摘要
通过药剂投加比为3.3%和6.7%的两组实验,分别对比了混合均匀度为100%、67%、33%条件下,不同时间点土壤砷浸出浓度的变化情况及其与理论计算浓度的差异,验证了假达标风险确实存在,且风险随着药剂投加量的增加和混合不均匀度的增加而升高,同时,由于硫酸铁本身具有较好的稳定性,“假达标”风险不会随时间的延长而完全消失。此外,还探索了磷酸二氢钾和焦磷酸钠对消除土壤中残留硫酸铁药剂的有效性,结果表明磷酸二氢钾是一种有效的残留Fe 3+药剂竞争剂,有助于降低修复后土壤样品假达标风险,但存在活化土壤As的风险,作为残留药剂去除剂时,需要严格控制投加量,防止土壤As被大幅活化;焦磷酸钠对残留硫酸铁干扰消除效果不明显,且对土壤As有活化风险,不建议作为残留药剂去除剂。
Stabilization of ferric sulfate is an important technology for remediation of arsenic-contaminated soil,but residual agents formed by excessive addition and uneven mixing would conduct secondary remediation in the process of soil leaching test,resulting in the risk of falsely meeting the standard.In this paper,the changes of soil arsenic leaching concentration at different time points and the differences with the theoretical calculated concentration were compared under the conditions of mixing uniformity of 100%,67%and 33%,respectively,through two groups of experiments with the dosage ratio of 3.3%and 6.7%.It found out that the risk of falsely meeting the standard did exist.The risk increased with the increasing dosage and mixing unevenness.At the same time,because ferric sulfate itself has good stability,the risk would not completely disappear with the extension of time.In addition,this paper explored the soil of effectiveness of eliminating the residual ferric sulfate using potassium dihydrogen phosphate and sodium pyrophosphate.The results showed that the potassium dihydrogen phosphate is a kind of effective chemicals residue Fe 3+competitive agent,which helped to reduce the false target risk,but there was a risk of activating soil arsenic,and it was necessary to strictly control the dosage to prevent soil arsenic from being greatly activated.Sodium pyrophosphate had no obvious effect on the elimination of residual ferric sulfate,and had a risk of activation of soil arsenic,so it was not recommended to be used as residual agent.
作者
李敏敏
董慧
魏恒
吴见珣
和丽萍
龙伟
曾沛艺
唐嫚
庞景理
LI Min-min;Dong Hui;WEI Heng;WU Jian-xun;HE Li-ping;LONG Wei;ZENG Pei-yi;TANG Man;PANG Jing-li(Yunnan Research Academy of Eco-environmental Sciences,Kunming Yunnan 650034,China)
出处
《环境科学导刊》
2022年第1期31-36,共6页
Environmental Science Survey
基金
2018年中央土壤污染防治专项资金支持项目“云南省土壤环境管理体系构建及关键修复技术研究与示范项目”。
关键词
砷污染土壤
硫酸铁
假达标
正磷酸盐
焦磷酸盐
arsenic contaminated soil
ferric sulfate
falsely meeting the standard
orthophosphate
pyrophosphate
