Application of shrimp shell-derived chitosan for heavy metal biosorption

Growing concern about heavy metal contamination of water resources necessitates the development of effective and sustainable treatment strategies. This study examines the conversion of shrimp shell waste into Chitosan, a biopolymer with exceptional metal adsorption capabilities. The recovered chitosan content was 10.25 ± 0.31%, with an initial chitin concentration of 22.32 ± 0.67% in the raw shrimp shells. A high degree of deacetylation (DD) (90.25±1.81%) significantly enhanced its metal binding efficiency. The structural and functional properties of the synthesized Chitosan were confirmed using fourier transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM-EDX). Adsorption tests were conducted to optimize key parameters, including pH, initial metal content, biosorbent dosage, temperature, and contact time. The adsorption equilibrium was best represented by the isothermal Langmuir model, indicating a monolayer adsorption process on a homogeneous surface. Meanwhile, the kinetic behavior followed a pseudo-second-order model, suggesting that chemosynthesis is the primary mechanism. Chitosan efficiently removed lead and copper from aqueous solutions (20 mg/L), achieving high removal efficiency. These results underscore its potential as a cost-effective and environmentally friendly adsorbent for large-scale water purification and industrial wastewater treatment.