Synergistic effects of peat and MICP for copper tailings remediation: Metal immobilization, nutrient retention, and...

Copper tailings pose a critical environmental challenge due to high heavy metal mobility and extreme ecological barrenness. This study developed a synergistic peat-assisted microbially induced carbonate precipitation (PMICP) technology to address this dual problem. The PMICP strategy leverages peat's multifunctional roles: its organic matter collaborates with MICP-generated carbonates to form an "organo-mineral dual encapsulation" structure for immobilizing copper, while its endogenous microbial consortia act as "ecological engineers" to restructure the community and rebuild nutrient-cycling networks, fostering a diverse and well-balanced microbial assemblage. Compared with raw tailings, PMICP reduced exchangeable Cu, CaCl₂-Cu, DTPA-Cu, and TCLP-Cu by 86 %, 79.5 %, 32.7 %, and 42.0 %, respectively, and enhanced soil fertility by increasing total nitrogen and organic carbon approximately 8-fold. A 12-month field validation confirmed the technology's robustness, reducing plant Cu accumulation by > 70 % while increasing biomass 4.3-fold. Therefore, this work achieves simultaneous contaminant containment and ecological restoration, providing a new paradigm for the sustainable and holistic management of tailings.