铬污染土壤处理中的铬含量及形态变化

摘要

FeSO4 and Na2S were used as reducing agent to treat the chromium-contaminated purple soil.The content and speciation changes of chromium in the reduction process were studied.The experimental results showed that:When the amount of FeSO4 was 1.5％ (w),the content of leached Cr (Ⅵ)was decreased from (1 745.13 ± 27.93)mg/kg to (17.65 ± 2.28) mg/kg,the content of leached total chromium was decreased from (1 768.83 ± 57.24) mg/kg to (69.79 ± 8.61)mg/kg,and chromium is changed from water soluble carbonate bound state to the stable Fe-Mn bound state;When the amount of Na2S was 1.5％ (w),the content of leached Cr (Ⅵ) was decreased from (1 745.13 ± 27.93)mg/kg to (25.50 ± 0.12) mg/kg,the content of leached total chromium was decreased from (1 768.83 ± 57.24) mg/kg to (410.87 ± 12.83)mg/kg,and chromium is changed from water soluble carbonate bound state to Fe-Mn bound state and organic bound state.%采用FeSO4和Na2S作为还原剂处理铬污染紫色土壤,研究了还原过程中铬的含量及形态的变化.实验结果表明:当FeSO4加入量为1.5％(w,下同)时,浸出Cr(Ⅵ)含量由(1 745.13±27.93) mg/kg降至(17.65±2.28)mg/kg,浸出总铬含量由(1 768.83±57.24) mg/kg降至(69.79±8.61) mg/kg,铬形态由水溶+碳酸盐结合态转变到较稳定的铁锰结合态;当Na2S加入量为0.4％时,浸出Cr(Ⅵ)含量由(1 745.13±27.93) mg/kg降至(25.50±0.12) mg/kg,浸出总铬含量由(1 768.83±57.24) mg/kg降至(410.87±12.83) mg/kg,铬形态由水溶+碳酸盐结合态转变到铁锰结合态和有机结合态.