products for both compounds studied. Moreover, lower pH conditions increased the degree of oxidation and proportion of low-molecular-weight species formed. The ortho positioning of hydroxyl groups in catechol facilitated more effective complexation and electron transfer to birnessite than the para configuration of hydroxyls in hydroquinone. This study provides valuable insights into the potential pathways of organo-mineral associations involving Mn-oxides and their role in (de)stabilizing SOM.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"35 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711154","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}
Yujie Fan, Weijian Zhang, Xiaopeng Ren, John C. Little, Ying Xu
Water-based paints, despite being marketed as environmentally friendly, emit various chemicals of emerging concern (CECs) that may pose health risks indoors. This study characterizes CEC emissions from water-based paints through systematic experiments and modeling. Four CECs, covering a broad range of volatility, were tested experimentally. Results showed distinct emission patterns for chemicals with varying volatility: high-volatility CECs, like diethylene glycol butyl ether, exhibited rapid peak-and-decay emissions, while low-volatility triethylene glycol bis(2-ethylhexanoate) showed persistent emissions over 100 days. A dynamic mass transfer model was developed and validated against experimental data. The partition coefficient between polymer particles and air (Kpa) and the diffusion coefficient within the polymer (Dp) were identified as the key parameters governing emissions. The model classified emissions of 20 common CECs into short (<10 days), medium (10–100 days), and long-term (>1000 days) profiles, highlighting prolonged exposure risks for low-volatility compounds. Substrate effects showed that permeable substrates reduced initial emissions of volatile CECs but had minimal impact on long-term release. The model was applied to a residential indoor scenario, demonstrating its utility for exposure assessment. These findings improve the understanding of CEC emissions from water-based paints and provide valuable insights for more accurate risk assessments and safer product design.
{"title":"Chemicals of Emerging Concern Emitted from Water-Based Paints: Experiments and Modeling","authors":"Yujie Fan, Weijian Zhang, Xiaopeng Ren, John C. Little, Ying Xu","doi":"10.1021/acs.est.5c05551","DOIUrl":"https://doi.org/10.1021/acs.est.5c05551","url":null,"abstract":"Water-based paints, despite being marketed as environmentally friendly, emit various chemicals of emerging concern (CECs) that may pose health risks indoors. This study characterizes CEC emissions from water-based paints through systematic experiments and modeling. Four CECs, covering a broad range of volatility, were tested experimentally. Results showed distinct emission patterns for chemicals with varying volatility: high-volatility CECs, like diethylene glycol butyl ether, exhibited rapid peak-and-decay emissions, while low-volatility triethylene glycol bis(2-ethylhexanoate) showed persistent emissions over 100 days. A dynamic mass transfer model was developed and validated against experimental data. The partition coefficient between polymer particles and air (<i>K</i><sub>pa</sub>) and the diffusion coefficient within the polymer (<i>D</i><sub>p</sub>) were identified as the key parameters governing emissions. The model classified emissions of 20 common CECs into short (<10 days), medium (10–100 days), and long-term (>1000 days) profiles, highlighting prolonged exposure risks for low-volatility compounds. Substrate effects showed that permeable substrates reduced initial emissions of volatile CECs but had minimal impact on long-term release. The model was applied to a residential indoor scenario, demonstrating its utility for exposure assessment. These findings improve the understanding of CEC emissions from water-based paints and provide valuable insights for more accurate risk assessments and safer product design.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"21 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711471","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}
Fluorinated microplastics (F-MPs), such as poly(vinylidene fluoride) (PVDF) and polytetrafluoroethylene (PTFE), are increasingly prevalent in environmental matrices due to their extensive industrial use, yet their chemical transformation under environmental aging remains unresolved. Here, we systematically elucidate the photochemical pathways governing radical formation, molecular fragmentation, and redox reactivity of F-MPs exposed to UV-A/H2O2 irradiation. Solid-state and spin-trapping electron-paramagnetic-resonance analyses reveal that the formation of persistent carbon-centered and fluorine-coupled radicals reaches 1015 spins g-1 on PVDF, accompanied by the generation of ten short-lived reactive species, including ·OH, O2·-, and CF2·. Subsequent C-F bond scission releases fluoride ions (up to 50 μmol g-1) and fluorinated molecular fragments structurally analogous to polyfluoroalkyl (PFAS) precursors (e.g., tetrafluoroethylene oxide, difluoroacetic acid, and trifluoroacetaldehyde). Concurrently, oxidative surface functionalization narrows the PVDF band gap and bolsters its oxidative potential by 5-fold, enabling the catalytic transformation of atrazine (a typical contaminant in water and soil) with a removal efficiency of 43.7 ± 3.2%. In contrast, PTFE exhibits minimal radical accessibility due to higher C-F bond dissociation energies and limited surface oxidation. These findings demonstrate that Photoaged F-MPs function as redox-active interfaces, vectors, and secondary PFAS sources, rather than presumed inert particulates, thus substantially expanding the paradigms of MPs' environmental reactivity and the contaminant fate.
