Synthesis and Characterization of Chitosan Hydrogel Bioadsorbent Heavy Metals from Vannamei Shrimp Shell Waste

Heavy metal pollution from industrial wastewater is a serious problem for the environment. Adsorption using natural bioadsorbents is a sustainable and eco-friendly method for reducing heavy metal content in wastewater. This study aims to synthesize and characterize chitosan hydrogel as a bioadsorbent from vannamei shrimp shell waste and test its effectiveness in adsorbing heavy metals Cu and Ni. The synthesis process was carried out through the Knorr method to obtain shrimp shell chitosan (SSC) from chitin, which was then crosslinked with Tetraethylenepentamine (TEPA) into hydrogels, with molar ratio variations of TEPA and SSC (0.4; 0.5; 0.6; 0.7). Characterization was performed using FTIR and SEM to observe changes in functional groups and surface morphology. FTIR results showed that the molar ratio of 0.6 resulted in the most optimal formation of amide groups. Meanwhile, SEM results showed that the hydrogel structure at a molar ratio of 0.6 had the largest pore volume a value of 4.66 x 10¹⁰ and the most even pore distribution. Adsorption tests on electroplating industry wastewater showed that chitosan hydrogels were able to remove 99.17% of Cu and 98.77% of Ni, adsorption capacities of 1.071 mg/g and 2.9735 mg/g, respectively.