Pub Date : 2026-10-15DOI: 10.1016/j.seppur.2026.140573
Fangchong Han, Bin Zhang, Jun Ke, Lijun Niu, Jie Liu, Lidong Wang
Conventional single-atom catalysts (SACs) with symmetric coordination architectures feature uniform electron distribution and predominantly initiate radical-mediated pathways during peroxymonosulfate (PMS) activation, yet practical applicability of SACs is severely hampered by interferences from complex water matrices. In contrast, asymmetrically coordinated single-atom catalysts (AC-SACs) break the electronic symmetry around metal centers, enabling selective non-radical route dominance and thus representing a promising strategy for boosting catalytic performance. Unlike previous reviews, this review is the first to take asymmetric coordination as the central theme and systematically review AC-SACs for non-radical PMS activation. In particular, it innovatively discusses the formation mechanisms of non-radical pathways and analyzes the associated controversies. Four representative types of asymmetric coordination configurations are classified and linked to synthesis strategies, support materials, and advanced characterization techniques. Furthermore, the selectivity of reactive species is analyzed from mechanistic perspectives including localized polarization electric fields, d-band centers, and spin states, and practical application devices loaded with AC-SACs are discussed. Finally, the major challenges and future research directions in this emerging field are outlined, offering new insights for the rational design of high-efficiency PMS activation catalysts.
{"title":"Recent advances in asymmetrically coordinated single-atom catalysts for peroxymonosulfate activation toward non-radical pathways","authors":"Fangchong Han, Bin Zhang, Jun Ke, Lijun Niu, Jie Liu, Lidong Wang","doi":"10.1016/j.seppur.2026.140573","DOIUrl":"10.1016/j.seppur.2026.140573","url":null,"abstract":"<div><div>Conventional single-atom catalysts (SACs) with symmetric coordination architectures feature uniform electron distribution and predominantly initiate radical-mediated pathways during peroxymonosulfate (PMS) activation, yet practical applicability of SACs is severely hampered by interferences from complex water matrices. In contrast, asymmetrically coordinated single-atom catalysts (AC-SACs) break the electronic symmetry around metal centers, enabling selective non-radical route dominance and thus representing a promising strategy for boosting catalytic performance. Unlike previous reviews, this review is the first to take asymmetric coordination as the central theme and systematically review AC-SACs for non-radical PMS activation. In particular, it innovatively discusses the formation mechanisms of non-radical pathways and analyzes the associated controversies. Four representative types of asymmetric coordination configurations are classified and linked to synthesis strategies, support materials, and advanced characterization techniques. Furthermore, the selectivity of reactive species is analyzed from mechanistic perspectives including localized polarization electric fields, d-band centers, and spin states, and practical application devices loaded with AC-SACs are discussed. Finally, the major challenges and future research directions in this emerging field are outlined, offering new insights for the rational design of high-efficiency PMS activation catalysts.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"422 ","pages":"Article 140573"},"PeriodicalIF":9.1,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149204291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-10-15DOI: 10.1016/j.seppur.2026.140522
Q. Hong, X.H. Chen, L. Pang, Y. Huang, M.X. Fang, L. Jiang
For the monoethanolamine (MEA)-H2O-CO2 system, statistical associating fluid theory (SAFT) can implicitly represent chemical reactions through specific cross-association interactions, avoiding explicit ionic species and chemical equilibrium relations. However, CO2 absorption in aqueous MEA involves carbamate and bicarbonate pathways with CO2: MEA stoichiometric ratios of 1:2 and 1:1, respectively, and their relative contributions vary with loading and temperature. The existing models use two non-equivalent CO2 reactive sites to improve fitting, but these sites lack clear correspondence with the actual reaction pathways. Here, we develop a pathway-weighted association approach based on the perturbed-chain statistical associating fluid theory (PC-SAFT). Symmetric two-site and single-site association schemes represent the carbamate and bicarbonate pathways while a loading- and temperature-dependent pathway weight regulates their relative contributions. For 30 wt% aqueous MEA at CO2 loadings of 0.1–1.0 mol CO2/mol MEA and temperatures of 313.15–393.15 K, the average absolute relative deviation (AARD) for equilibrium CO2 partial pressure is 1.53%, compared with 15.59% for the asymmetric two-site model. Over 0.1–0.7 mol CO2/mol MEA, the carbamate fraction agrees with reference species distributions from an electrolyte non-random two-liquid (eNRTL) model with an AARD of 5.51%. For CO2 absorption enthalpy, the AARD decreases from 14.29% to 9.48%. The proposed approach may provide a basis for extension to other alkanolamine and polyamine systems involving multiple CO2 absorption pathways.
