摘要
为研究巯基坡缕石在模拟酸雨作用下对土壤Cd的钝化,该文通过开展室内柱淋滤实验,探究模拟酸雨作用下巯基坡缕石对土壤中Cd的淋溶行为、土壤p H及Cd形态分布的影响。结果表明,0.025%的巯基坡缕石可使土壤中DTPA提取态Cd浓度降低40.49%,且不改变土壤的p H值。在模拟酸雨的淋出液体积为1200 m L(600 mm降雨量)时,对照组(CK)和巯基坡缕石处理组(MPAL)中Cd累积淋出率分别为18.67%和12.60%(pH 5.6)、18.56%和11.62%(pH 4.5)、19.34%和9.67%(pH 3.0);土柱淋出液和淋滤后土壤的pH值分别升高1~2和0.1~0.3个pH单位,淋出液的EC值逐渐降低,在淋出液体积为500 mL(250 mm降雨量)后稳定,同时巯基坡缕石处理组和对照组之间无显著性差异。淋滤后巯基坡缕石处理组土壤中的全Cd浓度高于对照组,DTPA提取态Cd浓度低于对照组,且在不同土层之间存在差异。模拟酸雨淋滤后,与对照酸雨(CK-pH 5.6)相比,典型酸雨(CK-pH 4.5)和强酸雨(CK-pH 3.0)淋滤后土壤中的DTPA可提取态Cd浓度和可交换态Cd含量分别升高5.94%和31.91%、12.64%和39.30%,增加Cd在土壤中的迁移能力。与对照组相比,巯基坡缕石处理组土壤中可交换态和碳酸盐结合态Cd含量分别降低16.77%和25.13%(MPAL-pH 5.6)、14.73%和23.60%(MPAL-pH 4.5)、1.97%和25.51%(MPAL-pH 3.0),铁锰氧化物结合态和有机结合态Cd含量分别升高57.86%和26.52%(MPAL-pH 5.6)、69.36%和44.23%(MPAL-pH 4.5)、67.70%和53.83%(MPAL-pH 3.0),在酸雨作用下巯基坡缕石可增加土壤中Cd的稳定形态,降低Cd的迁移能力。研究表明:巯基坡缕石在模拟酸雨作用下钝化土壤Cd的效果比较稳定,是一种在南方酸雨区具有良好应用潜力的钝化材料。
In order to study the remediation effect of mercapto-palygorskite(MPAL)on Cd under simulated acid rain,column leaching experiments were conducted to investigate the effects of MPAL on the leaching behavior of Cd,soil p H and heavy metals fractions.The results showed that 0.025%MPAL could reduce 40.49%DTPA extractable Cd and did no affect soil pH value.Under simulated acid rain,the leaching efficiency of Cd in control(CK)and MPAL treatments at 1200 mL leachate volume(600 mm rainfall)were 18.67%and 12.60%(pH 5.6),18.56%and 11.62%(pH 4.5),19.34%and 9.67%(pH3.0),respectively.The pH values of leachate and soil increased by 1~2 and 0.1~0.3 pH unit,respectively;the EC value of leachate decreased with the increasing of leachate volume and stabled at 500 mL leachate(250 mm rainfall),and there was no significant difference between control and treatments.After column leaching,the concentration of total Cd was higher than that in the control,while the concentration of DTPA extractable Cd was lower than that in the control,and existed differences in different soil depth.After column leaching,compared with the normal acid rain(pH 5.6),the concentrations of DTPA extractable Cd and exchangeable Cd in typical(CK-pH 4.5)and strong acid rain(CK-pH 3.0)treatments increased by 5.94%and 31.91%,12.64%and 39.30%,respectively;and increased Cd migration in the soil.Compared with the control,the concentrations of exchangeable Cd and carbonate-bound Cd in MPAL treatments reduced by 16.77%and 25.13%(MPAL-pH 5.6),14.73%and 23.60%(MPAL-pH 4.5),1.97%and 25.51%(MPAL-pH 3.0),respectively;and the Fe/Mn oxide-bound Cd and organic matter-bound Cd in MPAL treatments increased by 57.86%and 26.52%(MPAL-pH 5.6),69.36%and 44.23%(MPAL-pH 4.5),67.70%and 53.83%(MPAL-pH 3.0),respectively;and MPAL increased the stability of Cd in soil and reduced Cd migration under simulated acid rain.The results revealed that the remediation effect of MPAL on Cd was stable under simulated acid rain,and MPAL is a remediation material with good application potential in southern acid region of China.
作者
王雅乐
徐应明
秦旭
黄青青
赵立杰
彭云英
WANG Yale;XU Yingming;QIN Xu;HUANG Qingqing;ZHAO Lijie;PENG Yunying(Agro-environmental Protection Institute,Ministry of Agriculture and Rural Affairs,Tianjin 300191,China;Key Laboratory of Original Agro-environmental Pollution Prevention and Control,Ministry of Agriculture and Rural Affairs,Tianjin 300191,China)
出处
《环境科学与技术》
CAS
CSCD
北大核心
2020年第2期33-40,共8页
Environmental Science & Technology
基金
中国农业科学院创新工程项目(CAASCXGC-xym-2018)
国家现代农业产业技术体系项目(CARS-03-25)。
关键词
酸雨
巯基坡缕石
土柱淋滤
CD
钝化
acid rain
mercapto-palygorskite
column leaching
cadmium
immobilization
