College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China; State Key Laboratory for Mineral Deposits Research, Nanjing University, Nanjing, Jiangsu 210046, China.
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
J Hazard Mater. 2018 Sep 5;357:491-497. doi: 10.1016/j.jhazmat.2018.06.032. Epub 2018 Jun 15.
Pb is a toxic heavy metal in contaminated soil and water, resulted from industrial activities, mine exploration, etc. Phosphate solubilizing bacteria are able to secrete organic acids and further to enhance the solubility of phosphates. Enterobacter. sp and geological fluorapatite (FAp) were applied to investigate the biotransformation of Pb in solution with SO, PO, and Cl species by ICP-OES, ATR-IR, XRD, and SEM. Enterobacter. sp can lower pH of the medium to ∼4. Meanwhile, >90% mobile Pb (declining from 1000 to 30 ppm) was immobilized via the combination of Enterobacter. sp and FAp. With the addition of FAp and Pb, pyromorphite was precipitated, but with relatively low content. In contrast, abundant anglesite mineral was formed in such weakly acidic system. These anglesite crystals can even absorb phosphates particles onto their surface. Additionally, geochemical modeling confirms the formation of anglesite and cerussite under weekly acidic and alkalic condition respectively, especially when HPO concentration <10 mM. Furthermore, the presence of Cl in solution leads to the formation of chloropyromorphite when HPO concentration >10 mM, especially under neutral environment. This study explored the biotransformation of Pb in SO-PO-Cl aqueous system and hence provided guidance on bioremediation of Pb by bacteria and FAp.
铅是一种有毒的重金属，存在于受污染的土壤和水中，主要来源于工业活动、采矿勘探等。解磷菌能够分泌有机酸，从而进一步提高磷酸盐的溶解度。本研究采用肠杆菌（Enterobacter. sp）和地质氟磷灰石（FAp），通过电感耦合等离子体发射光谱仪（ICP-OES）、衰减全反射-傅里叶变换红外光谱（ATR-IR）、X 射线衍射（XRD）和扫描电子显微镜（SEM）等手段，研究了溶液中 SO、PO 和 Cl 物种存在时 Pb 的生物转化。肠杆菌能够将培养基的 pH 值降低到约 4。同时，超过 90%的可移动 Pb（从 1000 降至 30 ppm）通过肠杆菌和 FAp 的结合被固定。添加 FAp 和 Pb 后，白铅矿沉淀，但含量相对较低。相比之下，在这种弱酸性体系中形成了大量的硫酸铅矿。这些硫酸铅矿晶体甚至可以将磷酸颗粒吸附到其表面。此外，地球化学模拟证实，在弱酸性和弱碱性条件下分别形成了硫酸铅矿和碳酸铅矿，尤其是当 HPO 浓度 <10 mM 时。此外，当 HPO 浓度 >10 mM 且处于中性环境时，溶液中 Cl 的存在会导致氯代白铅矿的形成。本研究探讨了 SO-PO-Cl 水溶液中 Pb 的生物转化，为细菌和 FAp 修复 Pb 污染提供了指导。