{"title":"Modeling of CO2 absorption in aqueous monoethanolamine with weighted carbamate and bicarbonate pathways","authors":"Q. Hong, X.H. Chen, L. Pang, Y. Huang, M.X. Fang, L. Jiang","doi":"10.1016/j.seppur.2026.140522","DOIUrl":"10.1016/j.seppur.2026.140522","url":null,"abstract":"<div><div>For the monoethanolamine (MEA)-H<sub>2</sub>O-CO<sub>2</sub> system, statistical associating fluid theory (SAFT) can implicitly represent chemical reactions through specific cross-association interactions, avoiding explicit ionic species and chemical equilibrium relations. However, CO<sub>2</sub> absorption in aqueous MEA involves carbamate and bicarbonate pathways with CO<sub>2</sub>: MEA stoichiometric ratios of 1:2 and 1:1, respectively, and their relative contributions vary with loading and temperature. The existing models use two non-equivalent CO<sub>2</sub> reactive sites to improve fitting, but these sites lack clear correspondence with the actual reaction pathways. Here, we develop a pathway-weighted association approach based on the perturbed-chain statistical associating fluid theory (PC-SAFT). Symmetric two-site and single-site association schemes represent the carbamate and bicarbonate pathways while a loading- and temperature-dependent pathway weight regulates their relative contributions. For 30 wt% aqueous MEA at CO<sub>2</sub> loadings of 0.1–1.0 mol CO<sub>2</sub>/mol MEA and temperatures of 313.15–393.15 K, the average absolute relative deviation (AARD) for equilibrium CO<sub>2</sub> partial pressure is 1.53%, compared with 15.59% for the asymmetric two-site model. Over 0.1–0.7 mol CO<sub>2</sub>/mol MEA, the carbamate fraction agrees with reference species distributions from an electrolyte non-random two-liquid (eNRTL) model with an AARD of 5.51%. For CO<sub>2</sub> absorption enthalpy, the AARD decreases from 14.29% to 9.48%. The proposed approach may provide a basis for extension to other alkanolamine and polyamine systems involving multiple CO<sub>2</sub> absorption pathways.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"422 ","pages":"Article 140522"},"PeriodicalIF":9.1,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149204786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-10-15DOI: 10.1016/j.seppur.2026.140582
Yuzhi Ming, Yan Zhang, Zhiyong Zheng, He Liu, Feifei Li, Feng Cao, Donghui Wen, Lyujun Chen
Pyrolysis-based biochar production represents a promising pathway for the resource utilization of salvaged blue-green algae. Since iron-based conditioning is commonly employed to enhance the dewaterability of algal slurry in practical treatment processes, this study systematically compared the effects of different iron conditioning methods (FeSO4, FeCl3, and Fenton) on the properties and catalytic performance of derived biochars. Iron doped and iron‑nitrogen co-doped biochars prepared from conditioned algae were evaluated for peroxymonosulfate (PMS) activation and antibiotic degradation. The iron‑nitrogen co-doped biochar derived from Fenton-conditioned algae (FZBC800U) exhibited superior performance, achieving 99.6% levofloxacin removal within 80 min via a singlet oxygen-dominated non-radical pathway. Characterization revealed that Fenton conditioning yielded the highest FeN species content, abundant pyridinic nitrogen, and optimal structural properties among the tested conditioning methods. The system maintained high efficiency across broad pH ranges of 3–11, demonstrated strong anti-interference capability, and showed good reusability. When applied to real pharmaceutical wastewater, it achieved 99.9% removal of total detected antibiotics. This work not only confirms the feasibility of converting algal biomass into efficient catalysts but also provides scientific guidance for selecting iron conditioning strategies in practical algal sludge treatment.
{"title":"Preparation of iron‑nitrogen co-doped biochar from blue-green algae to activate persulfate for antibiotic degradation: Effect of different iron conditioning options","authors":"Yuzhi Ming, Yan Zhang, Zhiyong Zheng, He Liu, Feifei Li, Feng Cao, Donghui Wen, Lyujun Chen","doi":"10.1016/j.seppur.2026.140582","DOIUrl":"10.1016/j.seppur.2026.140582","url":null,"abstract":"<div><div>Pyrolysis-based biochar production represents a promising pathway for the resource utilization of salvaged blue-green algae. Since iron-based conditioning is commonly employed to enhance the dewaterability of algal slurry in practical treatment processes, this study systematically compared the effects of different iron conditioning methods (FeSO<sub>4</sub>, FeCl<sub>3</sub>, and Fenton) on the properties and catalytic performance of derived biochars. Iron doped and iron‑nitrogen co-doped biochars prepared from conditioned algae were evaluated for peroxymonosulfate (PMS) activation and antibiotic degradation. The iron‑nitrogen co-doped biochar derived from Fenton-conditioned algae (FZBC800U) exhibited superior performance, achieving 99.6% levofloxacin removal within 80 min via a singlet oxygen-dominated non-radical pathway. Characterization revealed that Fenton conditioning yielded the highest Fe<img>N species content, abundant pyridinic nitrogen, and optimal structural properties among the tested conditioning methods. The system maintained high efficiency across broad pH ranges of 3–11, demonstrated strong anti-interference capability, and showed good reusability. When applied to real pharmaceutical wastewater, it achieved 99.9% removal of total detected antibiotics. This work not only confirms the feasibility of converting algal biomass into efficient catalysts but also provides scientific guidance for selecting iron conditioning strategies in practical algal sludge treatment.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"422 ","pages":"Article 140582"},"PeriodicalIF":9.1,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149204290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-10-12DOI: 10.1016/j.seppur.2026.140539
Dongkyu Kim, Sunyoung Oh, Woo Hyung Park, Ik-Jong Choi, Lauren Ye Seol Lee, Boram Gu
Reverse osmosis (RO) is widely used for seawater desalination, water treatment, and product concentration, yet long-term performance degradation remains difficult to predict because fouling and membrane deterioration arise from coupled physical, chemical, and biological phenomena under variable industrial conditions. We developed a hybrid modeling (HBM) framework combining a first-principles RO model (FPM) with a deep neural network and applied it to an industrial two-stage RO system concentrating byproducts from methionine fermentation. The framework used 251 days of plant data, with 205 daily-averaged observations retained after cleaning, and was benchmarked against DNN, SVM, and LSTM models using a chronologically held-out test period evaluated by expanding-window walk-forward validation. The HBM achieved competitive accuracy while maintaining physical consistency, with the lowest RMSE for final retentate pressure (0.15 bar vs. 0.48 bar) and overall acetic acid (Ac) rejection (8.15% vs. 15.12%) relative to the best data-driven benchmark. Mean flow and Ac mass-balance errors also remained on the order of , substantially below those of the purely data-driven models. In addition, the HBM estimated otherwise unmeasurable stage-dependent degradation parameters. Water permeability decreased by approximately 52% and 45% in Stages 1 and 2 within the first ~20 days, while feed-channel friction factors increased by approximately 1.3% and 2.5% within the first ~60 days, with the Stage 2 increase comparable to run-to-run variability. These results show that the HBM combines predictive accuracy, physical consistency, and interpretable stage-wise information, supporting industrial process monitoring and future fouling management.
