微生物成矿技术在环境砷污染治理中的应用研究进展

Advancement of Research on Application of Microbial Mineralization Technology in Remediation of Arsenic Contaminated Environment

近年来,微生物成矿技术成为环境污染治理领域研究热点之一。结合典型矿化菌与砷的成矿关联规律对微生物成矿作用固定砷的机制及环境污染治理中的应用进行归纳:(1)环境中的碳酸盐矿化菌、铁锰氧化菌及硫酸盐还原菌可通过诱导成矿的方式,直接促进含砷矿物的形成或生成其他矿物间接吸附砷,通过对砷的成矿产物和成矿因素分析,揭示微生物成矿机理、特征及形成条件;(2)总结了国内外应用微生物成矿技术处理水体和土壤中砷污染的研究,利用微生物成矿技术可降低水体及土壤中溶解性或可提取态砷浓度、减少砷的生物可利用性;(3)微生物对重金属的成矿作用受环境因素影响,环境中砷的初始浓度、共存金属离子、pH、温度、营养盐浓度等均会影响微生物成矿的效率。加强微生物成矿过程微界面反应机制研究,并筛选重金属耐性和成矿能力强的微生物以提高成矿效率,同时研究成矿作用固定的砷在环境中的溶出和迁移规律进而减少矿物中砷的再次溶出,将成为未来该领域的重点研究方向之一。

In recent years,application of the technology of microbial mineralization has become one of the research hotspots in the field of environmental pollution control.Application of the technology of microbial mineralization has an excellent potential to remove arsenic from water and reduce arsenic bioavailability in soil.Here is a review to summarize mechanisms of the technology of microbial arsenic mineralization and applications of the technology in remediation of arsenic contaminated environments based on the relationship between typical mineralizing bacteria and arsenic mineralization:(1)Carbonate mineralizing bacteria,Fe/Mn oxidizing bacteria and sulfate reducing bacteria in the environment can directly promote formation of arsenic containing minerals or generation of some minerals capable of adsorbing arsenic.Mechanisms,characteristics and formation conditions of the microbial mineralization were explored,through analysis of products and factors of the arsenic mineralization.Microbial induced carbonate precipitation(MICP)can remove As from water or soil solution through adsorption or coprecipitation.Iron-oxidizing bacteria(FeOB)can oxidize Fe(II)into Fe(III)and induce formation of iron oxide and other minerals that adsorb As or reaction of arsenate with Fe(III)to form scorodite(FeAsO4·2H2O).Manganese-oxidizing bacteria(MnOB)can remove As in a similar way as FeOB do.Under sulfate reducing conditions,arsenic can be removed from water through precipitating in orpiment-like phase(As2S3),realgar-like phase(AsS)or arsenopyrite-like phase(FeAsS)with the presence of sulfate reducing bacteria(SRB).Alternatively,arsenic can be removed through being adsorbed in biogenic mackinawite-like phase(FeS),greigite-like phase(Fe3S4)and pyrite-like phase(FeS2)in the presence of iron;(2)Researches at home and abroad on application of the microbial mineralization technology to treating arsenic contamination of water and soil are summarized.The technology can reduce solubility or concentration of extractable arsenic in water and soil and subsequently increase As concentration markedly in the mineral fractions therein after bioremediation;(3)Initial As concentration,coexisting metal ions,pH,temperature and nutrient concentration can affect efficiency of the microbial mineralization.Microbial mineralization is a potential technology to treat arsenic pollution in the environment.However,further studies need to be done as to how to effectively apply the technology to actual treatment of arsenic pollution.And further efforts need to be devoted to exploration of more stable methods to prevent arsenic dissolution from minerals,and development of theories of the application of the microbial mineralization technology to environmental pollution control in combination with practical problems.