Ultra-deep desulfurization of mercaptan by cyclic selective adsorption-reactive regeneration at room temperature

A cyclic process of selective adsorption-reactive regeneration over bifunctional Z-sorb was proposed for desulfurization of heavy mercaptan from gasoline under ambient conditions. A pronounced adsorption capacity (25.7 mg-S/g-adsorbent) and selectivity (206.1, ~10 times over 1-hexene) of heptanethiol over bifunctional Z-sorb were achieved, which can be attributed to the strong adsorbate–adsorbent interaction calculated as high as −44.6 kJ/mol. Catalytic reactive regeneration was proposed to remove stubbornly adsorbed heptanethiol, which achieved complete recovery of Z-sorb in multiple cycles under room temperature. With the aid of minor H₂O₂, the strongly adsorbed heptanethiol in the form of metal-thiolate (Zn-SR) transformed to readily desorbed disulfide, which was elucidated via the combined experiment and density functional theory calculations. The developed process provides insights to resolve the trade-off between adsorption selectivity and regenerability, paving the way for energy-efficient industrial adsorptive de-mercaptan of gasoline.