反渗透（RO）广泛用于海水淡化、水处理和产品浓缩，但长期性能退化仍然难以预测，因为在可变的工业条件下，污染和膜退化是由耦合的物理、化学和生物现象引起的。我们开发了一种混合建模（HBM）框架，将第一性原理反渗透模型（FPM）与深度神经网络相结合，并将其应用于蛋氨酸发酵副产物的工业两级反渗透系统。该框架使用了251 天的工厂数据，在清理后保留了205天的每日平均观测值，并使用按时间顺序的测试周期（通过扩展窗口向前走验证进行评估）对DNN、SVM和LSTM模型进行基准测试。HBM在保持物理一致性的同时获得了具有竞争力的准确性，相对于最佳数据驱动基准，最终保留压力（0.15 bar vs. 0.48 bar）和总体乙酸（Ac）截留（8.15% vs. 15.12%）的RMSE最低。平均流量和交流质量平衡误差也保持在10 - 5%左右，大大低于纯数据驱动模型的误差。此外，HBM估计了其他不可测量的与阶段相关的退化参数。第1阶段和第2阶段的渗透率在前20 天内分别下降了约52%和45%，而进料通道摩擦系数在前60 天内分别增加了约1.3%和2.5%，其中第2阶段的增加与井间的变化相当。这些结果表明，HBM结合了预测准确性、物理一致性和可解释的阶段信息，支持工业过程监控和未来的污垢管理。
{"title":"Hybrid first-principles and neural-network modeling for reverse osmosis: predicting long-term performance degradation under industrial data uncertainty","authors":"Dongkyu Kim, Sunyoung Oh, Woo Hyung Park, Ik-Jong Choi, Lauren Ye Seol Lee, Boram Gu","doi":"10.1016/j.seppur.2026.140539","DOIUrl":"10.1016/j.seppur.2026.140539","url":null,"abstract":"<div><div>Reverse osmosis (RO) is widely used for seawater desalination, water treatment, and product concentration, yet long-term performance degradation remains difficult to predict because fouling and membrane deterioration arise from coupled physical, chemical, and biological phenomena under variable industrial conditions. We developed a hybrid modeling (HBM) framework combining a first-principles RO model (FPM) with a deep neural network and applied it to an industrial two-stage RO system concentrating byproducts from methionine fermentation. The framework used 251 days of plant data, with 205 daily-averaged observations retained after cleaning, and was benchmarked against DNN, SVM, and LSTM models using a chronologically held-out test period evaluated by expanding-window walk-forward validation. The HBM achieved competitive accuracy while maintaining physical consistency, with the lowest RMSE for final retentate pressure (0.15 bar vs. 0.48 bar) and overall acetic acid (Ac) rejection (8.15% vs. 15.12%) relative to the best data-driven benchmark. Mean flow and Ac mass-balance errors also remained on the order of <span><math><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup><mo>%</mo></math></span>, substantially below those of the purely data-driven models. In addition, the HBM estimated otherwise unmeasurable stage-dependent degradation parameters. Water permeability decreased by approximately 52% and 45% in Stages 1 and 2 within the first ~20 days, while feed-channel friction factors increased by approximately 1.3% and 2.5% within the first ~60 days, with the Stage 2 increase comparable to run-to-run variability. These results show that the HBM combines predictive accuracy, physical consistency, and interpretable stage-wise information, supporting industrial process monitoring and future fouling management.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"422 ","pages":"Article 140539"},"PeriodicalIF":9.1,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149204787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-09-01DOI: 10.1016/j.seppur.2026.139982
Keren Lu, Haiyan Jing, Huijuan Jia, Hua Pan, Tan Ke, Xixiong Zhang, Xiaogang Li, Suzhen Huang, Mingxing Shi
Lignin-derived hierarchical porous carbons (HPCs) are promising low-cost electrode materials for capacitive deionization (CDI) defluoridation due to their tunable pores and rich surface chemistry. Here, sodium lignosulfonate (SLS) was used as precursor, and Na2CO3, NaHCO3 and Na2C2O4 were systematically employed as activators to prepare SLS-derived HPCs. The effects of activator type on morphology, pore structure, surface chemistry and defect distribution were comprehensively evaluated. Among them, Na2CO3-mediated HPC (Na2CO3-HPC) exhibited wrinkled, loosely stacked sheet-like structures, a high specific surface area of 1652.92 m2 g−1, large pore volume of 1.77 cm3 g−1, high N/S content and improved hydrophilicity. Raman mapping and TEM revealed defect-rich carbon frameworks with locally graphitized domains, providing abundant active sites, reduced charge-transfer resistance and accelerated ion transport. In CDI tests using 200 mg L−1 NaF, Na2CO3-HPC achieved a maximum SAC of 11.38 mg F− g−1 at 1.4 V and an ASAR of 3.72 mg F− g−1 min−1 in the time-dependent test. In a separate cycling experiment, it retained approximately 80.9% of its first-cycle capacity after 50 adsorption–desorption cycles. First-principles calculations showed that vacancy effects were configuration- and ion-dependent: DV strengthened both F and Na adsorption, whereas MV and TV mainly strengthened F adsorption, while heteroatoms further modulated adsorption in an ion- and configuration-dependent manner. This work demonstrates that inorganic sodium salts can coordinately regulate hierarchical porosity, vacancy defects, and surface chemistry to improve the CDI defluoridation performance of lignin-based carbons.
