Sequential and combined soil washing tests of Na2EDTA and phosphoric acids were conducted to remediation soil contaminated with arsenic and cationic metals (cadmium, copper, and lead) at a former metal smelter. The aim of the testing was to improve the heavy metals removal efficiency, and investigate mechanism of the influence of soil minerals on washing efficiency, including the influence on soil mineral, metal oxides, and functional groups of soil surface. The results indicated that the combined washing of Na2EDTA and phosphoric acid was effective in removing both arsenic and cationic metals from contaminated soil and had synergy effect for most target metals. The results of metal removal efficiency indicated that the washing agent, washing mode, and washing times influenced the removal efficiencies of arsenic and cationic metals. The spectroscopic analysis demonstrated that sequential and combined washings were effective in dissolving and reforming soil minerals compared with single washing. The promoted complexation, ligand exchange, desorption and inhibition of adsorption resulted in the synergistic effect for most target metals under combined washing.

中文翻译：

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通过 Na2EDTA 和磷酸洗涤修复冶炼厂污染土壤中的砷阳离子金属：去除效率和矿物转化

对原金属冶炼厂受砷和阳离子金属（镉、铜和铅）污染的土壤进行了连续和组合的 Na2EDTA 和磷酸洗土试验。试验的目的是提高重金属去除效率，研究土壤矿物质对洗涤效率的影响机制，包括对土壤矿物质、金属氧化物和土壤表面官能团的影响。结果表明，Na2EDTA和磷酸联合洗涤对污染土壤中的砷和阳离子金属均能有效去除，对大多数目标金属具有协同作用。金属去除率结果表明，清洗剂、清洗方式和清洗次数影响砷和阳离子金属的去除效率。光谱分析表明，与单次洗涤相比，连续洗涤和组合洗涤在溶解和改造土壤矿物质方面是有效的。在联合洗涤下，促进络合、配体交换、解吸和吸附抑制导致对大多数目标金属的协同作用。