Research on Enzyme-induced Soil Heavy Metal Stabilization Mediated by Mineral Materials

<p indent="0mm"> This study selected two low-carbon mineral materials, perlite and diatomaceous earth, as mediators and adopted the enzyme-induced calcium carbonate precipitation (EICP) technology to stabilize and remediate soil heavy metals. The optimal temperature <sc>(30 ℃),</sc> pH value (7-8), calcium source, and proportion of calcium source were determined in this study, at which urease activity reached its peak and the maximum amount of calcium carbonate was generated. Immobilization and remediation of soil heavy metal studies showed that both mediator materials could regulate soil physicochemical properties such as pH and electrical conductivity, and could coordinate with the EICP technology to enhance the mineralization and immobilization of soil heavy metals. Among them, the treatment using perlite as the mediator and calcium chloride as the calcium source showed the optimal results, with the formed calcium carbonate crystals being structurally stable, and having strong ion exchange capacity. Toxicity Characteristic Leaching Procedure (TCLP) toxicity leaching test indicates that the combined technology of mediator-induced enzyme-induced calcium carbonate precipitation has significant stabilizing effects on soil heavy metals and has broad application prospects in soil heavy metal pollution remediation.