{"title":"Activator-mediated hierarchical porosity and defect–surface engineering of lignin-based carbons for fluoride removal by capacitive deionization","authors":"Keren Lu, Haiyan Jing, Huijuan Jia, Hua Pan, Tan Ke, Xixiong Zhang, Xiaogang Li, Suzhen Huang, Mingxing Shi","doi":"10.1016/j.seppur.2026.139982","DOIUrl":"10.1016/j.seppur.2026.139982","url":null,"abstract":"<div><div>Lignin-derived hierarchical porous carbons (HPCs) are promising low-cost electrode materials for capacitive deionization (CDI) defluoridation due to their tunable pores and rich surface chemistry. Here, sodium lignosulfonate (SLS) was used as precursor, and Na<sub>2</sub>CO<sub>3</sub>, NaHCO<sub>3</sub> and Na<sub>2</sub>C<sub>2</sub>O<sub>4</sub> were systematically employed as activators to prepare SLS-derived HPCs. The effects of activator type on morphology, pore structure, surface chemistry and defect distribution were comprehensively evaluated. Among them, Na<sub>2</sub>CO<sub>3</sub>-mediated HPC (Na<sub>2</sub>CO<sub>3</sub>-HPC) exhibited wrinkled, loosely stacked sheet-like structures, a high specific surface area of 1652.92 m<sup>2</sup> g<sup>−1</sup>, large pore volume of 1.77 cm<sup>3</sup> g<sup>−1</sup>, high N/S content and improved hydrophilicity. Raman mapping and TEM revealed defect-rich carbon frameworks with locally graphitized domains, providing abundant active sites, reduced charge-transfer resistance and accelerated ion transport. In CDI tests using 200 mg L<sup>−1</sup> NaF, Na<sub>2</sub>CO<sub>3</sub>-HPC achieved a maximum SAC of 11.38 mg F<sup>−</sup> g<sup>−1</sup> at 1.4 V and an ASAR of 3.72 mg F<sup>−</sup> g<sup>−1</sup> min<sup>−1</sup> in the time-dependent test. In a separate cycling experiment, it retained approximately 80.9% of its first-cycle capacity after 50 adsorption–desorption cycles. First-principles calculations showed that vacancy effects were configuration- and ion-dependent: DV strengthened both F and Na adsorption, whereas MV and TV mainly strengthened F adsorption, while heteroatoms further modulated adsorption in an ion- and configuration-dependent manner. This work demonstrates that inorganic sodium salts can coordinately regulate hierarchical porosity, vacancy defects, and surface chemistry to improve the CDI defluoridation performance of lignin-based carbons.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"416 ","pages":"Article 139982"},"PeriodicalIF":9.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148870645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-08-31DOI: 10.1016/j.seppur.2026.139986
Lin Dou, Xinyi Liu, Yujia Li, Yuqin Hu, Junbo Zhong
Photocatalytic conversion of CO2 into high-value solar fuels is a promising technology to simultaneously tackle energy scarcity and fulfill carbon neutrality targets. Nevertheless, the practical application of this technology is restricted by insufficient CO2 adsorption capacity, rapid recombination of photogenerated charge carriers, and sluggish surface reaction kinetics. In this study, an S-scheme Pr6O11/MoS2 heterojunction with abundant sulfur vacancies (SVs) was rationally fabricated via a solvothermal method combined with post-calcination treatment. CO2 adsorption results confirm that the SVs and increased surface area can substantially improve the CO2 adsorption performance of the photocatalyst. The strong interfacial coupling interaction between Pr6O11 and MoS2 constructs an efficient S-scheme charge transfer pathway. The pathway effectively promotes the spatial separation of photogenerated electron-hole (e−/h+) pairs, while preserving the superior redox capability of charge carriers from both semiconductor components. In-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was adopted to explore the photocatalytic mechanism. The characterization results prove that *HCO3 acts as the major reaction intermediate, and the photoreduction reaction of CO2 mainly proceeds via a bicarbonate-mediated pathway, thereby realizing the selective generation of CO products. Owing to the synergistic effects of SVs mediated CO2 adsorption and activation, and S-scheme interfacial charge transfer, the optimized Pr6O11/MoS2 heterojunction achieves an improved CO evolution rate (2.77 μmol·g−1·h−1), which is 4.9 times and 2.9 times of that over MoS2 and Pr6O11, respectively. This work elucidates the cooperative effect of SVs and interfacial charges dynamics in regulating photocatalytic CO2 reduction and provides a reliable avenue for the design and fabrication of high-performance MoS2-based photocatalysts for solar energy conversion.
