| 碱改性凹凸棒石对土壤中镉化学形态及环境风险的影响 |
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| 引用本文： | 陶玲,仝云龙,余方可,杨万辉,王艺蓉,王丽,任珺.碱改性凹凸棒石对土壤中镉化学形态及环境风险的影响[J].岩矿测试,2022(1):109-119. |
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| 作者姓名： | 陶玲 仝云龙 余方可 杨万辉 王艺蓉 王丽 任珺 |
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| 作者单位： | 甘肃省黄河水环境重点实验室, 兰州交通大学, 甘肃 兰州 730070;兰州交通大学环境与市政工程学院环境生态研究所, 甘肃 兰州 730070;甘肃瀚兴环保科技有限公司, 甘肃 兰州 730070;陕西科技大学环境科学与工程学院, 陕西 西安 710021 |
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| 基金项目： | 甘肃省黄河水环境重点实验室开放基金（21YRWEK007，21YRWEG003）；甘肃省教育厅产业支撑计划项目（2021CYZC-31）；兰州市人才创新创业项目（2021-RC-41） |
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| 摘 要： | 凹凸棒石进行碱改性后性能的提高，为其钝化修复重金属污染土壤提供重要基础。本文采用不同比例的氢氧化钠对凹凸棒石进行改性，利用扫描电镜(SEM)、X射线衍射(XRD)和傅里叶变换红外光谱法(FTIR)分析改性前后凹凸棒石理化特性的变化，并在人工配制的重金属Cd污染土壤上进行钝化实验，研究氢氧化钠改性凹凸棒石对污染土壤中Cd的化学形态变化以及环境风险的影响。结果表明：与对照相比，添加氢氧化钠与凹凸棒石质量比为1∶2的改性材料，土壤pH值显著升高0.85个单位。酸溶态Cd含量显著降低46.25%,残渣态Cd含量显著增加1.99倍；土壤中Cd的风险评价指数和潜在风险指数分别由36.70%和207.90降至20.08%和86.40,有效降低了土壤中Cd的迁移能力和环境风险。SEM、XRD和FTIR分析表明，凹凸棒石经过改性后表面粗糙程度增加，Si—O—Si键等化学键打开，用于吸附重金属的活性位点增加。碱改性凹凸棒石主要通过吸附作用，硅羟基和氢氧根与Cd2+反应生成沉淀来固定土壤Cd,从而达到钝化修复Cd污染土壤的效果。因此碱改性凹凸棒石可对土壤中Cd进行有效钝化，在重金属污染...
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| 关 键 词： | 凹凸棒石 碱改性 镉 化学形态 环境风险 扫描电镜 X射线衍射法 傅里叶变换红外光谱法 |
| 收稿时间： | 2021/8/27 0:00:00 |
| 修稿时间： | 2021/11/10 0:00:00 |
Chemical Speciation and Environmental Risk of Cd in Soil Stabilized with Alkali-modified Attapulgite |
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| TAO Ling,TONG Yun-long,YU Fang-ke,YANG Wan-hui,WANG Yi-rong,WANG Li,REN Jun.Chemical Speciation and Environmental Risk of Cd in Soil Stabilized with Alkali-modified Attapulgite[J].Rock and Mineral Analysis,2022(1):109-119. |
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| Authors: | TAO Ling TONG Yun-long YU Fang-ke YANG Wan-hui WANG Yi-rong WANG Li REN Jun |
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| Institution: | Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou 730070, China;School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China;Gansu Hanxing Environmental Protection Co., Ltd., Lanzhou 730070, China;School of Environmental and Science Engineering, Shaanxi University of Science & Technology, Xi''an 710021, China |
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| Abstract: | BACKGROUND: Heavy metal pollution in soil has been a serious threat to human health and ecological environmental safety. Stabilization remediation has become an important means of remediation of heavy metal contaminated soil due to the high efficiency and low cost. Attapulgite modified by alkali with an improved performance, provides an important basis for its stabilization and remediation of heavy metal contaminated soil.OBJECTIVES: To analyze the changes in physical and chemical properties of attapulgite before and after modification, and to study the effects of attapulgite modified by NaOH on the chemical speciation changes and environmental risks of Cd in contaminated soil, and to explore the stabilization effects of attapulgite modified by NaOH on Cd in the soil.METHODS: Different proportions of NaOH were used to modify attapulgite. The surface characteristics, crystal structure and functional groups of the materials were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Stabilization experiments were carried out on artificially prepared heavy metal Cd contaminated soil to study the effects of NaOH-modified attapulgite on the changes of chemical speciation of Cd and environmental risks in contaminated soil.RESULTS: By adding the modified material with the mass ratio of NaOH to attapulgite of 1:2, the pH value of the soil was significantly increased by 0.85 units. The exchangeable Cd content decreased by 46.28% and the residual Cd content increased by 1.98 times. The risk assessment code (RAC) and potential risk index (PRI) of Cd in soil decreased the most from 36.70% and 207.90 to 20.08% and 86.40, respectively, which effectively reduced the transfer capacity and environmental risk of Cd in soil. According to SEM, XRD and FTIR analyses, after modification, the surface roughness of attapulgite increased, chemical bonds such as Si-O-Si bonds were opened, so active sites for adsorption of heavy metals increased. Attapulgite modified by alkali immobilized Cd mainly through adsorption, and the reaction of silanol and hydroxide with Cd2+ generated precipitate, so as to achieve the effect of stabilizing and repairing Cd contaminated soil.CONCLUSIONS: Alkali-modified attapulgite can effectively stabilize Cd in soil, which has a significant application prospect in remediation of heavy metal contaminated soil. |
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| Keywords: | attapulgite alkali modification cadmium chemical speciations environmental risk scanning electron microscopy X-ray diffraction Fourier transform infrared spectroscopy |
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