School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China.
School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China.
Chemosphere. 2024 Sep;363:142977. doi: 10.1016/j.chemosphere.2024.142977. Epub 2024 Jul 29.
Microbially induced carbonate precipitation (MICP) is a common biomineralization method, which is often used for remediation of heavy metal pollution such as hexavalent chromium (Cr(VI)) in recent years. Calcium sources are essential for the MICP process. This study investigated the potential of MICP technology for Cr(VI) remediation under the influence of three calcium sources (CaCl, Ca(CHCOO), Ca(CHO)). The results indicated that CaCl was the most efficient in the mineralization of Cr(VI), and Ca(CHO) could significantly promote Cr(VI) reduction. The addition of different calcium sources all promoted the urease activity of Sporosarcina saromensis W5, in which the CaCl group showed higher urease activity at the same Ca concentration. Besides, with CaCl, Ca(CHCOO) and Ca(CHO) treatments, the final fraction of Cr species (Cr(VI), reduced Cr(III) and organic Cr(III)-complexes) were mainly converted to the carbonate-bound, cytoplasm and cell membrane state, respectively. Furthermore, the characterization results revealed that three calcium sources could co-precipitate with Cr species to produce CaCrO(CO), and calcite and vaterite were present in the CaCl and Ca(CHCOO) groups, while only calcite was present in the Ca(CHO) group. Overall, this study contributes to the optimization of MICP-mediated remediation of heavy metal contaminated soil. CaCl was the more suitable calcium source than the other two for the application of MICP technology in the Cr(VI) reduction and mineralization.
微生物诱导碳酸钙沉淀（MICP）是一种常见的生物矿化方法，近年来常用于修复六价铬（Cr(VI)）等重金属污染。钙源是 MICP 过程的关键。本研究考察了三种钙源（CaCl、Ca(CHCOO)、Ca(CHO)）对 Cr(VI)修复的 MICP 技术的应用潜力。结果表明，CaCl 在 Cr(VI)矿化中最为有效，而 Ca(CHO)能显著促进 Cr(VI)还原。不同钙源的添加均促进了 Sporosarcina saromensis W5 的脲酶活性，其中相同 Ca 浓度下 CaCl 组的脲酶活性更高。此外，用 CaCl、Ca(CHCOO)和 Ca(CHO)处理后，Cr 形态（Cr(VI)、还原态 Cr(III)和有机 Cr(III)-络合物）的最终形态主要转化为碳酸盐结合态、细胞质和细胞膜态。此外，表征结果表明，三种钙源可以与 Cr 形态共沉淀生成 CaCrO(CO)，在 CaCl 和 Ca(CHCOO)组中存在方解石和文石，而在 Ca(CHO)组中仅存在方解石。总的来说，本研究为优化 MICP 介导的重金属污染土壤修复提供了参考。与其他两种钙源相比，CaCl 更适合用于 MICP 技术在 Cr(VI)还原和矿化中的应用。