{"title":"Sulfur vacancies-enriched S-scheme Pr6O11/MoS2 heterojunction for photocatalytic CO2 reduction","authors":"Lin Dou, Xinyi Liu, Yujia Li, Yuqin Hu, Junbo Zhong","doi":"10.1016/j.seppur.2026.139986","DOIUrl":"10.1016/j.seppur.2026.139986","url":null,"abstract":"<div><div>Photocatalytic conversion of CO<sub>2</sub> into high-value solar fuels is a promising technology to simultaneously tackle energy scarcity and fulfill carbon neutrality targets. Nevertheless, the practical application of this technology is restricted by insufficient CO<sub>2</sub> adsorption capacity, rapid recombination of photogenerated charge carriers, and sluggish surface reaction kinetics. In this study, an S-scheme Pr<sub>6</sub>O<sub>11</sub>/MoS<sub>2</sub> heterojunction with abundant sulfur vacancies (SVs) was rationally fabricated via a solvothermal method combined with post-calcination treatment. CO<sub>2</sub> adsorption results confirm that the SVs and increased surface area can substantially improve the CO<sub>2</sub> adsorption performance of the photocatalyst. The strong interfacial coupling interaction between Pr<sub>6</sub>O<sub>11</sub> and MoS<sub>2</sub> constructs an efficient S-scheme charge transfer pathway. The pathway effectively promotes the spatial separation of photogenerated electron-hole (e<sup>−</sup>/h<sup>+</sup>) pairs, while preserving the superior redox capability of charge carriers from both semiconductor components. In-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was adopted to explore the photocatalytic mechanism. The characterization results prove that *HCO<sub>3</sub> acts as the major reaction intermediate, and the photoreduction reaction of CO<sub>2</sub> mainly proceeds via a bicarbonate-mediated pathway, thereby realizing the selective generation of CO products. Owing to the synergistic effects of SVs mediated CO<sub>2</sub> adsorption and activation, and S-scheme interfacial charge transfer, the optimized Pr<sub>6</sub>O<sub>11</sub>/MoS<sub>2</sub> heterojunction achieves an improved CO evolution rate (2.77 μmol·g<sup>−1</sup>·h<sup>−1</sup>), which is 4.9 times and 2.9 times of that over MoS<sub>2</sub> and Pr<sub>6</sub>O<sub>11</sub>, respectively. This work elucidates the cooperative effect of SVs and interfacial charges dynamics in regulating photocatalytic CO<sub>2</sub> reduction and provides a reliable avenue for the design and fabrication of high-performance MoS<sub>2</sub>-based photocatalysts for solar energy conversion.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"416 ","pages":"Article 139986"},"PeriodicalIF":9.1,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148870287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rational regulation of cobalt active sites to selectively generate high-valent cobalt-oxo (Co(IV) = O) species remains challenging for efficient peroxymonosulfate (PMS) activation in advanced oxidation processes. Herein, we develop a boron-regulated cobalt/nitrogen-doped carbon catalyst (Co@B-NCs) through a facile pyrolysis strategy to manipulate the electronic microenvironment of isolated Co sites for enhanced PMS activation toward sulfamethoxazole (SMX) degradation. Boron incorporation induces surface electronic reconstruction by forming B–N/B–O-related environments, increasing Co electron deficiency, and promoting interfacial charge redistribution. Consequently, the Co@B-NCs/PMS system exhibits a 23-fold enhancement in degradation kinetics compared with the B-free Co@NCs/PMS counterpart, achieving rapid and complete SMX removal. Systematic mechanistic investigations collectively support that B regulation facilitates PMS adsorption and interfacial electron transfer, thereby establishing a favorable environment for proton-coupled electron transfer (PCET) assisted PMS activation and the involvement of Co(IV) = O intermediates. The generated Co(IV) = O species, together with 1O2 and ·O2−, contribute synergistically to non-radical and radical oxidation multipath for efficient pollutant transformation. Moreover, the Co@B-NCs/PMS system demonstrates excellent stability, broad pH adaptability, strong resistance to coexisting water constituents, broad-spectrum degradation capability, and sustained performance in continuous-flow operation. ECOSAR-based toxicity assessment and plant germination experiments further indicate reduced predicted ecotoxicity and phytotoxicity of the treated system. This work provides fundamental insights into boron-mediated electronic modulation of cobalt active centers and offers a rational strategy for designing robust PMS activation catalysts based on high-valent metal-oxo chemistry for practical wastewater remediation.
