Adsorption mechanism and remediation of heavy metals from soil amended with hyperthermophilic composting products: Exploration of waste utilization.

[Display omitted] • Hyperthermophilic composting products (HP) more effectively adsorb heavy metals. • High content of hydroxyl and carboxyl groups in HP is responsible for adsorption. • HP decreases heavy metals leaching concentration and the risk level in the soil. • HP promotes heavy metal transformation from unstable to stable chemical forms. Due to high humification, hyperthermophilic composting products (HP) show potential for remediating heavy metal pollution. However, the interaction between HP and heavy metals remains unclear. This study investigated the adsorption mechanism and soil remediation effect of HP on heavy metals. The results showed that the maximum adsorption capacity of HP increased by an average of 30.74 % compared to conventional composting products. HP transformed 34.87 % of copper, 42.55 % of zinc, and 35.63 % of lead from exchangeable and reducible forms into residual and oxidizable forms, thus reducing the soil risk level. In conclusion, HP significantly enhanced the adsorption of heavy metals and their transformation from unstable to stable forms, primarily due to the higher content of hydroxyl and carboxyl groups. This study aims to demonstrate the effectiveness of HP for remediating heavy metal pollution and to enhance the understanding of the underlying mechanism, which lays a foundation for waste utilization. [ABSTRACT FROM AUTHOR]