Synergistic Bio-Remediation of Rare Earth Mixed Contaminants in Yellow River Basin Soil Using...

The Yellow River Basin, as a crucial water and ecological zone, is threatened by environmental contamination from the Bayan Obo tailings dam located just 13 km away. Based on the Microbial-Induced Calcite Precipitation, this research used a combined approach of bio-mineralization and bio-sorption to bio-remediate the rare earth elements (REEs) and their mixed contaminants. Optimal conditions for soil solidification and stabilization are determined through solution pretests. Comparative analyses of adsorption, mineralization, and their combined processes were conducted in soil experiments. Evaluating using the results of speciation analysis. Following bioremediation, the adsorption-mineralization group involving indigenous bacteria, Bacillus oceanicus, exhibited the best performance. In this group, the average comprehensive reduction in exchangeable forms of Zn, Pb, La, and Ce was 52.02%, which is 2.9 times that of the adsorption group and 1.3 times that of the mineralization group under the same environmental conditions. These results indicate that the biogenic carbonates and isomorphic lattice substitutions generated through the bioption and bio-mineralization process contribute to the solidification/stabilization of REEs and their mixed contaminants. This approach holds significant importance for environmental protection and ecological restoration in the Yellow River Basin, particularly in the middle and lower reaches of the Yellow River.