Methylene Blue Dye Removal from Aqueous Solution Using Activated Carbon Prepared from Corn Cob Stem: Kinetics, Isotherms and Mechanism Studies

In this study, a waste-to-wealth work has been proposed where activated carbon was synthesized from waste corn cob stems and used for methylene blue (MB) dye removal. Corn cob stems activated carbon (CCSAC) had been prepared in microwave technique using H3PO4 as an activating agent where the impregnation ratio of corn cob stems to H3PO4 was 1:4. Then CCSAC characterized by FTIR, BET, XRD, SEM, EDS, and Raman spectroscopy. The CCSAC showed the mesoporous with a good surface area of 54.61 m2/g. Around 150 mg adsorbent dose, 120 min contact time, pH 10, and 10 mg/L initial concentration, 98% of MB dye was eliminated in the aqueous environment. The Langmuir adsorption model gave a higher correlation coefficient of 0.90 and showed an adsorption capability of 129.77 mg/g. Again, the MB dye adsorption on the CCSAC surface was purely a chemical interaction as found from the pseudo-second-order kinetics model (R2 = 0.95). Three types of interaction i.e. pi-pi interaction, pore filling, electrostatic attraction and hydrogen bonding was occurred between MB dye and CCSAC adsorbent respectively. The analysis finding indicated that CCSAC is an effective material for MB adsorption from the aquatic environment.