Gene

Adsorption

Engineering

Ecology

Enterobacter

Bacteria

Biology

Pyrolysis

Raw material

Biochemistry

Environmental remediation

Citrobacter

Food science

Genetics

Biochar

Organic chemistry

Political science

Environmental chemistry

Soil contamination

Contamination

Escherichia coli

Microbial population biology

Amendment

Chemistry

Bacillus cereus

Pulp and paper industry

Cadmium

Journal of Hazardous Materials

This research explored the effect of biochar pyrolyzed from five different materials on U and Cd immobilization in soil. The results showed that all biochars improved the soil properties and microbial metabolic activities, and effectively immobilized U and Cd, especially corn stalk biochar. Subsequently, three strains Bacillus subtilis, Bacillus cereus, and Citrobacter sp. were mixed in a 3:3:2 proportion as a kind of mixed bacteria (MB9) that could adsorb U and Cd effectively. Two types of MB9-loaded biochar were synthesized by physical adsorption and sodium alginate embed method and referred to as AIB and EIB, respectively. MB9-loaded biochar showed superior U and Cd immobilization performance. At 75 d, the highest reduction in the DTPA- extractable U and Cd (69 % and 56 %) was achieved with the 3% AIB amendment. Additionally, compared to the addition of biochar or MB9 alone, AIB was more effective in promoting celery growth and reducing U and Cd accumulation. Finally, the microbial community structure analysis suggested that the relative abundance of Citrobacter genus and Bacillus genus was significantly increased, suggesting that the mixed bacteria MB9 was successfully colonized. These findings may provide a feasible technology for green and cost-effective remediation of heavy metal contamination in farmland soil.

Application of mixed bacteria-loaded biochar to enhance uranium and cadmium immobilization in a co-contaminated soil