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
The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNOx catalysts.This study investigated the sulfation mechanism of the CoMn2O4/CeTiOx(CMC...The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNOx catalysts.This study investigated the sulfation mechanism of the CoMn2O4/CeTiOx(CMCT)catalyst during the selective catalytic reduction of NOx with NH3 under conditions containing H2O and SO2 at 150℃.Employing a comprehensive suite of time-resolved analysis and characterization techniques,the evolution of sulfate species was systematically categorized into three stages:initial rapid surface sulfate accumulation,the transformation of surface sulfates to bulk metal sulfates,and partial sulfates decomposition after the removal of H2O and SO2.These findings indicate that bulk metal sulfates irreversibly deactivate the catalyst by distorting active component lattices and consuming oxygen vacancies,whereas surface sulfates(including ammonium sulfates and surface-coordinated metal sulfates)cause reversible performance loss through decomposition.Furthermore,the competitive adsorption of H2O and SO2 significantly influences the catalytic efficiency,with H2O suppressing SO2 adsorption while simultaneously enhancing the formation of Brönsted acid sites.This research underscores the critical role of sulfate dynamics on catalyst performance,revealing the enhanced SO2 resistance of the Eley-Rideal mechanism facilitated by the Ce-Ti support relative to the Langmuir-Hinshelwood pathway.Collectively,the study unravels the complex interplay of sulfate dynamics influencing catalyst performance and provides potential approaches to mitigate deactivation in demanding atmospheric conditions.展开更多
The removal of four dissolved organic matter(DOM) fractions, non-acid hydrophobics,hydrophobic acids, hydrophilics and transphilics, was achieved by coagulation-UV/H_2O_2 oxidation in post-pharmaceutical wastewater(Ph...The removal of four dissolved organic matter(DOM) fractions, non-acid hydrophobics,hydrophobic acids, hydrophilics and transphilics, was achieved by coagulation-UV/H_2O_2 oxidation in post-pharmaceutical wastewater(PhW W). Coagulation with Polyferric chloride(PFC), Polymeric ferric sulfate(PFS) and Polymeric aluminum ferric chloride(PAFC) was studied separately to evaluate the effects of the initial pH and coagulant dosage. The coagulation-UV/H_2O_2 oxidation method resulted in much higher reduction rates for dissolved organic carbon(DOC)(by 75%) and UV254(by 92%) than coagulation or UV/H_2O_2 oxidation alone. The proportion of non-acid hydrophobics, hydrophobic acids, transphilics and hydrophilics removed by coagulation was 54%, 49%, 27% and 12 %, while the combined treatment removed 92%, 87%,70% and 39%, respectively. Parallel factor analysis(PARAFAC) of fluorescence measurements revealed that the humic-like fluorescent component C4 showed the highest removal(by 44%)during the coagulation stage. After coagulation-UV/H_2O_2 treatment, the humic-like fluorescent component C3 had the highest removal(by 72%), whereas xenobiotic organic fluorescent components C1 and C4 remained recalcitrant to decomposition. Significant correlations(R2> 0.8)between C1 and the hydrophobic acids and non-acid hydrophobics suggested the possibility of using fluorescence spectroscopy as an effective tool to assess variations in DOM fraction treatment efficacy in coagulation-UV/H_2O_2 systems. After the combined treatment, toxic inhibition of cellular activity by post PhW W decreased from 88% to 47% and biodegradability increased from 0.1 to 0.52.展开更多
制备了负载在Na Y分子筛上的Fe Cu Mn Y复合催化剂,并对其在非均相UV Fe Cu Mn Y H2O2体系中催化氧化4BS染料废水进行了研究.结果表明,非均相UV Fe Cu Mn Y H2O2体系对4BS染料废水的处理具有很高的效率.在基准条件下,反应时间为20min时...制备了负载在Na Y分子筛上的Fe Cu Mn Y复合催化剂,并对其在非均相UV Fe Cu Mn Y H2O2体系中催化氧化4BS染料废水进行了研究.结果表明,非均相UV Fe Cu Mn Y H2O2体系对4BS染料废水的处理具有很高的效率.在基准条件下,反应时间为20min时,废水中4BS的去除率达到了93 7%.与均相UV Fenton体系不同,非均相UV Fe Cu Mn Y H2O2体系在碱性条件下(pH=10 5)仍可高效去除CODCr.动力学研究得到催化氧化4BS废水的模型方程,该模型可以为非均相UV Fe Cu Mn Y H2O2体系处理高色度的实际染料废水提供指导.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.
