Self-regulated immobilization behavior of multiple heavy metals via zeolitization towards a novel hydrothermal technology for soil remediation
Self-regulated immobilization behavior of multiple heavy metals via zeolitization towards a novel hydrothermal technology for soil remediation
复制标题
通过沸石化对多种重金属进行自我调节固定行为，以实现土壤修复的新型水热技术
DOI：
10.1016/j.envres.2022.114726
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发表时间：
2023
影响因子：
8.3
通讯作者：
Zhenzi Jing
中科院分区：
文献类型：
--
作者：
Yafei Zhang;Jing Ma;Jiajun Miao;Liang Yue;Mingzhao Cheng;Yi Li;Zhenzi Jing
土壤修复技术是治理城市重金属污染的有效手段。本文提出了一种将重金属污染土壤水热转化为沸石原位固定重金属的新技术。在一定的Na/Si和Al/Si比条件下，可以水热合成方沸石和钙霞石。在沸石化过程中，形成的沸石可以根据其大小和电荷改变其种类和结构，以容纳土壤中不同的重金属。由于引入了较小尺寸的Cu 2+，方沸石和一些具有小笼状结构的钙霞石可以通过置换Na+形成Cu 2 +-OH和Cu 2 +-O来适应性地包裹Cu 2+。而钙霞石则通过形成Cd ~（2+）-O来包裹较大尺寸的Cd ~（2+）。沸石晶面间距的变化也与其容纳不同重金属的结构变化相对应。浸出结果表明，铜和镉的浸出量分别降低到0.005%和0.05%，表明小笼对小分子重金属的固定效果更好，与分配系数（Kd）的结果一致。pH环境对重金属浸出率的影响很小，进一步证实了沸石对重金属的稳定结构固定。
More efficient soil remediation technologies are highly anticipated to treat large quantities of heavy metal-polluted urban sites nowadays. Herein, a novel hydrothermal technology of converting heavy metal-polluted soils into zeolites for in-situ immobilizing heavy metals was proposed. The zeolites (analcime and cancrinite) could be synthesized hydrothermally with certain Na/Si and Al/Si ratios. The formed zeolites could manage to change their species and structure during zeolitization to accommodate different heavy metals in soil according to their size and charge. Since smaller-size Cu2+was introduced, analcime and some cancrinite possessing small cages could be formed adaptively to immobilize the Cu2+by replacing Na+and forming Cu2+-OH and Cu2+-O. Whereas, cancrinite with large channels managed to form to immobilize the larger-size Cd2+by forming Cd2+-O. Interplanar spacing variation of zeolites also corresponded to their structural change for accommodating different heavy metals. Leaching results showed the amounts of Cu and Cd leached from the synthesized zeolites were reduced to 0.005% and 0.05% respectively, reflecting a more stable immobilization of smaller heavy metals by small cages, in agreement with the results of distribution coefficient (Kd). Negligible effect of pH environment on the leaching rates further confirmed the stable structural immobilization of heavy metals by zeolites.