{"title":"Boron-induced high-valent cobalt-oxo generation in N-doped carbon for efficient peroxymonosulfate activation","authors":"Yilin Liu, Yanfeng Lu, Yi Qiang, Yiming Xie, Jiaquan Zhang, Yu Huang","doi":"10.1016/j.seppur.2026.139972","DOIUrl":"10.1016/j.seppur.2026.139972","url":null,"abstract":"<div><div>The rational regulation of cobalt active sites to selectively generate high-valent cobalt-oxo (Co(IV) = O) species remains challenging for efficient peroxymonosulfate (PMS) activation in advanced oxidation processes. Herein, we develop a boron-regulated cobalt/nitrogen-doped carbon catalyst (Co@B-NCs) through a facile pyrolysis strategy to manipulate the electronic microenvironment of isolated Co sites for enhanced PMS activation toward sulfamethoxazole (SMX) degradation. Boron incorporation induces surface electronic reconstruction by forming B–N/B–O-related environments, increasing Co electron deficiency, and promoting interfacial charge redistribution. Consequently, the Co@B-NCs/PMS system exhibits a 23-fold enhancement in degradation kinetics compared with the B-free Co@NCs/PMS counterpart, achieving rapid and complete SMX removal. Systematic mechanistic investigations collectively support that B regulation facilitates PMS adsorption and interfacial electron transfer, thereby establishing a favorable environment for proton-coupled electron transfer (PCET) assisted PMS activation and the involvement of Co(IV) = O intermediates. The generated Co(IV) = O species, together with <sup>1</sup>O<sub>2</sub> and ·O<sub>2</sub><sup>−</sup>, contribute synergistically to non-radical and radical oxidation multipath for efficient pollutant transformation. Moreover, the Co@B-NCs/PMS system demonstrates excellent stability, broad pH adaptability, strong resistance to coexisting water constituents, broad-spectrum degradation capability, and sustained performance in continuous-flow operation. ECOSAR-based toxicity assessment and plant germination experiments further indicate reduced predicted ecotoxicity and phytotoxicity of the treated system. This work provides fundamental insights into boron-mediated electronic modulation of cobalt active centers and offers a rational strategy for designing robust PMS activation catalysts based on high-valent metal-oxo chemistry for practical wastewater remediation.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"416 ","pages":"Article 139972"},"PeriodicalIF":9.1,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148870286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-08-31DOI: 10.1016/j.seppur.2026.139983
Kitae Kim, Bomi Kim, Toan Anh Pham, Yong-Yoon Ahn, Minjin Choi, Jungwon Kim
Bromate (BrO3−) is a toxic disinfection byproduct commonly formed during oxidative water treatment, and its reduction to relatively nontoxic bromide (Br−) is an effective strategy for detoxifying BrO3−-contaminated water. In this study, we investigated the reduction of BrO3− to Br− by ferrous ions (Fe2+) in frozen solution at −20 °C and compared it with that in aqueous solution at 25 °C. At initial concentrations of 500 μM Fe2+ and 50 μM BrO3− at pH 3.0, BrO3− was completely reduced within 20 min in the frozen solution, with Br− identified as the sole stable bromine product detected under the applied analytical conditions. In contrast, only 10.3 and 16.4 μM BrO3− were reduced after 20 and 120 min, respectively, in the aqueous solution. The accelerated reduction of BrO3− by Fe2+ upon freezing was primarily attributed to the freeze-concentration effect, whereby Fe2+, BrO3−, and protons are enriched in liquid-like layers during freezing. This effect was verified by measuring the spatial distribution of BrO3− and the apparent pH of the frozen samples using Raman microscopy and UV − visible spectroscopy, respectively. The reduction of BrO3− by Fe2+ in frozen solution proceeded rapidly under acidic conditions below pH 6.0, whereas only limited reduction occurred under basic conditions above pH 9.0, because BrO3− reduction by Fe2+ requires protons and Fe2+ is oxidized to hydrolyzed Fe(III) species and/or Fe(III) (hydr)oxide particles under basic conditions. Water impurities, including HCO3−, H2PO4−, NO3−, and humic acid, did not significantly inhibit BrO3− reduction, and efficient BrO3− reduction was achieved in tap water containing various ions. Furthermore, BrO3− reduction proceeded efficiently under outdoor natural-freezing conditions without requiring external electrical energy input. This study demonstrates that freezing markedly accelerates the Fe2+-mediated reduction of BrO3− to Br−, even in complex water matrices, and highlights the potential of natural freezing as a passive, energy-efficient approach to detoxifying BrO3−-contaminated water in cold environments.
{"title":"Freezing-accelerated bromate reduction by ferrous ions: Mechanism, kinetics, and implications for water treatment","authors":"Kitae Kim, Bomi Kim, Toan Anh Pham, Yong-Yoon Ahn, Minjin Choi, Jungwon Kim","doi":"10.1016/j.seppur.2026.139983","DOIUrl":"10.1016/j.seppur.2026.139983","url":null,"abstract":"<div><div>Bromate (BrO<sub>3</sub><sup>−</sup>) is a toxic disinfection byproduct commonly formed during oxidative water treatment, and its reduction to relatively nontoxic bromide (Br<sup>−</sup>) is an effective strategy for detoxifying BrO<sub>3</sub><sup>−</sup>-contaminated water. In this study, we investigated the reduction of BrO<sub>3</sub><sup>−</sup> to Br<sup>−</sup> by ferrous ions (Fe<sup>2+</sup>) in frozen solution at −20 °C and compared it with that in aqueous solution at 25 °C. At initial concentrations of 500 μM Fe<sup>2+</sup> and 50 μM BrO<sub>3</sub><sup>−</sup> at pH 3.0, BrO<sub>3</sub><sup>−</sup> was completely reduced within 20 min in the