Oleochemical Waste-Derived Activated Carbon for Adsorptive Desulfurization: A Response Surface Methodology Approach

This study aims to develop a sustainable adsorbent derived from oleochemical waste for effective removal of sulfur from diesel fuel. Glycerin pitch obtained from the oleochemical industry was converted to activated carbon through chemical activation and further modified with phosphorus (AC/P) and iron (AC/Fe) to enhance adsorptive desulfurization (ADS) performance. The prepared adsorbents were characterized by using FESEM-EDX, BET, XRD, and FTIR analyses. Experimental design and optimization were performed by using the Box-Behnken design (BBD) under the response surface methodology (RSM) framework to determine the effects of key parameters. Optimal conditions comprising an adsorbent dosage of 0.3 g, a reaction time of 60 min, an impregnation ratio of 40%, and a calcination temperature of 700 °C resulted in 96% sulfur removal, effectively eliminating sulfur compounds, such as dibenzothiophene (DBT) and 4,6-dimethylbenzothiophene (4,6-DMDBT), and achieving complete desulfurization of Malaysian commercial diesel. The treated diesel showed improved fuel quality, indicating potential benefits for engine performance and emission reduction. The findings demonstrate that oleochemical waste-derived activated carbon, optimized through RSM, is a highly effective and sustainable adsorbent for achieving near-complete sulfur removal from commercial diesel with promising implications for cleaner fuel and enhanced engine performance.