Department of Environmental Engineering, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, PR China; Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, PR China.
Department of Civil and Architectural Engineering, Tennessee State University, Nashville, TN, 37209, USA.
Chemosphere. 2022 Jul;298:134213. doi: 10.1016/j.chemosphere.2022.134213. Epub 2022 Mar 10.
In this study, microbial induce carbonate precipitation (MICP) was introduced to immobilize chromium (Cr) in stainless steel pickling sludge (SSPS). Two methods were utilized to conduct the MICP process - Bacteria lysis liquor (BLL)-based MICP and bacteria-based MICP. BLL was obtained by breaking the cell walls with ultrasonic treatment. The urea hydrolyzation test illustrated that the BLL was better than bacteria solution. Both the treatments of bacteria lysis liquor-based MICP and bacteria-based MICP process can effectively entrap the Cr into mineral lattices, that reduce the potential environmental risk of SSPS. With 30 g/L urea and 7 days' treatment, BLL-based MICP presented better immobilization performance than bacteria-based MICP by lowering the bacteria concentration (OD) from 0.8 to 0.7. The excellent biosorption of BLL contributed to Cr removal. Nevertheless, the addition of calcium (Ca) significantly enhanced the immobilization performance of bacteria-based MICP process rather than BLL-based MICP process. pH-dependent leaching tests illustrated the leaching of Cr followed an amphoteric pattern, while the leaching of Ni and Ca followed the cation pattern. Geochemical modeling revealed that the leaching of Cr from bio-mineralized products was solubility-controlled by Cr(OH) and CrO.
在这项研究中，微生物诱导碳酸钙沉淀（MICP）被引入到不锈钢酸洗污泥（SSPS）中以固定铬（Cr）。采用了两种方法来进行 MICP 过程 - 细菌裂解液（BLL）基 MICP 和细菌基 MICP。BLL 是通过超声处理破坏细胞壁获得的。尿素水解试验表明，BLL 优于细菌溶液。细菌裂解液基 MICP 和细菌基 MICP 处理都可以有效地将 Cr 固定在矿物晶格中，降低 SSPS 的潜在环境风险。在 30g/L 尿素和 7 天的处理条件下，BLL 基 MICP 通过将细菌浓度（OD）从 0.8 降低到 0.7，表现出比细菌基 MICP 更好的固定化性能。BLL 的优异生物吸附作用有助于去除 Cr。然而，钙（Ca）的添加显著增强了细菌基 MICP 过程而不是 BLL 基 MICP 过程的固定化性能。pH 依赖性浸出试验表明，Cr 的浸出遵循两性模式，而 Ni 和 Ca 的浸出遵循阳离子模式。地球化学模拟表明，生物矿化产物中 Cr 的浸出受 Cr(OH)和 CrO 的溶解度控制。
