淋洗是修复土壤的一种简单高效的方法,但是对于渗透性系数低的土壤效果不佳。因此,采用电动修复技术强化农田重金属Cd的淋洗(简称电助淋洗),探讨了不同电解液pH控制方法对电助淋洗去除重金属Cd的影响。研究结果表明在电压梯度为1.5 V/cm、间歇通电5 d,每天连续通电8 h条件下,电助淋洗试验Ex1中重金属Cd的去除率为50.87%,比单一淋洗试验组Ex0中重金属Cd的去除率高10%;电动修复技术能强化土壤中孔隙水的流动,加速重金属离子的迁出,提高重金属去除率,有效促进农田土壤重金属Cd的淋洗效果。对比不控制电解液pH的试验Ex1和控制电解液pH的试验Ex2,Ex3,Ex4可知,控制电解液pH能控制土壤pH值,提高重金属Cd的迁移率。综合考虑现场操作等因素,建议采用电极极性切换控制土壤pH值。
Abstract
Leaching is a simple and efficient way of soil restoration, but the effect on soil of low permeability is unsatisfactory. In view of this, electrokinetic remediation was taken to promote the efficiency of leaching of cadmium-contaminated paddy soils , and the influence of electrolyte pH control on the pH value of soil and the removal of heavy metal Cd was discussed in this paper. Results showed that when voltage gradient is 1.5 V/cm, working for five days intermittently and 8 hours every day continuously, the removal efficiency of Cd in electrokinetic leaching(Ex1) reached 50.87%, 10% higher than test Ex0 which was only simple leaching; electrokinetic remediation could strengthen the flow of pore water in the soil, accelerate the migration of Cd2+ in pore water of soil, improve the removal rate of Cd, and effectively promote the leaching effect of Cd in farmland soil. Compared with test Ex1 in which electrolyte pH was uncontrolled, tests Ex2, Ex3, and Ex4 could control the soil’s pH value and improve the mobility efficiency of Cd2+ in pore water of soil. Therefore, when factors such as site operation were considered, polarity switching technology would be a good choice in controlling soil’s pH value.
关键词
农田土壤 /
重金属Cd /
电助淋洗 /
电解液pH控制 /
电极极性切换
Key words
paddy soil /
cadmium /
leaching-electrokinetic /
electrolyte pH control /
polarity switching
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] FALCIGLIA P P, GIUSTRA M G, VAGLIASINDI F G A. Low-temperature Thermal Desorption of Diesel Polluted Soil: Influence of Temperature and Soil Texture on Contaminant Removal Kinetics[J] . Journal of Hazardous Materials, 2011, 185(1):392-400.
[2] YIN C Y, MAHMUD H B, SHAABAN M G. Stabilization/Solidification of Lead-contaminated Soil Using Cement and Rice Husk Ash[J] . Journal of Hazardous Materials, 2006, 137(3):1758-1764.
[3] RUI L, NAN X, WEI S, et al. Rhizosphere Effects of PAH-contaminated Soil Phytoremediation Using a Special Plant Named Fire Phoenix[J] . Science of the Total Environment, 2014, 473/474(3):350-358.
[4] ZHAO N. Research Progress of Microorganism Agents on Saline-alkaline Soil Microbial Remediation[J] . Anhui Agricultural Science Bulletin, 2013,19(2):22-24.
[5] MAKINO T, KAMIYA T, SEKIYA N, et al. Chemical Remediation of Cadmium-contaminated Paddy Soils by Washing with Ferric Chloride: Cd Extraction Mechanism and On-site Verification[C] ∥Australian Society of Soil Science. Proceedings of the 19th World Congress of Soil Science. Brisbane, Queensland, Australia. August 1-6, 2010: 35-38.
[6] JUAN A O, PENG C S, ABOU-SHADY A. Simultaneous Removal of Cadmium from Kaolin and Catholyte during Soil Electrokinetic Remediation[J] . Desalination, 2012, 300(17):1-11.
[7] 胡艳平,徐 政,王 巍,等. 电动修复治理环境中的铬污染研究进展[J] . 稀有金属,2015, 39(10):941-947.
[8] VEEKEN A H M, HAMELERS H V M. Removal of Heavy Metals from Sewage Sludge by Extraction with Organic Acids[J] . Water Science & Technology, 1999, 40(1):129-136.
[9] 陈春乐, 王 果, 王珺玮. 3种中性盐与HCl复合淋洗剂对Cd污染土壤淋洗效果研究[J] . 安全与环境学报, 2014,14(5):205-210.
[10] YEUNG A T, GU Y Y. A Review on Techniques to Enhance Electrochemical Remediation of Contaminated Soils[J] . Journal of Hazardous Materials, 2011, 195(52): 11-29.
[11] ACAR Y B, ALSHAWABKEH A N. Principles of Electrokinetic Remediation[J] . Environmental Science & Technology, 1993, 27(13): 2638-2647.
[12] ZHOU D M, CANG L, DENG C F. Electrokinetic Processes of Chromium in Yellow Brown Soil as Affected by Hydrogen Peroxide[J] . Acta Pedologica Sinica,2005,42(1):59-63.
[13] 胡艳平. 铜冶炼废水污泥电动修复装置与技术研究[D] .北京:北京有色金属研究总院,2015.
[14] EYKHOLT G R, DANIEL D E. Impact of System Chemistry on Electro-osmosis in Contaminated Soil[J] . Journal of Geotechnical Engineering, 1994, 120(5): 797-815.
[15] PAZOS M, SANROM N M A, CAMESELLE C. Improvement in Electrokinetic Remediation of Heavy Metal Spiked Kaolin with the Polarity Exchange Technique[J] . Chemosphere, 2006, 62(5):817-822.
[16] ZHU S, JINPING D U, SUO M. Alkaline Electrolyte Circulation Enhanced Electrokinetic Remediation of Fluorine-contaminated Soils[J] . Ecology & Environmental Sciences, 2009, 18(5):1767-1771.
[17] 肖珊美. 土壤检验技术[M] . 北京:化学工业出版社, 2011.
基金
水利部公益性行业科研专项(201501019);中央级公益性科研院所基本科研业务费项目(CKSF2015014/SH)
PDF(1870 KB)
