Mesoporous activated carbon produced from mixed wastes of oil palm frond and palm kernel shell using microwave radiation-assisted K2CO3 activation for methylene blue dye removal: Optimization by response surface methodology

Employing agricultural waste to develop activated carbon through convenient and environment friendly pro-cedures is an excellent approach to conducting green and sustainable development. In this work, a mesoporous activated carbon (hereinafter, abbreviated as OPFPKSAC) was developed by microwave radiation-assisted K2CO3 activation of agricultural wastes including oil palm frond (OPF) and palm kernel shell (PKS). Evaluation of the adsorptive performance of OPFPKSAC was obtained by the removal of a model cationic dye (methylene blue, MB). Box-Behnken design (BBD) was implemented for optimizing the critical adsorption factors including OPFPKSAC dosage, [MB] dye, pH, and time. The BBD model found that the maximum MB removal (99.6 %) occurred under the circumstances of the OPFPKSAC dosage (0.06 g), [MB] dye (10 mg/L), pH (10), and time (20 min). The adsorption equilibrium data is consistent with the Freundlich model, and both the pseudo-first-order and pseudo-second-order models could adequately explain the kinetic data. OPFPKSAC exhibited an outstanding adsorption capability of 331.6 mg/g. Multiple mechanisms like electrostatic forces, pore filling, H-bonding, and 7C-7C stacking, are involved in the MB dye adsorption on the OPFPKSAC's surface. This research demonstrates that the OPFPKSAC, with its environmentally benign synthesizing, low cost, high efficiency, and ease of use, is a promising adsorbent for the removal of toxic pollutants.