Biobased Chitosan–Carbon Composite Beads from Azadirachta excelsa for Dual Dye Adsorption

Investigation of adsorption of Congo Red (CR) and Methylene Blue (MB) dyes by chitosan beads (CB) and chitosan carbon based of Azadirachta excelsa composite beads (CAECB) has been carried out. The adsorbent was synthesized with varying mass ratio of chitosan and carbon. The composite was synthesized with PVA as a cross linker agent. This research was carried out in several stages for adsorbent preparation, degree of swelling, the stability of the adsorbent, and the effect of contact time (adsorption kinetics), and isotherm adsorption. The degree of swelling of the adsorbent range from 380–610% and the adsorbent was stabled when soaked using distilled water until the 5th day (0% deformation). The best adsorbent for adsorption of MB and CR are CAECB 0,5 and chitosan beads (CB), respectively. The optimum adsorption time of MB was obtained at 90 minutes with the adsorption percentage of 99.10% by CAECB 0.5. The optimum adsorption time of CR was obtained at 150 minutes with the adsorption percentage of 96.01% by CB. The kinetics result follow pseudo second order rate equation for CAECB 0.5-MB, CB-MB, and CB-KR. The kinetics result for CAECB 0.5-MB was followed pseudo first order rate equation.