The effect of extracellular polymeric substances on MICP solidifying rare earth slags and stabilizing Th and U.

Autor: Zou CX; College of Energy and Environment, Inner Mongolia University of Science and Technology, Baotou, 014010, China.; School of Civil Engineering, Yancheng Institute of Technology, Yancheng, 224051, China., Sun ZB; College of Energy and Environment, Inner Mongolia University of Science and Technology, Baotou, 014010, China., Wang WD; School of Civil Engineering, Yancheng Institute of Technology, Yancheng, 224051, China. wwdf123@ycit.edu.cn.; Yancheng Institute of Technology, Jiangsu Province Yancheng City Hope Avenue Road 1, Yancheng, China. wwdf123@ycit.edu.cn., Wang T; College of Energy and Environment, Inner Mongolia University of Science and Technology, Baotou, 014010, China.; School of Civil Engineering, Yancheng Institute of Technology, Yancheng, 224051, China., Bo YX; College of Energy and Environment, Inner Mongolia University of Science and Technology, Baotou, 014010, China., Wang Z; College of Energy and Environment, Inner Mongolia University of Science and Technology, Baotou, 014010, China. wz0478@163.com.; Inner Mongolia Autonomous Region, Inner Mongolia University of Science and Technology, Kundoulun District, No. 7, Alding Street, Baotou City, China. wz0478@163.com., Zheng CL; School of Resources and Environmental Engineering, Shanghai Polytechnic University, Shanghai, 201209, China.
Jazyk: angličtina
Zdroj: World journal of microbiology & biotechnology [World J Microbiol Biotechnol] 2024 Jun 05; Vol. 40 (7), pp. 232. Date of Electronic Publication: 2024 Jun 05.
DOI: 10.1007/s11274-024-04015-w
Abstrakt: Microbially induced carbonate precipitation (MICP) has been used to cure rare earth slags (RES) containing radionuclides (e.g. Th and U) and heavy metals with favorable results. However, the role of microbial extracellular polymeric substances (EPS) in MICP curing RES remains unclear. In this study, the EPS of Lysinibacillus sphaericus K-1 was extracted for the experiments of adsorption, inducing calcium carbonate (CaCO 3 ) precipitation and curing of RES. The role of EPS in in MICP curing RES and stabilizing radionuclides and heavy metals was analyzed by evaluating the concentration and morphological distribution of radionuclides and heavy metals, and the compressive strength of the cured body. The results indicate that the adsorption efficiencies of EPS for Th (IV), U (VI), Cu 2+ , Pb 2+ , Zn 2+ , and Cd 2+ were 44.83%, 45.83%, 53.7%, 61.3%, 42.1%, and 77.85%, respectively. The addition of EPS solution resulted in the formation of nanoscale spherical particles on the microorganism surface, which could act as an accumulating skeleton to facilitate the formation of CaCO 3 . After adding 20 mL of EPS solution during the curing process (Treat group), the maximum unconfined compressive strength (UCS) of the cured body reached 1.922 MPa, which was 12.13% higher than the CK group. The contents of exchangeable Th (IV) and U (VI) in the cured bodies of the Treat group decreased by 3.35% and 4.93%, respectively, compared with the CK group. Therefore, EPS enhances the effect of MICP curing RES and reduces the potential environmental problems that may be caused by radionuclides and heavy metals during the long-term sequestration of RES.
(© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)
Databáze: MEDLINE
Externí odkaz: