Research Progress of Different Types of Microorganisms Passivation and Fixation of Cadmium Contamination

This is an article in the field of ecological restoration of mines. In recent years, the microbial passivation and fixation has gradually become a hotspot in the field of heavy metal contamination control. Here is a review to summarize the mechanism of microbial passivation and fixation of cadmium based on the passivation and immobilization of typical strains and heavy metal cadmium: (1) Microbial cell walls and extracellular polymers (EPS) have abundant groups, such as carboxyl, hydroxyl, etc., which can effectively adsorb Cd²⁺, and passivated into crystalline minerals. (2) Sulfate-reducingbacteria, phosphate-dissolving bacteria, urease-producing bacteria in the environment can generate metal precipitates through their own metabolism, and then form crystal minerals through changes in the microenvironment. Fe/Mn oxidizing microorganisms indirectly adsorb heavy metal ions through their own metabolites. To study the reaction mechanism of microbial passivation and immobilization of cadmium and the formation of microenvironment conditions of cadmium-containing crystal minerals, which is of great significance for the remediation of cadmium pollution.