{"title":"Release of Fluoro-Contained Free Radicals and Polyfluorinated-Like Molecules from Photoaged Fluorinated Microplastics: Identification and Formation Mechanisms.","authors":"Khaled Axel Djebbari,Leslie M Shor,Baikun Li","doi":"10.1021/acs.est.5c08970","DOIUrl":"https://doi.org/10.1021/acs.est.5c08970","url":null,"abstract":"Fluorinated microplastics (F-MPs), such as poly(vinylidene fluoride) (PVDF) and polytetrafluoroethylene (PTFE), are increasingly prevalent in environmental matrices due to their extensive industrial use, yet their chemical transformation under environmental aging remains unresolved. Here, we systematically elucidate the photochemical pathways governing radical formation, molecular fragmentation, and redox reactivity of F-MPs exposed to UV-A/H2O2 irradiation. Solid-state and spin-trapping electron-paramagnetic-resonance analyses reveal that the formation of persistent carbon-centered and fluorine-coupled radicals reaches 1015 spins g-1 on PVDF, accompanied by the generation of ten short-lived reactive species, including ·OH, O2·-, and CF2·. Subsequent C-F bond scission releases fluoride ions (up to 50 μmol g-1) and fluorinated molecular fragments structurally analogous to polyfluoroalkyl (PFAS) precursors (e.g., tetrafluoroethylene oxide, difluoroacetic acid, and trifluoroacetaldehyde). Concurrently, oxidative surface functionalization narrows the PVDF band gap and bolsters its oxidative potential by 5-fold, enabling the catalytic transformation of atrazine (a typical contaminant in water and soil) with a removal efficiency of 43.7 ± 3.2%. In contrast, PTFE exhibits minimal radical accessibility due to higher C-F bond dissociation energies and limited surface oxidation. These findings demonstrate that Photoaged F-MPs function as redox-active interfaces, vectors, and secondary PFAS sources, rather than presumed inert particulates, thus substantially expanding the paradigms of MPs' environmental reactivity and the contaminant fate.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"22 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145710933","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}
Xena Mansoura,Zezhen Cheng,Gregory W Vandergrift,Nurun Nahar Lata,Valentina Sola,Ashfiqur Rahman,Jeffery Dhas,Matthew A Marcus,Zihua Zhu,Jason M Tomlinson,Beat Schmid,Damao Zhang,Fan Mei,Swarup China
Ambient aerosol vertical profiles are critical for evaluating the role of aerosols in atmospheric chemistry and radiative transfer, but limited data on these profiles hinder our ability to fully assess their impact on the Earth's radiative balance. Here, we investigated the size-, time-, and altitude-resolved composition of individual particles and the bulk molecular composition of particle samples collected by an uncrewed aerial system─ArcticShark over the Southern Great Plains. Single-particle microanalysis shows that the free tropospheric (FT) samples are dominated (56-66%) by carbonaceous sulfate particles, while boundary layer (BL) samples are dominated (57-74%) by carbonaceous particles. Back-trajectory simulations suggest that FT particles are likely influenced by long-range transport and have undergone aqueous-phase processing. Conversely, in situ size distribution data show evidence of particle growth in the upper BL and just below the FT. This observation may indicate vertical transport of particles from an elevated aerosol layer in the FT, possibly linked to a new particle formation event. This observation is further supported by high-resolution molecular composition data, which reveals particle volatility increasing with increasing size, aligning with the growth event. This study aids in a fundamental understanding of the compositional and molecular specificity of vertically resolved organic aerosols to provide insights into particle size evolution for future atmospheric models.
