Optimization of the Preparation of NaOH-Activated Carbon from Palm Kernel Shells Using Response Surface Methodology
Year: 2026
Type: article
Abstract: Background: Palm kernel shells are lignocellulosic residues with potential as precursors for activated carbon production. However, the adsorption properties of the resulting carbon depend strongly on thermal and chemical preparation conditions. Optimising the combined effects of calcination temperature, calcination time, NaOH concentration, and impregnation time is therefore important for improving iodine adsorption capacity while avoiding unnecessarily severe treatment conditions. Aims: This study aimed to optimise the preparation of activated carbon from palm kernel shells (Elaeis guineensis) by sodium hydroxide (NaOH) activation and to evaluate the effects of calcination and impregnation conditions on the iodine number. Study Design: Response surface methodology, using a four-factor Box–Behnken design with 27 experimental runs, was applied. Place and Duration of Study: The experiments were conducted at the Environmental Sciences Laboratory, Nangui ABROGOUA University, Côte d’Ivoire. Methodology: Four preparation variables were investigated: calcination temperature (400–800 °C), calcination time (1–3 h), NaOH concentration (0.50–4.00 mol/L), and impregnation time (10–38 h). The iodine number was used as the response variable. Experimental data were fitted to a second-order polynomial model and evaluated using analysis of variance. Results: Iodine numbers ranged from 873.10 to 1891.25 mg/g. The quadratic model was highly significant (F = 64.04; p < 0.0001) with R² = 0.9868. Calcination time, NaOH concentration, and impregnation time showed significant linear effects (p < 0.0001), whereas calcination temperature did not (p = 0.2318). The interactions between calcination time and NaOH concentration and between NaOH concentration and impregnation time were highly significant (p < 0.0001). All quadratic terms were significant. The highest iodine number (1891.25 mg/g) was obtained at 400 °C, 3 h calcination, 2.25 mol/L NaOH, and 24 h impregnation. Conclusion: Palm kernel shells are a promising precursor for producing activated carbon with a high iodine adsorption capacity. Response surface methodology effectively revealed the combined influence of thermal and chemical preparation conditions.
Language: English
Subfield: Water Science and Technology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7214101850