Study on the adsorption of malachite green from aqueous solutions using activated carbon prepared from Corallocarpus...

This study explores the preparation and characterization of activated carbon (AC) derived from Corallocarpus epigaeus through sulfuric acid activation for the removal of malachite green (MG) dye from aqueous solutions. X-ray diffraction (XRD) analysis confirmed the amorphous nature of AC, contributing to its enhanced adsorption properties. Brunauer-Emmett-Teller (BET) analysis revealed a mesoporous structure with a specific surface area of 22.976 m²/g, indicating its potential for dye removal. Adsorption experiments were conducted under varying conditions, including initial pH, adsorbent dosage, dye concentration, and co-ion presence. The highest MG removal efficiency was achieved with 100 mg of AC. Adsorption data were well described by Langmuir, Freundlich, Tempkin, D-R, Liu, Redlich-Peterson isotherm models, suggesting a combination of monolayer adsorption and heterogeneous surface interactions. Optimal dye removal occurred under acidic conditions, likely due to electrostatic interactions between the AC surface and MG molecules. The pseudo-second-order equation was best suited for the adsorption data indicating chemisorption. Temperature studies demonstrated increased adsorption efficiency with rising temperature, with equilibrium achieved within 90-160 min. These findings highlight Corallocarpus epigaeus-derived AC as a promising, cost-effective adsorbent for synthetic dye removal from wastewater, with potential scalability for industrial applications.