Zou Zeli, Qiu Rongliang, Zhang Weihua, Dong Hanying, Zhao Zhihao, Zhang Tao, Wei Xiange, Cai Xinde
School of Environmental Science and Engineering, Sun Yat-sen University, 135 Xin Gang Xi Road, Guangzhou 510275, China.
Environ Pollut. 2009 Jan;157(1):229-36. doi: 10.1016/j.envpol.2008.07.009. Epub 2008 Sep 6.
This study discusses the operating variables for removal of metals from soils using EDTA, including the type of EDTA, reaction time, solution pH, dose, temperature, agitation, ultrasound and number of extractions. For As, Cd, Cu, Pb and Zn, the removal efficiency order was: H(4)-EDTA > Na(2)EDTA > (NH(4))(2)EDTA. At low EDTA concentrations the removal increased progressively with increasing dose while above 0.4 mmol/g only small increases in extraction efficiency were observed. EDTA induced a two-step process including a rapid desorption within the first hour, and a gradual release in the following hours. The extraction efficiency of metals decreased with increasing pH in the range of 2-10. Consecutive extractions using low concentrations were more effective than a single extraction with concentrated EDTA if the same dose of EDTA was used.
本研究探讨了使用乙二胺四乙酸（EDTA）从土壤中去除金属的操作变量，包括EDTA的类型、反应时间、溶液pH值、剂量、温度、搅拌、超声以及萃取次数。对于砷、镉、铜、铅和锌，去除效率顺序为：H(4)-EDTA > Na(2)EDTA > (NH(4))(2)EDTA。在低EDTA浓度下，去除率随剂量增加而逐渐提高，而在高于0.4 mmol/g时，仅观察到萃取效率有小幅增加。EDTA引发了一个两步过程，包括在第一小时内的快速解吸以及在随后几小时内的逐渐释放。在2至10的pH范围内，金属的萃取效率随pH升高而降低。如果使用相同剂量的EDTA，连续使用低浓度萃取比单次使用高浓度EDTA萃取更有效。
