Optimization of Ultrasound-Assisted Extraction of Spent Coffee Grounds Oil Using Response Surface Methodology

Spent coffee grounds (SCGs) generated in processing for beverages and other products are a very significant organic residue that needs to be properly treated. Waste valorization via oil extraction has the potential obtain compounds can used producing biodiesel or high-value products, such as polymers. This work focuses on ultrasound-assisted of SCG using n-hexane solvent. Three key process parameters analyzed: temperature, time, liquid/solid (L/S) rate solvent, central composite rotatable design (CCRD), an analysis that, author’s knowledge, is not yet available literature. The data were analyzed software StatSoft STATISTICA 13.1 (TIBCO Software Inc., Palo Alto, CA, USA). Results show all have statistical influence performance (p < 0.05), being L/S ratio most significant, followed by time temperature. An variance (ANOVA) showed empirical model good fit experimental at 95% confidence level. For range conditions considered this work, optimal operating obtaining yield 12 13%wt solvent around 16 mL g?1, temperature 50 60 °C, longest contact limited economics health safety issues also, boiling