Microwave assisted preparation of n-butylacrylate grafted chitosan and its application for Cr(VI) adsorption

Biopolymers such as chitosan possess excellent properties suited for varied applications. In this work, we describe a novel microwave assisted method for the preparation of n-butylacrylate grafted chitosan adsorbent and its utility for the adsorption of chromium(VI). A 3 min irradiation time was enough to prepare the adsorbent, and techniques such as FT-IR, powder XRD, SEM and EDS were used for comprehensive characterization. The adsorption was effective at pH 3.5 with 25 mL of 20 ppm Cr(VI) solution. Langmuir, Freundlich, Dubinin–Radushkevich, Temkin, Elovich and Redlich isotherms were studied in detail. The ΔG, ΔH and ΔS parameters were evaluated to understand the adsorption thermodynamics. The adsorption involves the interaction of Cr(VI) with the hydroxyl and amino groups in chitosan.