湖北农业科学 ›› 2021, Vol. 60 ›› Issue (20): 72-79.doi: 10.14088/j.cnki.issn0439-8114.2021.20.013

• 资源·环境 • 上一篇    下一篇

EDTA、EDDS和CA对黄土中重金属溶出、解吸及形态的影响

杨明航1, 王国兰1, 金梓涵1, 戴恩华1, 张军1,2   

  1. 1.宝鸡文理学院陕西省灾害监测与机理模拟重点实验室,陕西 宝鸡 721013;
    2.长安大学旱区地下水文与生态效应教育部重点实验室,西安 710064
  • 收稿日期:2021-02-03 出版日期:2021-10-25 发布日期:2021-11-05
  • 通讯作者: 张 军(1974-),男,副教授,博士,主要从事区域重金属污染控制与风险评价,(电子信箱)zhangjun1190@126.com。
  • 作者简介:杨明航(1995-),男,河南安阳人,在读硕士研究生,研究方向为区域重金属污染控制与空间过程,(电话)15139251404(电子信箱)yangminghang1995@163.com。
  • 基金资助:
    国家自然科学基金项目(41771215); 旱区地下水文与生态效应教育部重点实验室(长安大学)开放基金项目(300102290504); 陕西省社会科学界重大理论与现实问题研究项目(2020Z042); 陕西省灾害监测与机理模拟重点实验室项目(20JS012); 陕西省地理学重点学科项目

Effects of EDTA,EDDS and CA on the dissolution,desorption and morphology of heavy metals in loess

YANG Ming-hang1, WANG Guo-lan1, JIN Zi-han1, DAI En-hua1, ZHANG Jun1,2   

  1. 1. Shaanxi Key Laboratory of Disaster Monitoring and Mechanism Simulation,Baoji University of Arts and Sciences,Baoji 721013,Shaanxi,China;
    2. Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of Ministry of Education,Chang’an University,Xi’an 710064,China
  • Received:2021-02-03 Online:2021-10-25 Published:2021-11-05

摘要: 为探究乙二胺四乙酸(EDTA)、乙二胺二琥珀酸(EDDS)与柠檬酸(CA)作用下重金属在黄土中的溶出效应、解吸动力学及其重金属形态变化,采用振荡离心法对比研究3种螯合剂在不同浓度、不同pH、不同时间条件下,对Cd、Cu、Pb、Zn 4种重金属的溶出率、解吸行为和变化特征,并运用动力学模型对解吸过程进行拟合。结果表明,3种螯合剂中EDTA作用效果最为明显,其对4种重金属中Cd的去除率最高;3种螯合剂的浓度在1 mmol/L时,重金属的溶出率达到最高;同时发现pH越低,黄土中重金属溶出率越高,当pH=4时,3种螯合剂对重金属的溶出率均达到最高。在使用螯合剂之后,重金属溶出率增加、解吸率增长,解吸速率随解吸时间的延长而不断降低,前120 min为快速反应阶段。双常数方程是描述黄土中Cd、Cu、Pb、Zn解吸动力学的最佳方程,一级动力学方程拟合效果最差。EDTA、EDDS、CA主要去除对象为重金属水溶态,在EDTA、EDDS和CA的解吸作用下,黄土中的Cd、Cu、Pb、Zn离子总量有效减少,降低了污染土壤的生物毒性。

关键词: 螯合剂, 重金属, 溶出, 动力学模型, 形态

Abstract: In order to study the effects of EDTA, EDDS and CA on the dissolution, desorption kinetics and speciation of heavy metals in loess, the dissolution, desorption behavior and variation characteristics of Cd, Cu, Pb, Zn and four heavy metals by three chelating agents under different concentrations, different pH and different time were studied by vibration centrifugation method, and the desorption process was fitted by kinetic model. The results showed that among the three chelating agents, EDTA had the most significant effect, and its removal rate of Cd was the highest; When the concentration of three chelating agents was 1 mmol/L, the dissolution rate of heavy metals reached the highest; At the same time, the lower the pH was, the higher the dissolution rate of heavy metals in loess was; When pH=4, the three chelating agents had the highest dissolution rate of heavy metals. After the use of chelating agent, the dissolution rate and desorption rate of heavy metals increased, and the desorption rate decreased with the extension of desorption time. The first 120 min was a rapid reaction stage. The double constant equation was the best one to describe the desorption kinetics of Cd, Cu, Pb,and Zn in loess, and the first-order kinetic equation had the worst fitting effect. The main removal objects of EDTA, EDDS and CA were water-soluble heavy metals. Under the desorption of EDTA, EDDS and CA, the total amount of Cd, Cu, Pb, Zn ions in loess could be effectively reduced, which also meant that the biological toxicity of contaminated soil was reduced.

Key words: chelating agent, heavy metal, dissolution, dynamic model, form

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