frozen solution, with Br<sup>−</sup> identified as the sole stable bromine product detected under the applied analytical conditions. In contrast, only 10.3 and 16.4 μM BrO<sub>3</sub><sup>−</sup> were reduced after 20 and 120 min, respectively, in the aqueous solution. The accelerated reduction of BrO<sub>3</sub><sup>−</sup> by Fe<sup>2+</sup> upon freezing was primarily attributed to the freeze-concentration effect, whereby Fe<sup>2+</sup>, BrO<sub>3</sub><sup>−</sup>, and protons are enriched in liquid-like layers during freezing. This effect was verified by measuring the spatial distribution of BrO<sub>3</sub><sup>−</sup> and the apparent pH of the frozen samples using Raman microscopy and UV − visible spectroscopy, respectively. The reduction of BrO<sub>3</sub><sup>−</sup> by Fe<sup>2+</sup> in frozen solution proceeded rapidly under acidic conditions below pH 6.0, whereas only limited reduction occurred under basic conditions above pH 9.0, because BrO<sub>3</sub><sup>−</sup> reduction by Fe<sup>2+</sup> requires protons and Fe<sup>2+</sup> is oxidized to hydrolyzed Fe(III) species and/or Fe(III) (hydr)oxide particles under basic conditions. Water impurities, including HCO<sub>3</sub><sup>−</sup>, H<sub>2</sub>PO<sub>4</sub><sup>−</sup>, NO<sub>3</sub><sup>−</sup>, and humic acid, did not significantly inhibit BrO<sub>3</sub><sup>−</sup> reduction, and efficient BrO<sub>3</sub><sup>−</sup> reduction was achieved in tap water containing various ions. Furthermore, BrO<sub>3</sub><sup>−</sup> reduction proceeded efficiently under outdoor natural-freezing conditions without requiring external electrical energy input. This study demonstrates that freezing markedly accelerates the Fe<sup>2+</sup>-mediated reduction of BrO<sub>3</sub><sup>−</sup> to Br<sup>−</sup>, even in complex water matrices, and highlights the potential of natural freezing as a passive, energy-efficient approach to detoxifying BrO<sub>3</sub><sup>−</sup>-contaminated water in cold environments.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"416 ","pages":"Article 139983"},"PeriodicalIF":9.1,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148870517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polyamide nanofiltration (PA NF) membranes are widely used in water treatment. However, the separation performance of these membranes has been constrained by the permeability-selectivity trade-off, thereby limiting their practical engineering applications. Herein, a covalent organic framework (Py-Da-COF) with a uniform pore structure was designed as an interlayer for interfacial polymerization (IP), enabling the fabrication of high-performance thin-film nanocomposite (TFN) NF membranes. First, imine-linked Py-Da-COF materials with a hollow tubular morphology, good crystallinity, and well-ordered pore channels were synthesized via a solvothermal method. Then, the COF material was deposited onto a supporting membrane via vacuum-assisted filtration, followed by interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC) to construct the modified (P-TFN) membrane. The effect of COF loading on membrane structure and performance was systematically investigated. The introduction of the COF interlayer reduced the polymerization rate by delaying the diffusion of amine monomers, which resulted in the formation of an ultra-thin polyamide layer. Meanwhile, the porous COF structure enriched the amine monomers and improved the interfacial hydration environment. Additionally, the Py-Da-COF induced a rough membrane surface and introduced microporous transport channels, thereby increasing the pore size and enhancing the interfacial bonding strength. The results displayed that at the optimized COF loading of 1.4 μg cm−2, the P-TFN membrane exhibited a pure water permeability of 24.6 L m−2 h−1 bar−1, approximately 2.5 times that of the unmodified TFC membrane, while maintaining a Na2SO4 rejection of 98%. A continuous 100 h operation test further demonstrated the excellent long-term stability of the fabricated membrane. This work provides a new design strategy for developing high-performance nanofiltration membranes and is expected to broaden the application prospects of TFN membranes in the treatment of industrial wastewater and brackish water containing inorganic salts and phosphates.
聚酰胺纳滤膜在水处理中有着广泛的应用。然而，这些膜的分离性能受到渗透选择性权衡的限制，从而限制了它们的实际工程应用。本文设计了一种具有均匀孔隙结构的共价有机骨架（Py-Da-COF）作为界面聚合（IP）的中间层，从而制备了高性能薄膜纳米复合材料（TFN） NF膜。首先，通过溶剂热法合成了具有中空管状、良好结晶度和有序孔道的亚胺连接Py-Da-COF材料。然后，通过真空辅助过滤将COF材料沉积在支撑膜上，然后将哌嗪（PIP）和三甲酰氯（TMC）进行界面聚合，构建改性（P-TFN）膜。系统研究了COF加载对膜结构和性能的影响。COF中间层的引入延缓了胺类单体的扩散，从而降低了聚合速度，形成了超薄聚酰胺层。同时，多孔COF结构丰富了胺类单体，改善了界面水化环境。此外，Py-Da-COF诱导了粗糙的膜表面，并引入了微孔传输通道，从而增加了孔径，增强了界面结合强度。结果表明，在优化的COF负载为1.4 μg cm−2时，P-TFN膜的纯水渗透率为24.6 L m−2 h−1 bar−1，约为未改性TFC膜的2.5倍，同时保持98%的Na2SO4截留率。100 h的连续运行试验进一步证明了所制备的膜具有良好的长期稳定性。本研究为开发高性能纳滤膜提供了新的设计策略，有望拓宽TFN膜在处理含无机盐和磷酸盐的工业废水和微咸水方面的应用前景。
{"title":"Covalent organic framework interlayered polyamide films for advanced nanofiltration","authors":"Shuangqiao Han, Xueqi Tao, Yuping Tong, Pengjia Zhu, Guang Yuan, Weiying Wang, Rui Li, Huixian Wang, Xiao Wang","doi":"10.1016/j.seppur.2026.139975","DOIUrl":"10.1016/j.seppur.2026.139975","url":null,"abstract":"<div><div>Polyamide nanofiltration (PA NF) membranes are widely used in water treatment. However, the separation performance of these membranes has been constrained by the permeability-selectivity trade-off, thereby limiting their practical engineering applications. Herein, a covalent organic framework (Py-Da-COF) with a uniform pore structure was designed as an interlayer for interfacial polymerization (IP), enabling the fabrication of high-performance thin-film nanocomposite (TFN) NF membranes. First, imine-linked Py-Da-COF materials with