研究报告
陈喆,房丽莎,谭韵盈,汤叶涛,仇荣亮.CMC-nZVI对高硫矿山土壤中铜的固定效果及机理[J].环境科学学报,2017,37(11):4336-4343
CMC-nZVI对高硫矿山土壤中铜的固定效果及机理
- Immobilization of Cu in high sulfate mine soil using stabilized nonoscale zero-valent iron
- 基金项目：环保公益性行业科研专项（No.201509037）；广东省自然科学基金（No.2014A030313200）；广州市科技支撑项目（No.201607010065）；高校基本业务费项目（No.15lgjc36）
- 作者
- 单位
- 陈喆
- 1. 中山大学环境科学与工程学院, 广州 510275;3. 广西环境污染控制理论与技术重点实验室, 桂林理工大学环境科学与工程学院, 桂林 541004
- 房丽莎
- 中山大学环境科学与工程学院, 广州 510275
- 谭韵盈
- 中山大学环境科学与工程学院, 广州 510275
- 汤叶涛
- 1. 中山大学环境科学与工程学院, 广州 510275;2. 广东省环境污染控制与修复技术重点实验室, 广州 510275
- 仇荣亮
- 1. 中山大学环境科学与工程学院, 广州 510275;2. 广东省环境污染控制与修复技术重点实验室, 广州 510275
- 摘要：纳米零价铁（Nanoscale zero-valent iron， nZVI）因具有较大比表面积和较强还原能力，常被用于原位修复变价重金属污染土壤，而对其应用于高硫富铜矿山土壤的修复及机理研究却鲜见报道.本研究以羧甲基纤维素-纳米零价铁（CMC-nZVI）为供试材料，以广东省大宝山矿区高硫富铜土壤为供试土壤，按水土比1 g：5 mL将CMC-nZVI与矿山土壤混合均匀，通过毒性淋溶提取、重金属形态和酸可挥发性硫化物提取等实验，探究了CMC-nZVI对矿山土壤中Cu的固定效果及机制.结果表明：1 CMC-nZVI对高硫土壤中的Cu具有极好的固定效果，毒性淋溶提取实验结果表明，nZVI处理土壤中Cu的浸出浓度低于15 mg·kg-1，达到安全标准；2 nZVI可促进厌氧微生物的活性，促进土壤中大量硫酸盐被还原，因此Cu可能被FeS、FeS2吸附或直接生成硫化物沉淀，最终固定于土壤中；3 新生成的无定形或微晶型次级铁矿物易通过吸附或共沉淀将游离的Cu（II）固定.
- Abstract：Due to its greater specific surface area and higher reducing ability, nano-scale zero-valent iron (nZVI) has been commonly used for in-situ remediation of polyvalent heavy metal contaminated soils. However, its application and mechanism for the remediation of copper (Cu) and sulfate rich mine soils have been rarely reported. In this study, nZVI was synthesized and stabilized with sodium carboxymethylcellulose (CMC). CMC-nZVI, as well as Cu and sulfate rich soil collected from Dabao mountain mining area, Guangdong Province, were then used as experimental materials. CMC-nZVI mixed in the 1.456‰ ethanol solution was applied to soil at a soil to solution radio of 1 g: 5 mL. By analyzing the consequence of Toxicity Characteristic Leaching Procedure (TCLP), the speciation transformation of heavy metals and the generation of acid-volatile sulfides (AVS) were studied, and the possible Cu immobilization mechanism of CMC-nZVI in sulfate rich soil was proposed. The results showed that 1 CMC-nZVI was markedly efficient in Cu immobilization, which was proved by the fact that Cu concentration in the TCLP leachate was reduced to meet the safety standard of 15 mg·kg-1 after the treatment of CMC-nZVI. 2 CMC-nZVI could enhance the activity of anaerobic microorganisms and thus promote the reduction of sulfate, which in turn facilitated the adsorption of Cu to FeS and FeS2 or the formation of Cu sulfide as a precipitate. 3 the formation of amorphous or microcrystalline secondary Fe minerals could immobilize Cu by sorption and co-precipitation.
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