Characteristics of Calcined Sugarcane Bagasse and Its Ability to Adsorb Cadmium from Aqueous Solutions

This study evaluated the cadmium (Cd) adsorption characteristics of sugarcane bagasse (BG) calcined at different temperatures (200-1000°C). The point of zero charge (pH_pzc) of the BGs ranged from 4.3 to 6.5. The amount of Cd adsorbed was higher at pH 4-8 than at pH 2. These results indicate that the negative charge on the BG surface and the presence of Cd(II) cations are important for Cd adsorption. Meanwhile, the amount of Cd adsorbed and the specific surface area (SSA) of BG increased with increasing calcination temperature of BG. Furthermore, a partial correlation analysis revealed that acidic surface functional groups (SFGs) were also significantly associated with Cd adsorption, independently of SSA. These results suggest that both SSA and acidic SFGs jointly contribute to Cd adsorption.