Ultrasound‐assisted wool scouring using sophorolipid biosurfactant and its environmental assessment

Abstract This study reports the application of a sophorolipid biosurfactant for scouring raw wool and its synergy with ultrasound technology. These ultrasonic scouring process parameters were optimised using the Box–Behnken Design of statistical Response Surface Methodology. The final parameters for ultrasonic scouring of Indian‐origin raw wool after statistical optimisation were found to be 2% sophorolipid biosurfactant concentration at 50°C for 45 min. The treated wool fibres showed an average sinking time within 5 s. A vis‐à‐vis analysis with the conventional raw wool scouring process showed that ultrasound‐assisted scouring achieved a residual grease content of 0.98% compared to 1.5% in conventional scouring. The synergistic effect of ultrasound and sophorolipid formulation enabled efficient removal of grease, suint and dirt at 10°C lower temperature and 15 min of less time than the conventional wool scouring process. Effluent characterisation revealed a COD reduction from 2446 to 1980 mg/L, TDS decrease from 3050 to 2500 mg/L and a near‐neutral pH of 7.94 in the sophorolipid system compared to 10.7 in conventional scouring. Although the BOD increased from 734 to 1386 mg/L owing to the higher biodegradability of sophorolipids, the COD/BOD ratio is reduced. The Bradford assay indicated lower protein leaching (0.12 mg/mL) in the ultrasound‐assisted sophorolipid bath compared to 0.3 mg/mL in conventional scouring effluent. These results demonstrate that ultrasound‐assisted sophorolipid scouring not only enhances fibre quality but also reduces effluent load and environmental impact. The developed process represents a sustainable and energy‐efficient alternative to conventional wool scouring systems.