Agriculture byproduct-derived versatile Cassia fistula seed shell carbon for the removal of acid violet 17 dye from aqueous solution: adsorption kinetics, equilibrium, and mechanism studies

The present study deals with the preparation and characterization of porous activated carbon from Cassia fistula seed shell (CFSS), an agriculture solid waste (byproducts) for the removal synthetic anionic Acid Violet (AV17) dye by batch adsorption technique, and the results were compared with commercial activated carbon (CAC). BET surface area and point zero charge of the CFSSC is 485.5 m²/g and 6.5. The as prepared CFSSC structural and morphological features were confirmed using XRD, FITR, TGA, and SEM analysis. The effect of diverse experimental parameters such as dosage of adsorbent, contact time, initial concentration of AV17 dye, and pH on the removal of dye by adsorption using the adsorbents (CFSSC and CAC) has been studied in room temperature. The Langmuir and Freundlich isotherm models were applied. The adsorption capacities of the CAC and CFSSC on AV17 dye was found to be 290.90 and 132.45 mg/g, respectively. The adsorption kinetics initiates to be first order with respect to intra-particle diffusion as rate determining step. The process of removal of dyes by adsorption on CAC and CFSSC was found to be highly pH dependent. The maximum adsorption observed at pH 2. The result in the present study indicates that CFSSC could be used as a cost-effective alternative adsorbent for the removal of dilute acidic dyes from wastewater instead of CAC.