Mechanochemical activation of palm kernel shell using the L₉ Taguchi orthogonal array for carbon dioxide adsorption

The problem faced during bio-based activated carbon synthesis is related to its low yield production, which is plausibly due to intricate conventional activation processes, along with utilization of corrosive chemical activator. Therefore, in this study, the activated carbon synthesis from palm kernel shell as starting material has been carried out via a facile solid-solid mixing (mechanochemical) activation. The feasibility and optimization of the high-yielded palm kernel shell activated carbon production has been done via the L₉ Taguchi orthogonal array, whereby the larger-the-better signal to noise (S/N) ratio has been applied to determine the optimum operating conditions. Four parameters have been studied including the activation temperature (600-800 °C), impregnation ratio (1-3:1), activation time (60-120 min), and nitrogen flow rate (300-900 mL/min). Depending on the operating conditions, the activated carbon yield is ranging from 10 to 50 wt.%. Upon optimization, both the pristine precursor and activated carbon at the optimal conditions are characterized in terms of their surface morphology, porosity, and the surface functionalities. In context of carbon dioxide adsorption, the adsorption capacity at an ambient condition is found to be approximately 1.65 mmol/g, which is comparable to the values reported in the literatures.