In this study, nanoscale zero-valent iron (NZVI) were immobilized within a chelating resin (DOW 3N). To investigate the effect of Fe loading on NZVI reactivity, three NZVI-resin composites with different Fe loadin...In this study, nanoscale zero-valent iron (NZVI) were immobilized within a chelating resin (DOW 3N). To investigate the effect of Fe loading on NZVI reactivity, three NZVI-resin composites with different Fe loading were obtained by preparing Fe(III) solution in 0, 30 and 70% (v/v) ethanol aqueous, respectively; the bromate was used as a model contami- nant. TEM reveals that increasing the Fe loading resulted in much larger size and poor dispersion of nanoscale iron particles. The results indicated that the removal efficiency of bromate and the rate constant (Kobs) were decreased with increasing the Fe loading. For the NZVI-resin composite with lower Fe loading, the removal efficiency ofbromate declined more significantly with the increase of DO concentrations. Under acidic conditions, decreasing the pH value had the most significant influence on NZVI- R3 with highest Fe loading for bromate removal; however, under alkaline conditions, the most significant influence of pH was on NZVI-R1 with lowest Fe loading. The effects of co-existing anions NO3, PO43- and HCO3- were also investigated. All of the co-existing anions showed the inhibition to bromate reduction.展开更多
4-Benzamido-TEMPO catalyzed oxidation system for conversion of a wide range of alcohols to the aldehydes or ketones with NaBrO_(3) under room temperature conditions has been developed.The credible,operationally con-ve...4-Benzamido-TEMPO catalyzed oxidation system for conversion of a wide range of alcohols to the aldehydes or ketones with NaBrO_(3) under room temperature conditions has been developed.The credible,operationally con-venient and economical,and condition mild oxidation protocol is particularly of interest in laboratory and in fine chemicals manufacture.展开更多
文摘In this study, nanoscale zero-valent iron (NZVI) were immobilized within a chelating resin (DOW 3N). To investigate the effect of Fe loading on NZVI reactivity, three NZVI-resin composites with different Fe loading were obtained by preparing Fe(III) solution in 0, 30 and 70% (v/v) ethanol aqueous, respectively; the bromate was used as a model contami- nant. TEM reveals that increasing the Fe loading resulted in much larger size and poor dispersion of nanoscale iron particles. The results indicated that the removal efficiency of bromate and the rate constant (Kobs) were decreased with increasing the Fe loading. For the NZVI-resin composite with lower Fe loading, the removal efficiency ofbromate declined more significantly with the increase of DO concentrations. Under acidic conditions, decreasing the pH value had the most significant influence on NZVI- R3 with highest Fe loading for bromate removal; however, under alkaline conditions, the most significant influence of pH was on NZVI-R1 with lowest Fe loading. The effects of co-existing anions NO3, PO43- and HCO3- were also investigated. All of the co-existing anions showed the inhibition to bromate reduction.
基金We are grateful to the financial support from the Na-tional Natural Science Foundation of China(No.21072055)the National High Technology Research and Development Program of China(863 Program)(No.2008AA06Z306).
文摘4-Benzamido-TEMPO catalyzed oxidation system for conversion of a wide range of alcohols to the aldehydes or ketones with NaBrO_(3) under room temperature conditions has been developed.The credible,operationally con-venient and economical,and condition mild oxidation protocol is particularly of interest in laboratory and in fine chemicals manufacture.