a hollow tubular morphology, good crystallinity, and well-ordered pore channels were synthesized via a solvothermal method. Then, the COF material was deposited onto a supporting membrane via vacuum-assisted filtration, followed by interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC) to construct the modified (P-TFN) membrane. The effect of COF loading on membrane structure and performance was systematically investigated. The introduction of the COF interlayer reduced the polymerization rate by delaying the diffusion of amine monomers, which resulted in the formation of an ultra-thin polyamide layer. Meanwhile, the porous COF structure enriched the amine monomers and improved the interfacial hydration environment. Additionally, the Py-Da-COF induced a rough membrane surface and introduced microporous transport channels, thereby increasing the pore size and enhancing the interfacial bonding strength. The results displayed that at the optimized COF loading of 1.4 μg cm<sup>−2</sup>, the P-TFN membrane exhibited a pure water permeability of 24.6 L m<sup>−2</sup> h<sup>−1</sup> bar<sup>−1</sup>, approximately 2.5 times that of the unmodified TFC membrane, while maintaining a Na<sub>2</sub>SO<sub>4</sub> rejection of 98%. A continuous 100 h operation test further demonstrated the excellent long-term stability of the fabricated membrane. This work provides a new design strategy for developing high-performance nanofiltration membranes and is expected to broaden the application prospects of TFN membranes in the treatment of industrial wastewater and brackish water containing inorganic salts and phosphates.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"416 ","pages":"Article 139975"},"PeriodicalIF":9.1,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148871001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-08-31DOI: 10.1016/j.seppur.2026.139962
Behnam Rezazadeh, Mohammad Sirousazar
The extraction of energy from biogas offers a practical solution to reduce reliance on fossil fuels while simultaneously addressing the issue of global warming. Membrane technology shows considerable promise for economically viable biogas upgrading due to its low energy requirements and environmental sustainability. This has stimulated extensive research into the development of CO₂-selective membranes with enhanced separation performance. In this study, we present an innovative strategy to improve CO₂ separation using a facilitated transport membrane incorporating Arg-Gly-Asp (RGD) a small tripeptide rather as fixed carriers within a poly (ether-block-amide) (PEBA) matrix. The large size and chain configuration of the RGD macromolecules within the PEBA matrix increase the fractional free volume (FFV) and create additional diffusion pathways. This modification reduces the diffusion resistance associated with carrier-to-carrier transport. Gas permeability measurements show that the optimal membrane, PE/RGD (1:1), achieves a CO₂ permeability of 920 Barrer and a CO₂/CH₄ selectivity of 95. These values represent improvements of 265% and 58%, respectively, compared to the pristine PEBA membrane. Moreover, the optimized PE/RGD (1,1) membrane demonstrates stable long-term performance over 200 h at 5 bar and 25 °C. These results highlight the potential of RGD as an effective additive for enhancing the performance of the PEBA membrane, enabling separation properties that surpass the 2008 Robeson upper bound and supporting the development of high-performance membranes for industrial applications.
{"title":"High-performance PEBA facilitated transport membranes incorporating RGD tripeptide for CO₂/CH₄ separation via reduced carrier transport resistance","authors":"Behnam Rezazadeh, Mohammad Sirousazar","doi":"10.1016/j.seppur.2026.139962","DOIUrl":"10.1016/j.seppur.2026.139962","url":null,"abstract":"<div><div>The extraction of energy from biogas offers a practical solution to reduce reliance on fossil fuels while simultaneously addressing the issue of global warming. Membrane technology shows considerable promise for economically viable biogas upgrading due to its low energy requirements and environmental sustainability. This has stimulated extensive research into the development of CO₂-selective membranes with enhanced separation performance. In this study, we present an innovative strategy to improve CO₂ separation using a facilitated transport membrane incorporating Arg-Gly-Asp (RGD) a small tripeptide rather as fixed carriers within a poly (ether-<em>block</em>-amide) (PEBA) matrix. The large size and chain configuration of the RGD macromolecules within the PEBA matrix increase the fractional free volume (FFV) and create additional diffusion pathways. This modification reduces the diffusion resistance associated with carrier-to-carrier transport. Gas permeability measurements show that the optimal membrane, PE/RGD (1:1), achieves a CO₂ permeability of 920 Barrer and a CO₂/CH₄ selectivity of 95. These values represent improvements of 265% and 58%, respectively, compared to the pristine PEBA membrane. Moreover, the optimized PE/RGD (1,1) membrane demonstrates stable long-term performance over 200 h at 5 bar and 25 °C. These results highlight the potential of RGD as an effective additive for enhancing the performance of the PEBA membrane, enabling separation properties that surpass the 2008 Robeson upper bound and supporting the development of high-performance membranes for industrial applications.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"416 ","pages":"Article 139962"},"PeriodicalIF":9.1,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148871003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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