OICC Press International Journal of Industrial Chemistry 2228-5547 16 1 2025 03 31 Evaluation and Optimization of Ultra-Assisted Extractive Desulfurization of the Fuel Model 10.57647/j.ijic.2025.1601.06 EN Azadeh Khoshdel Department of chemical Engineering, Quchan Branch, Islamic Azad University, Quchan, Iran Ehsan Firouzfar Department of chemical Engineering, Quchan Branch, Islamic Azad University, Quchan, Iran Behrooz Mahmoodzadeh vaziri Department of chemical Engineering, Quchan Branch, Islamic Azad University, Quchan, Iran Sharareh Mohseni Department of Chemistry, Quchan Branch, Islamic Azad University, Quchan, Iran Javad Feizy Department of food safety and quality control, research Institute of food science and technology, Mashhad, Iran Journal Article 2025 03 31 In this study, the dibenzothiophene (DBT) extracted from n-octane fuel model by ultrasound assisted extractive process. Sulfolane and  Deep Eutectic Solvent (DES) sulfolane were used in the DBT extraction process. The effects of sonication time, ultrasonic temperature and frequency on the extraction percentage of DBT were studied. The optimum extraction technology of DBT from fuel was determined by response surface optimization test. The optimal conditions that were obtained for the DBT extraction percentage by sulfolane at higher value, are including, Ultrasonic time: 23.3 oC, Temperature: 25 oC and Frequency: 15.55 Hrz.  Also, these optimal values for DBT extraction with DES were obtained 39.9 min, 50 oC and 19.09 Hrz for time, temperature and ultrasonic frequency, respectively. Ultrasound-assisted extraction has demonstrated a superior DBT yield compared to conventional extraction techniques.