Cu(II) and Zn(II) removal using eggshell and sugarcane bagasse from synthetic wastewater as new composite adsorbent

Abstract This study develops an affordable and eco-friendly heavy metal adsorption system using eggshell (ES) and sugarcane bagasse (SB) for Cu(II) and Zn(II) removal from synthetic wastewater. Batch adsorption experiments were conducted with varying contact times (20-120 min), adsorbent dosages (0.5-2.5 g/100 ml), and initial concentrations (2 and 5 mg/L). The ES-SB composite achieved over 90% removal efficiency for both metals at optimal dosages of 1.5 g/100 ml for Cu(II) and 2 g/100 ml for Zn(II), with contact times of 100 min and 80 min, respectively. Maximum removal efficiencies were 94% for Cu(II) and 91.4% for Zn(II) at a 5 mg/L concentration. The equilibrium data fit the Freundlich Isotherm model (R 2 = 0.912 for Cu(II) and 0.903 for Zn(II)) and followed Pseudo-Second-Order kinetics (R 2 = 0.9616 for Cu(II) and 0.9991 for Zn(II)). The Sum of Square Error (SSE) analysis confirmed the models’ accuracy. This study highlights ES and SB as promising materials for efficient heavy metal removal from wastewater.