Abstract
This study presents the development of Fe-Co-Ni mixed-metals oxide composites that were synthesized via chemical precipitation method at different reaction times (05-8 h). These composites were subsequently utilized to achieve deep sulfur removal from diesel fuel through ultrasoumd-assisted oxidative desulfurization (UAOD). Among those composites, the obtained composite at a synthesis time of 0.5 h emerged as the most efficient catalyst, achieving nearly 60% sulfur removal under optimized operating conditions (60 °C, 90 min as reaction time, catalyst dose of 10 g/L and a 1:1 H(2)O(2)-to-feed ratio). A subsequent sulfur removal of 89% was achieved through post-treatment with a DMF-acetonitrile solvent mixture (4:1 solvent-to-feed ratio), validating the synergy between catalytic oxidation and solvent extraction. The exceptional performance by this Fe-Co-Ni composite was further amplified by a structure modification through production of core-shell composite using a layer of polystyrene. This composite achieved reduction of sulfur content to 920 ppm (from 21,700 ppm in feedstock) which represented a sulfur removal percentage of approximately 96%. Therefore, the introduced approach can be considered for scalable and energy-efficient processes for producing low-sulfur diesel, aligning with global environmental demands.