矿区污染土壤微生物矿化技术分析

Analysis on Microbial Mineralization Technology of Contaminated Soil in Mining Area

有色行业不规范的采选冶过程导致矿区土壤重金属污染严重。生物矿化可以通过生物体自身代谢、细胞或胞外基质将金属离子转变为稳定的固相矿物,是绿色长效的土壤修复技术。其按作用形式主要可分为生物控制矿化和生物诱导矿化。生物控制矿化是通过还原功能菌调整和控制硫化土壤环境中Fe3+浓度,降低土壤环境的氧化还原电位,形成金属硫化矿物沉淀,从而降低重金属的生物有效性和毒性,多用在深层的厌氧环境中。生物诱导矿化则主要通过细胞的生化活动改变周围环境从而实现矿化,目前应用较多的生物诱导碳酸盐沉淀(MICP)主要通过功能菌新陈代谢产生的脲酶催化尿素水解,生成以方解石为主的碳酸盐或复盐晶体,实现重金属的矿化固定,多用在表层或浅层好氧的环境中。

The nonstandard mining, beneficiation and metallurgy process in nonferrous metals industry leads to serious heavy metal pollution in mining soil. Biomineralization can transform metal ions into stable solid minerals through self-metabolism, cell or extracellular matrix, which is a green and long-term soil remediation technology. It can be divided into biological control mineralization and biological induced mineralization. Biocontrol mineralization is to adjust and control the con-centration of Fe3+ in sulfide soil environment by reducing functional bacteria, reduce the redox potential of soil environment, and form metal sulfide mineral precipitation, so as to reduce the bioavailability and toxicity of heavy metals. It is mostly used in deep anaerobic environment. Bioinduced mineralization is mainly through the biochemical activities of cells to change the sur-rounding environment to achieve mineralization. At present, the most widely used microbial in-duced carbonate precipitation (MICP) is mainly through the hydrolysis of urea catalyzed by urease metabolized by functional bacteria to generate calcite-based carbonate or double salt crystals to achieve the mineralization and fixation of heavy metals. It is mostly used in surface or shallow aerobic environment.