Adsorptive Removal of Malachite Green Dye Using Durian Seed-Based Activated Carbon

Chemically prepared activated carbon derived from durian seed (DSAC) was used as adsorbent to adsorb Malachite green (MG) dye. The prepared DSAC was characterized using Brunauer–Emmet–Teller (BET), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and proximate analysis, respectively. Batch adsorption studies were carried out for the removal of MG dye from aqueous solutions by varying operational parameters like contact time, initial MG dye concentration, solution temperature, and initial solution pH. Maximum dye removal of 97 % was obtained at pH 8. Experimental data were analyzed by eight model equations—Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, Radke–Prausnitz, Sips, Vieth–Sladek, and Brouers–Sotolongo isotherms—and it was found that the Freundlich isotherm model fitted the adsorption data the most. Adsorption rate constants were determined using pseudo-first-order and pseudo-second-order rate equations, Elovich, intraparticle diffusion, and Avrami kinetic model. The results clearly showed that the adsorption of MG dye onto DSAC followed the pseudo-second-order model, and the mechanism of adsorption was controlled both by film diffusion and intraparticle diffusion. Thermodynamic parameters such as ∆G, ∆H, and ∆S were also calculated for the adsorption process. The process was found to be spontaneous and endothermic in nature. This work provided an attractive adsorbent for the removal of MG dye from wastewaters.