Optimization of crude palm oil bleaching process using nano SiO2-bleaching earth: A sustainable approach for enhanced quality and efficiency

The palm oil industry faces growing challenges in balancing product quality, resource efficiency, and environmental sustainability. Conventional bleaching earth (BE), widely used to purify crude palm oil (CPO), often requires high dosages, shows limited adsorption efficiency, and generates large amounts of spent bleaching earth (SBE) waste that is difficult to manage. To overcome these limitations, this study explores the enhancement of BE with nanosilica (nano SiO 2 ) to create an improved bleaching agent. Response Surface Methodology (RSM) was applied to evaluate the influence of BE concentration, temperature, and contact time on β-carotene removal and color improvement. Compared to commercial BE, the nano SiO 2 -BE composite exhibited significantly higher bleaching performance and product clarity. The optimal conditions were identified at 1 % BE concentration, 70 °C, and 90 min of contact time, under which the β-carotene content was reduced to 408.18 mg/L, and the color quality exceeded industrial benchmarks. The quadratic regression models demonstrated strong predictive power, with R² values above 0.965 for both response variables. BET analysis revealed a nearly twofold increase in surface area, and EDS confirmed effective silica incorporation. These structural improvements contributed to greater active site accessibility and adsorption efficiency. Overall, this study highlights nano SiO 2 -BE as a cost-effective and eco-friendly alternative for industrial CPO bleaching, offering enhanced resource utilization, reduced waste generation, and alignment with sustainability goals. • Nano SiO 2 -modified bentonite effectively enhanced β-carotene removal and oil color clarity. • Optimized conditions (1 % BE, 70°C, 90 min) reduced β-carotene to 408.18 mg/L, meeting industrial standards. • Response Surface Methodology (RSM) provided reliable models (R 2 > 0.965) for process optimization. • The process minimized material usage and spent bleaching earth (SBE) generation, supporting sustainability. • Nano SiO 2 -BE offers a cost-effective, eco-friendly alternative for large-scale CPO bleaching.