重金属污染的生物矿化治理技术探索

Exploration of biomineralization treatment technology for heavy metal pollution

为探索工程菌生物矿化对重金属污染治理的效果,以野生菌巴氏芽孢八叠球菌(SP)和脲酶工程菌(UE)作为尿素分解菌,通过微生物诱导碳酸盐沉淀(MICP)方法处理含有Cu^(2+),Cd^(2+),Zn^(2+)和Ni^(2+)的单一重金属模拟废水.研究发现:MICP技术对Cu^(2+),Ni^(2+)和Cd^(2+)的去除率较好,均可达到70%以上,其中对Ni^(2+)的去除率可达90%,而对Zn^(2+)的去除率较差(40%).与对照菌相比,脲酶工程菌主要对Cd^(2+)的作用较明显,去除率为野生菌的两倍.扫描电镜观察发现:模拟废水中的重金属离子生物矿化沉淀以菌体和细菌的分泌物作为成核位点,经酸处理分析确认重金属主要是以碳酸盐形式固定.

To explore the effect of biomineralization by engineered strains on the treatment of heavy metal pollution,sporosarcina pasteuri(SP)and urease engineering bacteria(UE)were used as urea decomposing bacteria.Microbially induced carbonate precipitation(MICP)was utilized to treat simulated wastewater containing Cu^(2+),Cd^(2+),Zn^(2+) and Ni^(2+) separately.It is found that the removal rates of Cu^(2+),Ni^(2+) and Cd^(2+) by MICP could reach more than 70%,and the removal rate for Ni^(2+) could reach 90%,while the removal rate for Zn^(2+)(40%)by MICP is worse than others.Compared with the control strain,the UE mainly has obvious effects on Cd,and the removal rate for Cd^(2+) is almost twice the efficiency of SP.The scanning electron microscopy reveals that the nucleation sites of heavy metal ions in simulated wastewater are bacteria and their secretions,and the acid treatment analysis shows that heavy metals are mainly fixed in the form of carbonate.