J Environ Sci (China). 2013 Dec 1;25(12):2422-8. doi: 10.1016/s1001-0742(12)60151-x.
Although microbial treatments of heavy metal ions in wastewater have been studied, the removal of these metals through incorporation into carbonate minerals has rarely been reported. To investigate the removal of Fe3+ and Pb2+, two representative metals in wastewater, through the precipitation of carbonate minerals by a microbial flocculant (MBF) produced by Bacillus mucilaginosus. MBF was added to synthetic wastewater containing different Fe3+ and Pb2+ concentrations, and the extent of flocculation was analyzed. CO2 was bubbled into the mixture of MBF and Fe3+/Pb2+ to initiate the reaction. The solid substrates were analyzed via X-ray diffraction, transmission electron microscopy and energy dispersive spectroscopy. The results showed that the removal efficiency decreased and the MBF adsorption capacity for metals increased with increasing heavy metal concentration. In the system containing MBF, metals (Fe3+ and Pb2+), and CO2, the concentrated metals adsorbed onto the MBF combined with the dissolved CO2, resulting in oversaturation of metal carbonate minerals to form iron carbonate and lead carbonates. These results may be used in designing a method in which microbes can be utilized to combine CO2 with wastewater heavy metals to form carbonates, with the aim of mitigating environmental problems.
尽管已经研究了微生物处理废水中重金属离子的方法，但将这些金属通过掺入碳酸盐矿物中去除的方法却很少有报道。本研究采用解淀粉芽孢杆菌（Bacillus mucilaginosus）产生的微生物絮凝剂（MBF），通过碳酸盐矿物的沉淀来去除废水中两种代表性金属（Fe3+ 和 Pb2+）。MBF 被添加到含有不同 Fe3+ 和 Pb2+浓度的合成废水中，并分析絮凝程度。将 CO2 鼓入 MBF 和 Fe3+/Pb2+的混合物中以引发反应。通过 X 射线衍射、透射电子显微镜和能量色散光谱对固体底物进行分析。结果表明，随着重金属浓度的增加，去除效率降低，MBF 对金属的吸附能力增加。在含有 MBF、金属（Fe3+ 和 Pb2+）和 CO2 的系统中，浓缩的金属吸附在 MBF 上并与溶解的 CO2 结合，导致金属碳酸盐矿物过饱和，形成碳酸铁和碳酸铅。这些结果可用于设计一种方法，即利用微生物将 CO2 与废水中的重金属结合形成碳酸盐，以减轻环境问题。
