摘要
该文在引入外源Si2+、Ca2+和Mg2+条件下,将混维凹凸棒石水热改性为新型凹凸棒石钝化材料(PSMC),用扫描电镜、X射线衍射和傅立叶红外光谱对其进行了表征,通过钝化试验探究了其对矿区土壤中重金属的钝化效果.结果表明,水热处理能使凹凸棒石及其伴生矿物转变为具有晶体结构缺陷的无定形或低结晶硅酸盐.土壤中Cd、Pb、Cu和Zn的二乙烯三胺五乙酸提取态含量在所有PSMC添加处理下均显著降低,且均在5％(w/w)的添加处理下达到最小;添加PSMC促使酸溶态的Cd、Pb、Cu和Zn向更加稳定的残渣态转化;5％的PSMC添加处理下,Cd、Pb、Cu和Zn的钝化效率分别为91.15％、84.70％、90.51％和90.09％.根据土壤管控标准风险等级,重金属的总体污染潜在风险指数随着PSMC添加量的增加而减小,Pb、Cu和Zn的环境风险指数均小于1％,Cd的的环境风险指数均小于3％(低风险).水热改性能提高混维凹凸棒石对矿区土壤中重金属的钝化能力,进而为甘肃混维ATP黏土高值化利用提供新思路、新方法.
Abstract
With the introduction of exogenous Si2+,Ca2+and Mg2+to low-grade mixed-dimensional attapulgite(ATP),the authors prepared the high-grade ATP(PSMC)at laboratory scale using hydro-thermal modification method,which was further characterized using scanning electron microscopy,X-ray diffraction,and Fourier infrared spectroscopy.The deactiva-tion effect of ATP and PSMC on heavy metals in a mining area-neighboring farmland soils was evaluated through the passiv-ation tests,and the result indicated that the hydrothermal modification could cause ATP and its associated minerals turning into the amorphous that was of defective crystal structure or low-crystalline crystallinity.Besides,the addition of PSMC significantly reduced DTPA extractable Cd,Pb,Cu and Zn in soil,and as addition of PSMC was 5％(w/w)the reduction tend-ed minimized;and the addition of PSMC led to the transformation of acid-soluble Cd,Pb,Cu and Zn to the residual fraction that was much more stable.In particular,the deactivation efficiencies of Cd,Pb,Cu and Zn could be up to 91.15％,84.70％,90.51％and 90.09％,respectively when 5％PSMC was addied.Consequently,the potential environmental risk index of heavy metals decreased with the increase of PSMC application amount:according to the risk grade of the relevent soil management and control standard,the indexes of Pb,Cu,and Zn were all below 1％while Cd was well below 3％.Therefore,hydrothermal modification greatly enhances the heavy-metal deactivation capacity of ATP,thus providing an alternative approach for the high-value utilization of low-grade ATP.
基金项目
甘肃省教育厅产业支撑计划项目(2021CYZC-31)
宁夏回族自治区自然科学基金项目(2023AAC03336)
甘肃省科技厅科技计划项目(22CX3GA076)
兰州市人才创新创业项目(2021-RC-41)
宁夏普通本科高校本科教育教学改革研究与实践项目(bjg2023083)
宁夏师范学院本科教学项目(NJZZYGGK2401)
维普
万方数据