Systematic optimization of biochars derived from corn wastes, pineapple leaf, and sugarcane bagasse for Cu(II) adsorption through response surface methodology

Many industrial wastewaters contain an appreciable amount of toxic copper (Cu(II)) that needs to be properly treated before discharging into receiving water body. Adsorption can effectively remove Cu(II) with optimized parameters. This study investigates the critical pyrolysis parameters of biochar derived from agricultural waste. Optimized biochar showed maximum Cu(II) adsorption capacity of 60.7, 36.8, and 35.5 mg g-1 by PLB, SBB, CWB at pyrolysis temperatures of 555 degrees C, 559 degrees C, 507 degrees C, respectively, compared with commercial activated carbon (CAC, 40.8 mg g-1). Surface characterization confirmed surface complexation, electrostatic interaction, and cation exchange capacity as Cu(II) removal mechanisms. The presence of humic acid reduced the Cu(II) removal of both CAC and optimized biochars. Optimized PLB displayed high reusability (87% Cu(II) removal efficiency) after five consecutive cycles using pressure cooker regeneration. With excellent Cu(II) adsorption