Nipa palm shell as a sustainable precursor for synthesizing high-performance activated carbon: Characterization and application for Hg2+ adsorption

Abstract

We used for the first time nipa palm shell (NPS) waste as a renewable precursor to synthesize high-porous activated carbon (AC) via direct NaOH activation and investigated its Hg2+ adsorption properties. The characterization results exhibit the successful conversion of NPS into AC with the optimum impregnation weight ratio of NaOH to NPS of 0.5:1, resulting in a large surface area, pore volume, microporosity, and zeta potential of 1214 m2/g, 0.758 cm3/g, 86.4%, and −39.4 mV, respectively. The adsorptive performance of AC towards Hg2+ at 25 °C in a continuous mode was evaluated. High surface area, strongly negative surface charge, and oxygen-containing functional groups of the optimized AC presented a high Hg2+ adsorption capacity (227.86 mg/g). Element composition analysis confirmed the Hg2+ adsorption onto the AC layer. The findings denote the utility and effectiveness of NPS-based AC due to its favorable functional properties and cationic Hg2+ uptake in aqueous media.