In order to improve membrane reactor( MBR) performance for micro-polluted surface water treatment in start-up phase,removals of nitrogen and organic matters especially synthetic organic matters by MBR and a simultaneo...In order to improve membrane reactor( MBR) performance for micro-polluted surface water treatment in start-up phase,removals of nitrogen and organic matters especially synthetic organic matters by MBR and a simultaneous application of powdered activated carbon( PAC) with MBR( PAC-MBR) using flat sheet membrane are investigated. The results confirm that MBR treatment can be effective for the removal of organic matters including trace organics. The added PAC can improve contaminant removal efficiency especially in the beginning of operation when MBR cannot effectively remove contaminants and effluent satisfying quality standards is obtained. Moreover,the removal efficiency of target trace synthetic organics is investigated and the removal mechanism is discussed. Biodegradation by microorganism,rejection by filtration of membrane with biofilm and adsorption all contribute to the removal performance. Furthermore,volatile organic compounds can be removed by aeration. The filtration process is confirmed important for natural organic matters( NOM)removal in both MBR and PAC-MBR systems. Combining with PAC,the MBR can remove all fractions of NOM while the single MBR can hardly reduce fulvic or humic acid in water even during the steady operation.展开更多
This study explores a novel approach to biochar modification aimed at increasing persistent free radical(PFR)formation on biochar surfaces,thereby enhancing aniline removal via peroxymonosulfate(PMS)activation.By adju...This study explores a novel approach to biochar modification aimed at increasing persistent free radical(PFR)formation on biochar surfaces,thereby enhancing aniline removal via peroxymonosulfate(PMS)activation.By adjusting pyrolysis temperatures and doping ratios,optimal conditions were established.Spearman’s analysis highlighted the importance of C=C bonds,the ID/IG ratio,and pyridinic N in generating PFRs.The modified biochar derived at 500℃(MB500),in conjunction with the PMS system demonstrated impressive efficiency,achieving 92%aniline removal within 30 min.Detailed adsorption tests and active species detection indicated that aniline degradation occurred through both direct oxidation by PFRs and indirect oxidation by reactive species,particularly superoxide radicals(O_(₂)^(⋅⁻)).Furthermore,the synergistic effects of heteroatom nitrogen and Na_(2)CO_(3)modifications significantly impacted PFR formation and stability.These findings provide valuable insights into the mechanisms of PFR-mediated catalytic oxidation,highlighting the key roles of pyridinic rings,with or without oxygenated groups,in enhancing catalytic performance of biochar.This research advances the understanding of biochar surface chemistry and presents an effective strategy for developing high-performance biochar-based catalysts for environmental remediation,addressing the limitations of unmodified biochar through targeted surface modifications.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.51408149)
文摘In order to improve membrane reactor( MBR) performance for micro-polluted surface water treatment in start-up phase,removals of nitrogen and organic matters especially synthetic organic matters by MBR and a simultaneous application of powdered activated carbon( PAC) with MBR( PAC-MBR) using flat sheet membrane are investigated. The results confirm that MBR treatment can be effective for the removal of organic matters including trace organics. The added PAC can improve contaminant removal efficiency especially in the beginning of operation when MBR cannot effectively remove contaminants and effluent satisfying quality standards is obtained. Moreover,the removal efficiency of target trace synthetic organics is investigated and the removal mechanism is discussed. Biodegradation by microorganism,rejection by filtration of membrane with biofilm and adsorption all contribute to the removal performance. Furthermore,volatile organic compounds can be removed by aeration. The filtration process is confirmed important for natural organic matters( NOM)removal in both MBR and PAC-MBR systems. Combining with PAC,the MBR can remove all fractions of NOM while the single MBR can hardly reduce fulvic or humic acid in water even during the steady operation.
基金fouded by the General Program of Stable Support Plan for Universities in Shenzhen City(Grant No.GXWD20231130102759003)the National Natural Science Foundation of China(Grant No.42177044).
文摘This study explores a novel approach to biochar modification aimed at increasing persistent free radical(PFR)formation on biochar surfaces,thereby enhancing aniline removal via peroxymonosulfate(PMS)activation.By adjusting pyrolysis temperatures and doping ratios,optimal conditions were established.Spearman’s analysis highlighted the importance of C=C bonds,the ID/IG ratio,and pyridinic N in generating PFRs.The modified biochar derived at 500℃(MB500),in conjunction with the PMS system demonstrated impressive efficiency,achieving 92%aniline removal within 30 min.Detailed adsorption tests and active species detection indicated that aniline degradation occurred through both direct oxidation by PFRs and indirect oxidation by reactive species,particularly superoxide radicals(O_(₂)^(⋅⁻)).Furthermore,the synergistic effects of heteroatom nitrogen and Na_(2)CO_(3)modifications significantly impacted PFR formation and stability.These findings provide valuable insights into the mechanisms of PFR-mediated catalytic oxidation,highlighting the key roles of pyridinic rings,with or without oxygenated groups,in enhancing catalytic performance of biochar.This research advances the understanding of biochar surface chemistry and presents an effective strategy for developing high-performance biochar-based catalysts for environmental remediation,addressing the limitations of unmodified biochar through targeted surface modifications.
