摘要
重金属污染土壤水洗后细颗粒(粒径<75μm)的处理与处置是目前较为关注的问题。采用硫酸氢钾(KHSO_(4))对重金属Pb、Zn、Cd含量分别超过《土壤环境质量农用地土壤污染风险管控标准(试行)》(GB 15618—2018)限值0.2、1.6、43倍的土壤细颗粒进行淋洗去除实验,考查了淋洗时间、固液比、淋洗温度和淋洗剂浓度对土壤细颗粒中重金属淋洗去除效果的影响。结果表明:随着淋洗时间由5 min升高到720 min、固液比由1∶5(g/mL)降低到1∶20(g/mL)和温度由5℃升高到45℃,土壤细颗粒中Pb、Zn、Cd的去除率分别增加0.7、1.1、1.2倍,2.6、0.8、0.5倍和0.6、0.6、0.1倍;另外,随着KHSO_(4)溶液浓度的提高,对土壤细颗粒中Zn和Cd的去除率均逐渐提高,Pb的去除率在KHSO_(4)溶液浓度为0.5 mol/L时达到最大,而在KHSO_(4)溶液浓度为0.5~1 mol/L时Pb的去除率逐渐降低,这可能是由于SO_(4)^(2-)与Pb^(2+)生成了PbSO_(4)沉淀;KHSO_(4)对土壤细颗粒中不同形态重金属的去除效果依次为可交换态>可还原态>可氧化态>残渣态;淋洗后土壤细颗粒中全钾含量上升,没有SO_(4)2-的残留。
The treatment and disposal of fine particles(particle size below 75μm)in heavy metal-contaminated soil after washing is currently a major concern.This paper uses potassium bisulfate to leach heavy metals in soil fine particles,in which the content of Pb,Zn,Cd is 0.2,1.6,43 times over the limits of Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land(GB 15618-2018)9and investigates the effects of leaching time,solid-liquid ratio,temperature,and concentration o£potassium bisulfate on leaching efficiency of heavy metal in soil fine particles.The results are as follows:the removal rates of Pb,Zn,Cd increase by 0.7,1.1,1.2 times respectively with the leaching time increasing from 5 min to 720 min,by 4.2,2.0,1.1 times with the solid-liquid ratio decreasing from 1:5 to 1 J 20(g/mL)and by 0.6,0.6,0.1 times with the temperature rising from 5℃ to 45℃;in addition,with the increase of potassium bisulfate solution concentration 9 the removal rates of both Zn and Cd increase gradually,and the removal rate of Pb reaches its maximum when the concentration of potassium bisulfate solution is 0.5 mol/L,and then decreases gradually when the concentration increases from 0.5 to 1 mol/L,which may result from the formation of lead sulfate precipitate from SO_(4)^(2-) and Pb^(2+);the order of removal rates of different forms of Pb,Zn,and Cd in soil fine particles by potassium bisulfate leach is:exchangeable state〉reducible state〉oxidizable state>residue state;there is increase of total potassium,and no significant residual SO_(4)-in the soil after leaching.
作者
许端平
冯肖杰
殷宏
薛杨
XU Duanping;FENG Xiaojie;YIN Hong;XUE Yang(School of Environmental Science and Engineering,Liaoning Technical University,Fuxin 1230009 China)
出处
《安全与环境工程》
CAS
CSCD
北大核心
2023年第3期252-259,共8页
Safety and Environmental Engineering
基金
国家重点研发计划项目(2019YFC1803800)。
作者简介
许端平(1961-),男,博士,教授,主要从事环境土壤修复与生态重建方面的研究。E-mail:Xdpl961@sina.com。
