Adsorption performance and mechanisms of mercaptans removal from gasoline oil using core-shell AC-based adsorbents

Abstract

Sulfur compound detection such as mercaptans in liquid fuels is undesirable because sulfur is the main sourcing emission of sulfur oxide (SO x ) into the air. The use of activated carbon (AC) has proven to efficiently remove mercaptans. In the meantime, it is limited by the generation of the second pollution in oil, and the difficulties of recovery and regeneration. To address these issues, a core-shell structured AC with high mechanical strength and big intra-particles space were synthesized and demonstrated to efficiently remove organic pollutants from an aqueous solution without generation of the second pollution in our previous work. However, the performance, characteristics, and mechanism of mercaptans adsorption from gasoline oil by core-shell structured AC was still unclear. In this study, the mercaptans adsorption behaviors using core-shell powdered activated carbon (CSAC) and core-shell granulated activated carbon (CSGAC), along with raw PAC, PAC-core, raw GAC, and GAC-core were carried out. The results showed that both the CSAC and CSGAC adsorbents effectively removed sulfur-based pollutants and were provided with good recovery and recyclability without second pollution in gasoline oil. The CSGAC exhibited a higher mercaptans removal efficiency compared to those of CSAC as a result of the bigger intra-particles space. PAC-based adsorbents, presented the shrinking of removal efficiency after regeneration. The Pseudo-second-order kinetics and Langmuir isotherms models were dominated for mercaptans adsorption by both CSAC and CSGAC. Furthermore, the interactions between mercaptans and the composites were probably ascribed to the Van der Waals force, hydrophobic compatibility, pore texture, and π-π dispersion interaction.