{"title":"Physicochemical and Molecular Insights into the Boundary Layer and Free Troposphere Aerosol Interactions over the Southern Great Plains.","authors":"Xena Mansoura,Zezhen Cheng,Gregory W Vandergrift,Nurun Nahar Lata,Valentina Sola,Ashfiqur Rahman,Jeffery Dhas,Matthew A Marcus,Zihua Zhu,Jason M Tomlinson,Beat Schmid,Damao Zhang,Fan Mei,Swarup China","doi":"10.1021/acs.est.5c10903","DOIUrl":"https://doi.org/10.1021/acs.est.5c10903","url":null,"abstract":"Ambient aerosol vertical profiles are critical for evaluating the role of aerosols in atmospheric chemistry and radiative transfer, but limited data on these profiles hinder our ability to fully assess their impact on the Earth's radiative balance. Here, we investigated the size-, time-, and altitude-resolved composition of individual particles and the bulk molecular composition of particle samples collected by an uncrewed aerial system─ArcticShark over the Southern Great Plains. Single-particle microanalysis shows that the free tropospheric (FT) samples are dominated (56-66%) by carbonaceous sulfate particles, while boundary layer (BL) samples are dominated (57-74%) by carbonaceous particles. Back-trajectory simulations suggest that FT particles are likely influenced by long-range transport and have undergone aqueous-phase processing. Conversely, in situ size distribution data show evidence of particle growth in the upper BL and just below the FT. This observation may indicate vertical transport of particles from an elevated aerosol layer in the FT, possibly linked to a new particle formation event. This observation is further supported by high-resolution molecular composition data, which reveals particle volatility increasing with increasing size, aligning with the growth event. This study aids in a fundamental understanding of the compositional and molecular specificity of vertically resolved organic aerosols to provide insights into particle size evolution for future atmospheric models.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"141 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711152","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}
Bipolar membrane electrodialysis (BMED) is a promising technology for waste brine management, enabling acid and base production alongside brine dilution. However, divalent cations (Ca2+, Mg2+) cause severe alkaline scaling. This study investigates the mechanisms of scaling formation in BMED and its impact on acid–base production, highlighting the dependence on ion transport. Bidirectional migration of divalent cations and OH– through the cation exchange membrane (CEM) results in (1) heterogeneous surface crystallization on both sides of the CEM and the anion exchange layer of the bipolar membrane, and (2) bulk crystallization in salt and base solutions. Moreover, crystals depositing on the CEM reduce the effective membrane area and thus increase local current density, inducing local water splitting (LWS). The additional OH– generated from LWS elevates pH near the CEM and in the salt solution, intensifying scaling on the CEM and in the salt solution. Meanwhile, H+ from LWS migrates to the base solution, neutralizing it, while excess OH– accumulating in the salt solution migrates across the anion exchange membrane and neutralizes the acid. Apart from the revealed scaling-enhanced scaling and scaling-induced neutralization effects, scaling in the BMED stack also increases OH– leakage and stack resistance, decreases current efficiency, and causes irreversible performance loss even after cleaning. Overall, these findings underscore the critical role of ion migration and local electrochemical environment change in scaling behavior and acid–base production performance.
{"title":"Elucidating the Mechanisms of Ion Transport-Dependent Scaling and Its Influence on Acid–Base Production in Bipolar Membrane Electrodialysis","authors":"Yuqin Ni, Hong Liu, Qianhong She","doi":"10.1021/acs.est.5c11446","DOIUrl":"https://doi.org/10.1021/acs.est.5c11446","url":null,"abstract":"Bipolar membrane electrodialysis (BMED) is a promising technology for waste brine management, enabling acid and base production alongside brine dilution. However, divalent cations (Ca<sup>2+</sup>, Mg<sup>2+</sup>) cause severe alkaline scaling. This study investigates the mechanisms of scaling formation in BMED and its impact on acid–base production, highlighting the dependence on ion transport. Bidirectional migration of divalent cations and OH<sup>–</sup> through the cation exchange membrane (CEM) results in (1) heterogeneous surface crystallization on both sides of the CEM and the anion exchange layer of the bipolar membrane, and (2) bulk crystallization in salt and base solutions. Moreover, crystals depositing on the CEM reduce the effective membrane area and thus increase local current density, inducing local water splitting (LWS). The additional OH<sup>–</sup> generated from LWS elevates pH near the CEM and in the salt solution, intensifying scaling on the CEM and in the salt solution. Meanwhile, H<sup>+</sup> from LWS migrates to the base solution, neutralizing it, while excess OH<sup>–</sup> accumulating in the salt solution migrates across the anion exchange membrane and neutralizes the acid. Apart from the revealed scaling-enhanced scaling and scaling-induced neutralization effects, scaling in the BMED stack also increases OH<sup>–</sup> leakage and stack resistance, decreases current efficiency, and causes irreversible performance loss even after cleaning. Overall, these findings underscore the critical role of ion migration and local electrochemical environment change in scaling behavior and acid–base production performance.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"139 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145704712","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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