Optimized synthesis of activated carbon from date palm seeds for efficient crude oil adsorption in wastewater treatment.

The effective treatment of oil-contaminated wastewater is a critical environmental challenge. This study demonstrates a robust pathway for synthesizing high-performance activated carbon (AC) from date palm seed waste for the removal of crude oil. A two-step process involving pyrolysis and subsequent KOH chemical activation was systematically optimized by varying key parameters, including temperature, time, and impregnation ratio. The optimized adsorbent, AC5 (prepared at a 4:1 KOH: biochar ratio, 700 °C, for 2 h), exhibited a high surface area of 2151 m²/g and an exceptional crude oil adsorption capacity of 1816 mg/g. A key finding is that maximum surface area alone does not dictate performance for complex adsorbates; AC5 significantly outperformed a sample with a higher surface area (2417 m²/g), a result attributed to its more favorable surface chemistry as confirmed by FTIR analysis. The adsorption process was best described by the Freundlich isotherm and pseudo-second-order kinetic models. Crucially, the performance of the optimized AC represents an improvement of nearly an order of magnitude over previously reported date-seed carbons for oil removal and surpasses that of many other biomass-derived adsorbents. This work establishes a clear synthesis pathway for valorizing an abundant agricultural waste into a superior adsorbent for oil spill remediation.