热活化过硫酸钠耦合甲酸技术研究——处理水溶液中四氯化碳与六价铬污染

The removal performance of carbon tetrachloride and Cr(Ⅵ) in aqueous solution by thermally-activated persulfate/formic acid process

以甲酸为活化剂,耦合热活化过硫酸钠技术产生还原性二氧化碳阴离子自由基(CO_2^-),从而还原去除水溶液中四氯化碳(CT)和Cr(Ⅵ),考察过硫酸钠和甲酸初始浓度的影响以及复合污染处理效果.结果表明:当过硫酸钠与甲酸浓度均为100mmol/L时,单独CT或Cr(Ⅵ)分别在120min、60min内基本完全去除(50℃),且污染物去除效率随过硫酸钠及甲酸浓度升高而增强.在CT和Cr(Ⅵ)复合污染体系中,Cr(Ⅵ)的存在能够抑制CT降解,且抑制程度随Cr(Ⅵ)初始浓度升高而提高,但Cr(Ⅵ)去除率随CT初始浓度增大而升高.加入CO_2^-猝灭剂(甲基紫精)能够抑制CT降解,但促进Cr(Ⅵ)去除,表明有机物的存在能够增强Cr(Ⅵ)去除效率.

Carbon tetrachloride (CT) and hexavalent chromium removal performances were investigated by the thermalactivation of persulfate, in the presence of formic acid to turn the oxidizing capacity of the reaction mixture into areductive one by the generation of carbon dioxide anion radicals (CO2??). The Effects of initial concentrations of persulfateand formic acid on CT and Cr(VI) removal were evaluated respectively. For single pollutant system, when the initialpersulfate and formic acid concentrations were both 100mmol/L, CT and Cr (VI) could be almost completely removed in120min and 60min at 50℃, respectively. In addition, the removal efficiencies of CT and Cr (VI) increased with increasingpersulfate and formic dosage. For the combined pollutants system, CT degradation efficiency was found to decrease withincreasing Cr (VI) concentrations. However, Cr (VI) removal was increased with an increase in CT concentrations. CTdegradation was inhibited with the addition of methyl viologen as CO2?? scavenger, while an enhanced Cr (VI) reductionwas observed, indicating that the addition of organic substances may shift to favor Cr (VI) removal in thermally-activatedpersulfate/formic process.