基于纳米羟基磷灰石的矿化技术修复铅污染水和一维土柱的试验研究

Experimental study on remediation of lead-contaminated water and one-dimensional soil column by mineralization technology based on nano-hydroxyapatite

重金属污染是世界性的环境问题,对人类健康和生态系统都有严重的潜在影响。微生物诱导碳酸盐沉淀(MICP)和酶诱导碳酸盐沉淀(EICP)是环境岩土修复铅污染的重要技术,但2种技术在高浓度铅污染中固化效率较低。文章探究纳米羟基磷灰石协同MICP和EICP技术(MICP-nHAP和EICP-nHAP)修复高浓度铅污染水和黄土的潜力,并对固化效率和强化机理进行深入分析。结果表明:在纳米羟基磷灰石协同作用下,MICP与EICP固化效率明显提高,且产生更稳定的矿化产物碳酸磷酸铅(Pb_(10)(PO_(4))6CO_(3))。将该技术应用于铅污染黄土中,土中可交换态Pb明显降低,MICP-nHAP和EICP-nHAP技术修复后赋存形态以铁锰氧化态Pb为主,相较MICP与EICP技术修复后的碳酸盐结合态Pb具有更高的化学稳定性和更低的生态毒性。因此,纳米羟基磷灰石协同MICP与EICP技术具有广阔的应用前景,研究结果可为修复高浓度铅污染水和黄土提供参考。

Heavy metal pollution is a global environmental issue that poses serious risks to human health and surrounding environments.Microbially Induced Carbonate Precipitation(MICP)and EnzymeInduced CarbonatePrecipitation(EICP)arepopular biomineralization technologies applied to remediation of lead-contaminated soil and water.However,both MICP and EICP suffer from low efficiency when subjected to high lead concentrations.In this study,the potential of applying the nano-hydroxyapatite-assisted MICP and EICP technologies(MICP-nHAP andEICP-nHAP)to remediationoflead-contaminated water and loess was investigated.Results showed that the immobilization efficiency was notably improved by MICP-nHAP and EICP-nHAP,and more stable lead-related phosphate precipitates(Pb_(10)(PO_(4))_(6)CO_(3))wereformed.Resultsalsoindicatedthat under MICP-nHAP and EICP-nHAP,the exchangeable Pb was transformed to the iron and manganese oxidized Pb,presenting higher chemical stability and lower ecotoxicity compared to the carbonate-bound Pb under MICP and EICP.The findings provide a strong piece of evidence supporting a potential of applying MICP-nHAP and EICP-nHAP to remediation of lead-contaminated water and loess site.