The degradation of atrazine(ATZ),sulfamethoxazole(SMX)and metoprolol(MET)in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter(ID).Results showed t...The degradation of atrazine(ATZ),sulfamethoxazole(SMX)and metoprolol(MET)in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter(ID).Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H2O2reactors following the pseudo first-order kinetics(R2>0.92).However,the steady-state assumption(SSA)kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient.With the increase of H2O2dosage,the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents,which could be explained by the different reactivities of the pollutants towards HO·.A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate,but the change in energy efficiency was much more complicated.In reality,the electrical energy per order(EEO)of the investigated VUV/UV/H2O2treatments ranged between 0.14–0.20,0.07–0.14 and 0.09–0.26 k Wh/m3/order for ATZ,SMX and MET,respectively,with the lowest EEOfor each pollutant obtained under varied H2O2dosages and reactor IDs.This study has demonstrated the efficiency of VUV/UV/H2O2process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors,and elaborated the influential mechanisms of H2O2dosage and reactor ID on the reactor performances.展开更多
Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N...Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N4 coordination)electrode for oxygen reduction reaction(ORR)via a two-electron pathway to make H2O2 in acidic media.The current density of the single-Co-atom electrode reached 51 mA/cm2 at 0.1 V vs reversible hydrogen electrode,lasting for more than 10 hours of continuous operation with H2O2 selectivity greater than 80%.Toward practical application,the single-Co-atom electrode was directly used to assemble an electrochemical cell to produce H2O2 at a rate of 676 mol/kgcat/h with a cell voltage of about 1.6 V.展开更多
为了考察UV/H_2O_2-活性炭过滤对水体中消毒副产物和条件致病菌的控制效果,采用原水-加氯、原水-活性炭过滤-加氯以及原水-UV/H_2O_2-活性炭过滤-加氯消毒进行了对比研究。对不同处理出水中溶解性有机碳(DOC)、生物可降解有机碳(BDOC)...为了考察UV/H_2O_2-活性炭过滤对水体中消毒副产物和条件致病菌的控制效果,采用原水-加氯、原水-活性炭过滤-加氯以及原水-UV/H_2O_2-活性炭过滤-加氯消毒进行了对比研究。对不同处理出水中溶解性有机碳(DOC)、生物可降解有机碳(BDOC)、有机物不同结构组成、消毒副产物、总细菌16S r RNA、三磷酸腺苷(ATP)及条件致病菌等相关指标进行测定分析。结果表明,UV/H_2O_2-活性炭过滤通过去除有机物中富里酸和腐殖酸类物质可以有效控制DOC浓度和后续消毒过程中消毒副产物三卤甲烷和卤乙酸类物质特别是三氯甲烷、二氯乙酸和三氯乙酸的生成。另外,UV/H_2O_2高级氧化也可以有效灭活颗粒黏附态和自由悬浮态的微生物,而UV/H_2O_2-活性炭过滤可以很好地控制BDOC浓度,再通过后续加氯消毒后微生物再生长能力弱,微生物活性也得到有效抑制,该工艺可以很好地控制微生物包括条件致病菌嗜肺军团菌和鸟分枝杆菌的生长。UV/H_2O_2-活性炭过滤可以很好地控制后续加氯消毒过程中消毒副产物的生成和条件致病菌的生长,有一定的应用前景。展开更多
基金supported by the National Natural Science Foundation of China(No.51908536)the Ministry of Science and Technology of China(No.2018YFE0204103)。
摘要The degradation of atrazine(ATZ),sulfamethoxazole(SMX)and metoprolol(MET)in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter(ID).Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H2O2reactors following the pseudo first-order kinetics(R2>0.92).However,the steady-state assumption(SSA)kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient.With the increase of H2O2dosage,the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents,which could be explained by the different reactivities of the pollutants towards HO·.A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate,but the change in energy efficiency was much more complicated.In reality,the electrical energy per order(EEO)of the investigated VUV/UV/H2O2treatments ranged between 0.14–0.20,0.07–0.14 and 0.09–0.26 k Wh/m3/order for ATZ,SMX and MET,respectively,with the lowest EEOfor each pollutant obtained under varied H2O2dosages and reactor IDs.This study has demonstrated the efficiency of VUV/UV/H2O2process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors,and elaborated the influential mechanisms of H2O2dosage and reactor ID on the reactor performances.
基金This study was supported by the funds from the Singapore Ministry of Education Academic Research Fund,Tier 1:RG111/15 and RG10/16 and Tier 2:MOE2016-T2-2 to 004.
摘要Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N4 coordination)electrode for oxygen reduction reaction(ORR)via a two-electron pathway to make H2O2 in acidic media.The current density of the single-Co-atom electrode reached 51 mA/cm2 at 0.1 V vs reversible hydrogen electrode,lasting for more than 10 hours of continuous operation with H2O2 selectivity greater than 80%.Toward practical application,the single-Co-atom electrode was directly used to assemble an electrochemical cell to produce H2O2 at a rate of 676 mol/kgcat/h with a cell voltage of about 1.6 V.
摘要为了考察UV/H_2O_2-活性炭过滤对水体中消毒副产物和条件致病菌的控制效果,采用原水-加氯、原水-活性炭过滤-加氯以及原水-UV/H_2O_2-活性炭过滤-加氯消毒进行了对比研究。对不同处理出水中溶解性有机碳(DOC)、生物可降解有机碳(BDOC)、有机物不同结构组成、消毒副产物、总细菌16S r RNA、三磷酸腺苷(ATP)及条件致病菌等相关指标进行测定分析。结果表明,UV/H_2O_2-活性炭过滤通过去除有机物中富里酸和腐殖酸类物质可以有效控制DOC浓度和后续消毒过程中消毒副产物三卤甲烷和卤乙酸类物质特别是三氯甲烷、二氯乙酸和三氯乙酸的生成。另外,UV/H_2O_2高级氧化也可以有效灭活颗粒黏附态和自由悬浮态的微生物,而UV/H_2O_2-活性炭过滤可以很好地控制BDOC浓度,再通过后续加氯消毒后微生物再生长能力弱,微生物活性也得到有效抑制,该工艺可以很好地控制微生物包括条件致病菌嗜肺军团菌和鸟分枝杆菌的生长。UV/H_2O_2-活性炭过滤可以很好地控制后续加氯消毒过程中消毒副产物的生成和条件致病菌的生长,有一定的应用前景。