Chitosan augmented activated charcoal for adsorption of reactive red 21 dye from solution phase

Abstract

Polymers have been proven to be an interesting class of adsorbents applied in water treatment. Biopolymers are of special interest due to their unique properties such as biocompatibility, biodegradability, and reusability. This work reports a composite formed by a chitosan biopolymer and activated charcoal using sodium citrate as a crosslinking agent. The chitosan–citrate-activated charcoal composite (CAC) was characterized using FT–IR, SEM, EDAX, XRD, TGA–DTA and BET surface area analysis. The material was found to be microporous in nature with a surface area of 165.83 m²/g that led to high adsorption capacities toward the targeted pollutant. In an aqueous phase, the dye adsorption studies were carried out with reactive 21 (R-21) dye. Under optimum solution conditions, maximum Reactive Red (R-21) dye removal capacity was found to be 40.12 mg g⁻¹. Intrinsic microporosity of CAC resulted in an enhanced capture capacity for Reactive Red (R-21) dye. Material sustainability studies were carried out to evaluate various sustainability parameters.