Sustainable Biomass-derived Activated Carbons for the Adsorptive Removal of Alizarin Cyanine Green Dye: Isotherm, Kinetic and Comparative Performance with Commercial Activated Carbon

Abstract

Activated carbons derived from four fruit peel wastes—Soursop Fruit Peel Carbon (SFPC) and Wild Jack Fruit Peel Carbon (WFPC)—were synthesized and evaluated as sustainable adsorbents for the removal of Alizarin Cyanine Green dye from aqueous solutions. The physicochemical characteristics of the prepared carbons were examined. XRD analysis indicated the presence of graphite-like amorphous structures. FTIR spectra confirmed the presence of various surface functional groups, including C = C, C = O, C–H, C–C, and C–O. TGA-DTA and SEM confirming their thermal stability with well-developed porous surface texture. Batch adsorption experiments were performed to investigate the influence of operational parameters on dye uptake. The Langmuir isotherm model provided the best fit for the equilibrium data, indicating a maximum adsorption capacity of 576.92, 398.60 and 389.36mgg-1 for CAC, SFPC and WFPC. Kinetic analyses revealed that dye adsorption followed the pseudo-second-order model, suggesting chemisorption as the dominant mechanism. These findings demonstrate that widely available and low-cost fruit peel wastes can serve as effective, environmentally friendly, and sustainable precursors for the production of activated carbon towards environmental sustainability.