Preparation of amino-bagasse/metakaolin based geopolymer hybrid microsphere as a low-cost and effective adsorbent for Cu(Ⅱ)

This study focuses on the utilization of an amino-sugarcane bagasse/metakaolin-based geopolymer hybrid microsphere adsorbent (ASB-MGM) for the efficient removal of Cu2+ from aqueous solutions. The influence factors of pH value and adsorbent dosage on the adsorption amount of ASB-MGM were investigated. The BET specific surface area of the microsphere adsorbents enlarged from 18.09 m2/g to 49.16 m2/g with the incorporation of ASB, while reducing the average pore size from 17.59 nm to 7.76 nm. Characterization techniques including FT-IR, XPS, and SEM-EDS confirmed the successful doping of amino groups, enhancing the adsorption efficiency. The adsorption kinetics fitted a pseudo-second-order model with a maximum monolayer adsorption of 248.13 mg/g for Langmuir. Thermodynamic studies revealed that the adsorption process is a spontaneous heat absorption reaction with an increase in system disorder. The ASB-MGM-Cu was effectively regenerated using HCl (with concentration of 0.1 mol/L) and retained good adsorption capacity. The low-cost, eco-friendly synthesis method presented in this study offers a highly efficient approach for industrial-scale removal of Cu2+. Data will be made available on request.