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Behaviour and mechanism of cadmium immobilization in contaminated soil by calcium carbide residue-enhanced MICP

Year: 2024
Type: article
Abstract: A novel technique that couples microbially induced calcite precipitation (MICP) and calcium carbide residue (CCR) is proposed for immobilizing Cd 2+ in contaminated soil. The properties and mechanism of CCR-enhanced MICP were investigated through a series of experimental analyses considering factors such as heavy metal concentration, curing time, and the effect of Ca 2+ . The unconfined compressive strength (UCS) increased with increasing curing time and reached a maximum value at 28 d, and the leaching concentration of Cd 2+ decreased and tended to level off with increasing curing time. The addition of CCR enhanced the immobilization performance of Cd 2+ through the MICP method, resulting in UCSs that were 3.8–4.2 times those of samples without CCR and leaching concentrations of Cd 2+ that were 38.9–69.2% lower at a curing time of 28 d. The addition of Ca 2+ to cementation solutions further improved the immobilization effectiveness, resulting in the UCSs of the samples increasing by 18.7–49.8% and the leaching concentrations of Cd 2+ decreasing by 11–40% CaCO 3 and its hydration products can immobilize Cd 2+ through coprecipitation, reducing its toxicity by converting weak acid-extractable cadmium into residual cadmium. Consequently, Sporosarcina pasteurii combined with CCR improved the UCS of the treated contaminated soil and greatly decreased cadmium migration.
DOI: 10.1038/s41598-024-75574-z
Authors: Peng Zhu, Yan Wang, Yuhang Jin, Yang Xiong, Guannian Chen, Fangyi Ruan
Institution: Ningbo University
Language: English
Open Access status: gold
Estimated APC paid: $2,590
OpenAlex ID: W4403761398
FWCI: 1.55
Cites: 52
Cited by: 13
Related to: 10