Investigating chromium Cr(VI) removal using imidazolium based ionic liquid-chitosan composite adsorptive film

In this study, we prepared a novel promising composite adsorptive film of chitosan modified with 1-butyl-3-methylimidazolium acetate (Chitosan-[BMIM][OAc]) to combine the unique features of ionic liquid into the biosorbent to remove Cr(VI) from contaminated water. The film was characterized through Fourier Transform Infrared Radiation (FT-IR) to ensure proper chemical modification. Batch adsorption studies were systematically conducted to study the effect of parameters like pH, adsorbent dosage, contact time, and the initial concentration of Cr(VI) ions as well as evaluate Cr(VI) removal efficiency. The composite adsorptive film exhibited excellent removal efficiency of almost 87% at optimum pH values (3) and adsorbent dosage (2 g/L). Furthermore, the composite film shows fast kinetics by achieving 87% efficiency within 60 min of contact time. A remarkable adsorption capacity of 125.63 mg/g based on Langmuir isotherm has been demonstrated from the results. After adsorption, FT-IR studies investigation revealed the involvement of OH and NH functional groups in adsorption through electrostatic attraction. The environmentally benign adsorbent synthesized from chitosan biopolymer and [BMIM][OAc] can potentially serve as an excellent adsorbent for Cr(VI) removal from water.