摘要The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNOx catalysts.This study investigated the sulfation mechanism of the CoMn2O4/CeTiOx(CMCT)catalyst during the selective catalytic reduction of NOx with NH3 under conditions containing H2O and SO2 at 150℃.Employing a comprehensive suite of time-resolved analysis and characterization techniques,the evolution of sulfate species was systematically categorized into three stages:initial rapid surface sulfate accumulation,the transformation of surface sulfates to bulk metal sulfates,and partial sulfates decomposition after the removal of H2O and SO2.These findings indicate that bulk metal sulfates irreversibly deactivate the catalyst by distorting active component lattices and consuming oxygen vacancies,whereas surface sulfates(including ammonium sulfates and surface-coordinated metal sulfates)cause reversible performance loss through decomposition.Furthermore,the competitive adsorption of H2O and SO2 significantly influences the catalytic efficiency,with H2O suppressing SO2 adsorption while simultaneously enhancing the formation of Brönsted acid sites.This research underscores the critical role of sulfate dynamics on catalyst performance,revealing the enhanced SO2 resistance of the Eley-Rideal mechanism facilitated by the Ce-Ti support relative to the Langmuir-Hinshelwood pathway.Collectively,the study unravels the complex interplay of sulfate dynamics influencing catalyst performance and provides potential approaches to mitigate deactivation in demanding atmospheric conditions.
基金supported by the National Key Scientific and Technological Project for Water Pollution Control and Management (Nos.2012ZX07202-005,2012ZX07202-002,2014 ZX07216001-2)
摘要The removal of four dissolved organic matter(DOM) fractions, non-acid hydrophobics,hydrophobic acids, hydrophilics and transphilics, was achieved by coagulation-UV/H_2O_2 oxidation in post-pharmaceutical wastewater(PhW W). Coagulation with Polyferric chloride(PFC), Polymeric ferric sulfate(PFS) and Polymeric aluminum ferric chloride(PAFC) was studied separately to evaluate the effects of the initial pH and coagulant dosage. The coagulation-UV/H_2O_2 oxidation method resulted in much higher reduction rates for dissolved organic carbon(DOC)(by 75%) and UV254(by 92%) than coagulation or UV/H_2O_2 oxidation alone. The proportion of non-acid hydrophobics, hydrophobic acids, transphilics and hydrophilics removed by coagulation was 54%, 49%, 27% and 12 %, while the combined treatment removed 92%, 87%,70% and 39%, respectively. Parallel factor analysis(PARAFAC) of fluorescence measurements revealed that the humic-like fluorescent component C4 showed the highest removal(by 44%)during the coagulation stage. After coagulation-UV/H_2O_2 treatment, the humic-like fluorescent component C3 had the highest removal(by 72%), whereas xenobiotic organic fluorescent components C1 and C4 remained recalcitrant to decomposition. Significant correlations(R2> 0.8)between C1 and the hydrophobic acids and non-acid hydrophobics suggested the possibility of using fluorescence spectroscopy as an effective tool to assess variations in DOM fraction treatment efficacy in coagulation-UV/H_2O_2 systems. After the combined treatment, toxic inhibition of cellular activity by post PhW W decreased from 88% to 47% and biodegradability increased from 0.1 to 0.52.
摘要制备了负载在Na Y分子筛上的Fe Cu Mn Y复合催化剂,并对其在非均相UV Fe Cu Mn Y H2O2体系中催化氧化4BS染料废水进行了研究.结果表明,非均相UV Fe Cu Mn Y H2O2体系对4BS染料废水的处理具有很高的效率.在基准条件下,反应时间为20min时,废水中4BS的去除率达到了93 7%.与均相UV Fenton体系不同,非均相UV Fe Cu Mn Y H2O2体系在碱性条件下(pH=10 5)仍可高效去除CODCr.动力学研究得到催化氧化4BS废水的模型方程,该模型可以为非均相UV Fe Cu Mn Y H2O2体系处理高色度的实际染料废水提供指导.