Removal of pollutants from aquaculture wastewater using chitosan/bentonite composites beads

Aquaculture systems produce ammonia nitrogen as a byproduct of aquatic animal protein metabolism. The dropwise method is used in this study to prepare composite beads based on chitosan biopolymer and bentonite clay to remove ammonia nitrogen from aquaculture wastewater. The composite beads were characterized using FTIR, XPS, BET, and ESEM. According to the FTIR analysis, CS was successfully immobilized on the surface of Bt. Furthermore, the XPS analysis revealed that the surface chemical of the chitosan/bentonite composite was rich in chitosan elements. To remove ammonia nitrogen, three samples of aquaculture effluents were collected and characterized in terms of physicochemical and chemical aspects. The ammonia nitrogen removal from aquaculture effluents was 100, 91.8, and 87.7% for initial concentrations of 0.56, 1.72, and 2.13 mg/L, respectively. Ammonia nitrogen sorption tends to reach equilibrium in approximately 120 minutes. The findings also show that the kinetic data was well correlated with the pseudo-second-order equation; pH values increased slightly after adsorption, and the same trend was observed for total hardness and alkalinity. As a result, the CSBt composite is a promising adsorbent for ammonia nitrogen removal from aquaculture effluents.