Adsorption Kinetic Studies for the Removal of Synthetic Dye Using Durian Seed Activated Carbon

In this study, durian seeds were chemically modified using KOH as an impregnating agent to prepare durian seed activated carbon (DSAC). DSAC was characterized using FTIR, BET, SEM, and proximate analysis techniques and used for the adsorption of Remazol brilliant blue reactive (RBBR) dye. The effects of pH, contact time, initial dye concentrations, and solution temperature on the adsorption process were investigated experimentally in batch process. Maximum dye removal was obtained at pH 2 to be 95.17%. Experimental data were analyzed using eight model equations: Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Radke-Prausnite, Sips, Viet-Sladek, and Brouers-Sotolongo isotherms and it was found that the Freundlich isotherm model fitted the adsorption data most. Adsorption rate constants were determined using pseudo first-order, pseudo second-order rate equation, Elovich, and Avrami kinetic models. The adsorption of RBBR dye onto DSAC followed pseudo second-order model and the mechanism of adsorption was controlled by both film and Intraparticle diffusions. Thermodynamic parameters such as Delta G, Delta H, and Delta S were also calculated for the adsorption process. The process was found to be spontaneous and endothermic in nature. The results indicate that DSAC is a suitable adsorbent for the adsorption of RBBR dye from aqueous solutions.