Modeling the removal of Cd(II) and Pb(II) from aqueous solutions by biochar derived from arsenic hyperaccumulator Pteris vittata

Abstract

This study explored the feasibility of utilizing biochar derived from Pteris vittata, an arsenic (As)-hyperaccumulating plant, for cadmium (Cd) and lead (Pb) adsorption. Biochars were produced from P. vittata with high and low As accumulation and compared with biochar derived from uncontaminated corn straw. The results demonstrated that P. vittata biochar exhibited superior adsorption capacity, reaching 98.4 mg/g for Cd(II) and 176 mg/g for Pb(II). Pb(II) adsorption was 38.2 % higher than that of Cd(II), primarily due to Pb(II)'s lower hydration energy and stronger affinity to biochar surfaces. Mechanistic analysis revealed that surface complexation was the dominant adsorption pathway, while As release from P. vittata biochar facilitated additional adsorption sites, creating a synergistic effect that enhanced metal uptake. By integrating geochemical modeling, this study provides novel insights into the interactions between biochar-derived As and heavy metal adsorption. Its findings highlight the potential of P. vittata biochar as an innovative and sustainable material for controlling heavy metal pollution.