工业场地土壤Cr(VI)污染还原与稳定化的优化研究
Optimization Study on the Reduction and Stabilization of Cr(VI)Contamination in Industrial Site Soils
胡常巨 1王伟 1李磊勇 1邱丽雪 2徐俏 3管冬兴2
作者信息
- 1. 宁波市生态环保产业集团有限公司,浙江 宁波 315000
- 2. 浙江大学环境与资源学院,浙江杭州 310058
- 3. 中国科学院城市环境研究所,福建 厦门 361021;宁波(北仑)中科海西产业技术创新中心,浙江 宁波 315830
- 折叠
摘要
土壤中六价铬Cr(VI)污染的化学修复涉及价态还原和稳定化两个过程.对将土壤中高危害性的、高迁移性的Cr(VI)还原成低危害性、易被吸附的三价铬Cr(III),并进一步实现稳定化进行研究.以浙江省宁波市某工业场地的Cr污染土壤为修复对象,采用草酸、硫酸亚铁、尿素、凹凸棒土和零价铁等不同比例的还原剂,通过测定土壤中Cr(VI)的含量,比较 5 种还原剂对该污染土壤的还原作用.结合还原效果和原料成本,确定了 4 种不同比例的还原剂,即 1%零价铁、1%硫酸亚铁、0.5%凹凸棒土和 3%硫酸亚铁.将这 4 种还原剂两两组合投加到土壤中,比较还原效果;选用 4 种稳定化剂,包括生物炭、生石灰、钙镁磷肥和水溶性硅肥,投入到经还原剂还原的土壤中,加入质量比为 2%,通过测定土壤中Cr(VI)的含量,比较稳定化作用.结果显示:1%零价铁+1%硫酸亚铁处理组的还原率高达 70.2%,与其他处理组相比还原效果较好且成本较低,最终确定其为最优还原剂组合;2%生物炭的稳定效果最好,最终确定其为稳定化剂.综上所述,1%零价铁+1%硫酸亚铁和 2%生物炭的复合配方对Cr(VI)的还原与稳定化效果最佳,可在实际操作中作进一步验证.
Abstract
Chemical remediation of hexavalent chromium Cr(VI)contamination in soil involves two processes of reduction and stabilization.The aim of this study was to reduce the highly hazardous and highly mobile Cr(VI)in soil to the low hazardous and easily adsorbed trivalent chromium Cr(III),and further achieve stabilization.Chromium-contaminated soil from an industrial site in Ningbo,Zhejiang province,was selected for remediation.The effectiveness of different ratios of reducing agents,including oxalic acid,ferrous sulfate,urea,attapulgite clay,and zero-valent iron,was compared by measuring the Cr(VI)content in the soil.Based on reduction effectiveness and raw material costs,four different ratios of reducing agents were determined,namely 1%zero-valent iron,1%ferrous sulfate,0.5%attapulgite soil,and 3%ferrous sulfate.These four reducing agents were combined in pairs and added to the soil to compare their reduction effects.Four stabilizing agents,included biochar,quicklime,calcium-magnesium phosphate fertilizer and water-soluble silicon fertilizer were added to the reductant reduced soil with a mass ratio of 2%,and the Cr(VI)content in the soil was measured to evaluate the stabilizing effects.The results showed that the combination of 1%zero-valent iron and 1%ferrous sulfate achieved a reduction rate as high as 70.2%,demonstrated better reduction effects and lower costs compared to other treatments,so this combination was identified as the optimal reducing agent combination.The stabilization effect of 2%biochar was the best,and it was finally determined to be the stabilizer.In summary,the compound formulation of 1%zero-valent iron+1%ferrous sulfate and 2%biochar has the best reduction and stabilization effect on Cr(VI)which could be further verified in actual operation.
关键词
土壤污染/六价铬/化学修复/还原剂/稳定化剂Key words
soil contamination/hexavalent chromium/chemical remediation/reducing agents/stabilizing agents引用本文复制引用
基金项目
国家自然科学基金重点项目(42330703)
出版年
2024
NETL
NSTL
万方数据