Purifying seawater before desalination treatments from oil spills utilizing date palm frond activated carbon

Oil pollution in seawater represents a major challenge for desalination operations, as petroleum-derived contaminants can impair membrane performance and reduce produced-water quality. This study proposes a pretreatment approach using activated carbon derived from date palm fronds to remove petroleum-derived engine-oil contamination from laboratory-prepared simulated seawater before desalination. Simulated seawater was prepared by mixing engine oil with saline solution, and activated carbon was produced by chemical activation of date palm fronds at 700 °C using chromic acid. The resulting activated carbon was characterized using BET surface area analysis, pore-volume and pore-size measurements, zeta potential, SEM, and FTIR analyses. The selected activated carbon sample exhibited a BET surface area of 450.35 m 2 /g, pore volume of 6.81 cm 3 /g, and average pore size of 17.52 nm. Batch and fixed-bed column experiments were conducted to evaluate adsorption performance under different operating conditions. The highest adsorption capacity of 117 mg/g was achieved at pH 8.5 within 30 min using 0.1 g of activated carbon. Kinetic and isotherm modeling showed that the pseudo-second-order and Freundlich models provided the better fits, suggesting that engine-oil adsorption was influenced by active-site availability and heterogeneous surface behavior. In fixed-bed column tests, breakthrough occurred between 2 and 40 min, while saturation occurred at 62 min at a flow rate of 5 mL/min and an initial engine-oil concentration of 10 mg/L. The novelty of this work lies in evaluating date palm frond-derived activated carbon as a low-cost pretreatment adsorbent for petroleum-derived engine-oil removal from simulated seawater under both batch and fixed-bed column conditions. The proposed removal mechanism involves combined surface adsorption, hydrophobic interactions, pore filling, diffusion, and heterogeneous surface behavior. These findings indicate that the prepared adsorbent offers a promising sustainable pretreatment option for protecting desalination systems from oil-contaminated feedwater while supporting agricultural-waste valorization.