ZVI/Air体系修复砷污染土壤的研究

Remediation of Arsenic Contaminated Soil by ZVI/Air System

采用ZVI/Air体系对模拟砷污染土壤与实际砷污染土壤进行修复。研究了ZVI投加量、Air曝气速率与pH对修复效果的影响,初步探讨了砷的稳定化机理,并应用于实际砷污染土壤的修复。研究结果表明,在20 g砷浓度为500 mg/kg的模拟污染土壤中加入0.3 g铁粉,固液比1∶20,曝气速度为0.02 m3/h,常温常压下反应50 min,模拟污染土与实际污染土中砷浸出液浓度均下降到5 mg/L以下,满足《危险废物鉴别标准浸出毒性鉴别》(GB5085.3-2007)的要求。

Zero-valent iron plus air system, namely ZVI/Air system, was investigated for remediation of arsenic- contaminated soil. The laboratory studies with simulated and practical soil samples found that dosage of ZVI and pH value were two main factors affecting remediation of the contaminated soil. Results of the study showed that under the normal condition in terms of temperature and pressure, when 0.3 g ZVI was added into Ascontaminated soil （concentration of 500 mg/kg ） with solid-liquid ratio 1：20, and 0.02 m3/h of aeration rate for the reaction of 50 min, arsenic concentration of leachates from the soil declined to less than 5 mg/L, lower than the concentration limit required by the relevant national standard.