Biologically produced sulfur as a novel adsorbent to remove Cd2+ from aqueous solutions

Biological desulfurization processes of landfill gas yield an enormous amount biologically produced S (BPS) as a byproduct. Capability BPS to remove Cd2+ from aqueous solutions was tested and its removal efficiency compared that granular activated carbon (GAC). Kinetics by two-stage process with initial rapid adsorption showing 45% removed within 5 min, followed slower adsorption. Cadmium onto the fitted Langmuir isotherm model maximum capacity (63.3 mg g−1) 1.8 times higher than GAC (36.1 g−1). Thermodynamic parameters showed favorable endothermic. Data XPS proved main mechanism be complexation sulfides in BPS. Results demonstrated can recycled novel adsorbent for wastewater.