Efficiency of talcum-biochars in immobilization of heavy metals and promotion of the growth of Brassica chinensis in contaminated agricultural soil
Haohao Lyu, Kai Cheng, Lili He, Shengmao Yang, Yuxue Liu, Lingcong You, Yuying Wang
Abstract
• Talcum-biochar plays a key role in stabilization of multiple heavy metals. • The soil's heavy metal concentration and plant uptake were impeded. • Talcum-biochar reduced the exchangeable fractions heavy metals in soil. • The soil properties are enhanced by talcum-biochar remediation. • Talcum-biochar could be serve as a cost-effective amendment. Soil contamination with multiple heavy metals poses a significant threat to the global environment. This study aimed to evaluate the ability of a novel talcum-modified biochar as a soil amendment to improve soil properties and remediation performance in agricultural soils contaminated with various heavy metals. Pot experiments were performed in a greenhouse to evaluate the influences of biochar and talcum-modified biochars at 0 %, 0.5 %, 1 %, and 2 % application rates on growth and heavy metal accumulation in Brassica chinensis ( B. chinensis ). The talcum-biochar composites exhibited superior immobilization efficacy for multiple heavy metals compared to pristine biochar. CaCl 2 -heavy metal contents decreased under the treatment with talcum-biochar, in contrast to the control. Sequential extraction procedures revealed that the more accessible forms of heavy metals were converted into less accessible forms. The application of talcum-biochar reduced the Cu, Zn, Cr, and Cd concentrations in B. chinensis , potentially due to a decrease in their bioavailability in the soil. Following the addition of talcum-biochar composites, increases in soil pH, available P and K levels, total N content, and organic matter concentrations were observed. Additionally, a significant enhancement in catalase and urease activities was noted, whereas acid phosphatase activity was inhibited. Therefore, the utilization of talcum-biochar composites as amendments has great potential for enhancing the soil environment and remediating multiple heavy metal-contaminated soils, making it an eco-friendly and cost-effective approach.