Abstract
This study investigated the catalytic conversion of WCO using bentonite as a low-cost silica-alumina catalyst to produce a hydrocarbon-rich liquid containing green-diesel-range components. WCO was pretreated at 105 °C, while bentonite was dried at the same temperature and characterized by SEM-EDX, BET surface-area analysis, and TGA. Catalytic cracking was conducted at 350 °C using bentonite loadings of 1, 3, and 5 wt%. The liquid products were evaluated by GC-MS, FT-IR, cetane-related fuel-property analysis, and physicochemical tests. Increasing catalyst loading improved WCO conversion and liquid-product yield. At 5 wt% bentonite, the conversion and liquid-product yield reached 99.236 and 75.768 wt%, respectively, while coke formation decreased to 0.763 wt%. GC-MS showed that this product was dominated by the kerosene-range fraction (65.79%) and contained 18.25% diesel-oil-range compounds. FT-IR indicated substantial deoxygenation through decreased carbonyl intensity and disappearance of the carboxylic-acid O-H region. The product showed a cetane-related value of 48.2, viscosity of 4.93 mm²/s, density of 862 kg/m³, flash point of 39 °C, corrosion class 1a, and carbon residue of 0.100069% m/m. Among the investigated catalyst loadings, 5 wt% bentonite gave the best overall catalytic performance; however, the low flash point and broad product distribution indicate that further upgrading and optimization are required before the product can be considered a drop-in diesel fuel.