Selective adsorption and recycle of Cu²⁺ from aqueous solution by modified sugarcane bagasse under dynamic condition

Tetraethylenepentamine modified sugarcane bagasse was prepared and applied to test its feasibility in removing and recovering Cu²⁺ from wastewater under dynamic condition. Results showed that the Cu²⁺ could be selectively absorbed from wastewater by the modified SCB fixed bed column. To understand the adsorption mechanism, Cd²⁺ had been selected as the model interfering ion to investigate how co-ions influence the adsorption of Cu²⁺ on the sorbent. It was observed that the adsorption capacity of the sorbent for Cu²⁺ (0.26 mmol g^-1) was significantly higher than that of Cd²⁺ (0.03 mmol g^-1), even when the Cd²⁺ initial concentration was 100 times higher than that of Cu²⁺ in the binary system. This finding indicated that the presence of Cd²⁺ in the solution exerted negligible influence on the adsorption of Cu²⁺ on the modified SCB. The selectivity of the modified sorbent was further confirmed in the Cu/Cd/Mg/Pb/K quinary system. Further analysis to dynamic adsorption experiment illustrated that, due to the presence of amine groups, the modified SCB showed strong coordination ability to Cu²⁺, which allowed the other adsorbed ions (e.g., Cd²⁺) desorbed. This high adsorption selectivity toward Cu²⁺ suggested that this prepared sorbent would be a promising candidate for removing and recovering Cu²⁺ from wastewater.