Removal Of Methylene Blue Dye Using Palm Trunk Based Activated Carbon Via Microwave Irradiated: Optimization, Isotherm, Kinetic And Thermodynamic Studies

Polluting the environment with synthetic dyes can adversely affect humans, animals, and plants. This study aimed to produce optimized palm-trunk-based activated carbon (PTAC) using response surface methodology (RSM) to remove methylene blue (MB) dye. The PTAC was prepared by physical activation with microwave radiation and carbon dioxide (CO2) gasification. The RSM revealed the optimal PTAC preparations with an
activation time of 4 minutes and a radiation power of 501 W, respectively. Optimized PTAC
removed 91.25 % of the MB dye, and the PTAC yield was 32.37 %. The Brunauer- EmmettTeller (BET) surface area of this sample is 772.35 m2 /g, the pore volume is 0.45 cm3 /g, and the fixed carbon content is 74.30 %. The pores created in PTAC is mesopores type of pores, with an average diameter of 3.88 nm. The Freundlich model performed the best on the adsorption isotherm which signified the multilayer coverage of MB occurred on the surface of PTAC. The maximum monolayer adsorption capacity, Qm computed from Langmuir
model was found to be 312.50 mg/g. In terms of kinetic study, the pseudo-second-order (PSO) model performed the best with rate constant, k2 decreased from 0.087 to 0.016 g/mg.h when MB initial concentration increased from 25 to 300 mg/L. The thermodynamic study revealed that the adsorption of MB onto PTAC was endothermic in nature (H° = 34.48 kJ/mol), spontaneous (G° = -5.22 to -8.99 kJ/mol) and governed by physisorption (Ea = 7.33 kJ/mol). Therefore, PTAC showed excellent application in dyes wastewater treatment
systems.