Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
Department of Marine Environmental Engineering, National Kaohsiung Marine University, Kaohsiung City, Taiwan.
Environ Sci Pollut Res Int. 2018 Feb;25(6):5231-5242. doi: 10.1007/s11356-017-9235-7. Epub 2017 May 20.
The extraction efficiency of heavy metals from soils using three forms of gamma poly-glutamic acid (γ-PGA) as the washing agents was investigated. Controlling factors including agent concentrations, extraction time, pH, and liquid to soil ratio were evaluated to determine the optimum operational conditions. The distribution of heavy metal species in soils before and after extraction processes was analyzed. Up to 46 and 74% of heavy metal removal efficiencies were achieved with one round and a sequential extraction process using H-bonding form of γ-PGA (200 mM) with washing time of 40 min, liquid to solid ratio of 10 to 1, and pH of 6. Major heavy metal removal mechanisms were (1) γ-PGA-promoted dissolution and (2) complexation of heavy metal with free carboxyl groups in γ-PGA, which resulted in heavy metal desorption from soils. Metal species on soils were redistributed after washing, and soils were remediated without destruction of soil structures and productivity.
研究了三种形式的γ-聚谷氨酸（γ-PGA）作为洗涤剂从土壤中提取重金属的效率。评估了包括试剂浓度、提取时间、pH 值和液固比在内的控制因素，以确定最佳操作条件。分析了提取前后土壤中重金属形态的分布。使用氢键形式的γ-PGA（200 mM），在洗涤时间为 40 分钟、液固比为 10:1、pH 值为 6 的条件下，一轮和连续提取过程可分别达到 46%和 74%的重金属去除效率。主要的重金属去除机制是：（1）γ-PGA 促进溶解和（2）重金属与γ-PGA 中的游离羧基形成配合物，导致重金属从土壤中解吸。洗涤后土壤中的金属形态重新分布，且土壤修复不会破坏土壤结构和生产力。
