Comprehending the interaction between chitosan and ionic liquid for the adsorption of palladium

Biopolymers and ionic liquids are of prime importance in numerous applications. Recovery of industrially important noble metals such as palladium is of paramount significance considering their diverse applications. The main idea behind this work was to develop an effective strategy involving the impregnation of Aliquat-336 (ionic liquid) onto chitosan as a novel adsorbent for the adsorption of Pd(II). The analytical characterization was systematically done through FT-IR, XRD, SEM and EDX analysis. The interaction of the amino and hydroxyl functional groups in chitosan with the cationic nitrogen in the ionic liquid could be established through the above characterization. Several key parameters such as pH influence, amount of adsorbent, isotherms, kinetics and thermodynamic studies were also studied in detail for the adsorption of palladium. The effectiveness of adsorption was observed between pH 3.5-4.0 with 50 mL of 120 mg L−1 Pd(II) solution giving a commendable monolayer adsorption capacity of 187.61 mg g−1.