改性芬顿试剂修复农药污染土壤的工艺条件优化

在农药污染土壤中加入乙二胺四乙酸二钠(EDTA-2Na)改性传统芬顿试剂,研究化学氧化修复处理土壤中氯代有机物和苯系物的效果,探究EDTA-2Na、H₂O₂、FeSO₄浓度和H₂O₂投加次数对土壤中苯、1,2-二氯苯降解率的影响。结果表明:加入与Fe ²⁺物质的量比为1∶1的EDTA-2Na,苯的降解率提高了29.6个百分点,1,2-二氯苯的降解率提高了26.4个百分点;相同试验条件下,苯、1,2-二氯苯的降解率随着EDTA-2Na、H₂O₂、FeSO₄浓度和H₂O₂投加次数的增加而上升,然后逐步趋于稳定;适宜工艺参数是H₂O₂浓度为3.0 mmol∕g,n(H₂O₂)∶n(FeSO₄)∶n(EDTA-2Na)为10∶1∶1(n为物质的量),反应时间为2 h,H₂O₂分4次投加,此时苯的降解率最高达86.0%,1,2-二氯苯的降解率最高达83.6%。

Condition optimization of pesticide contaminated soils remediation by modified Fenton reagent

Fenton reagent modified by EDTA-2Na was applied to study the chemical oxidation remediation of chlorinated organics and BTEX in pesticide contaminated soils. The effects of EDTA-2Na, H2O2, FeSO4 dosage and H2O2 dosing times on pollutants degradation rate were studied. The results showed that the degradation rate of benzene was increased by 29.6 percentage points and that of 1,2-dichlorobenzene by 26.4 percentage points when EDTA-2Na was added in the ratio of 1∶1 to Fe 2+. Under the same experimental conditions, the degradation rates of benzene, 1, 2-dichlorobenzene increased with the addition of EDTA-2Na, H2O2, FeSO4, H2O2 concentrations, as well as with H2O2 dosing times, and then gradually stabilized. The suitable process parameters were identified as follows: H2O2 dosage 3.0 mmol∕g, n(H2O2)∶n(FeSO4)∶n(EDTA-2Na)=10∶1∶1, and reaction time 2 hours, and H2O2 added within 4 times. Under these conditions, the degradation rate of benzene was high up to 86.0%, and that of 1,2-dichlorobenzene was up to 83.6%.