Chitosan–alunite composite: An effective dye remover with high sorption, regeneration and application potential

• CAC has excellent sorption potential for AR1 and RR2 dyes.
• Sorption of dyes satisfactorily fitted by the Langmuir isotherm.
• The sorption performance of CAC did not decrease for 20 consecutive cycles.
• CAC showed good sorption yields for anionic dyes at real conditions.

This study was undertaken to prepare a novel and environmentally friendly composite for the use in the wastewater treatment process. This composite was produced by immobilizing alunite with a glucosamine biopolymer, chitosan. Batch and dynamic flow mode decolorization potential of the chitosan–alunite composite (CAC) was systematically evaluated in Acid Red 1 (AR1) and Reactive Red 2 (RR2) contaminated media. pH, sorbent dosage, contact time and flow rate were screened through the sorption experiments. Equilibrium sorption experiments indicated that CAC has very high sorption potential for RR2 and AR1 dyes with the maximum sorption capacities of 462.74 and 588.75 mg g−1, respectively. Good regeneration and reuse potential in 20 consecutive cycles are other important advantages of this composite. More importantly, CAC could also be used in the treatment of real wastewater without performance decrease. Overall, this study suggests that CAC is a promising sorbent for the removal of anionic dyes from aqueous solutions.