Enhanced adsorption desulfurization performance over modified zeolite clinoptilolite for a model fuel in a competitive process

• Published in: Research on chemical intermediates 2023-07, Vol.49 (7), p.3097-3133
• Main Authors: Maghsoudi, Zahra, Shabanian, Seyed Reza, Ahmadpour, Javad, Ghorbani, Mohsen
• Format: Article
• Language: English
• Subjects: Adsorption; Ammonia; Catalysis; Cerium; Chemistry; Chemistry and Materials Science; Clinoptilolite zeolites; Copper; Dibenzothiophene; Inorganic Chemistry; Physical Chemistry; Sulfur; Sulfur compounds; Surface area; Surface chemistry; Toluene; Zeolites
• ISSN: 0922-6168; 1568-5675
• DOI: 10.1007/s11164-023-05039-x

In this study, modified samples of natural clinoptilolite zeolite were prepared to investigate the adsorption capacity of sulfur compounds in different model fuels. For this goal, mesoporous clinoptilolite zeolite was prepared by sequential dealumination and desilication process and then impregnated with two metals, copper (Cu) and cerium (Ce). The samples were characterized by XRD, BET, FE-SEM, FT-IR, EDS and NH 3 -TPD. The results showed that dealumination and desilication processes led to a significant increase in the total and mesoporous surface area of the modified zeolite. The surface area and the total pore volume of the parent sample were measured as 18.7 m 2 /g and 0.057 cm 3 /g, respectively, which increased to 73.7 m 2 /g and 0.107 cm 3 /g for the modified sample meso1_CZ. In Cu-CZ, Ce-CZ and CuCe-CZ impregnated samples because of presence of d-electrons, sulfur compounds interact with the cations through π-complexation that resulted better performance comparing the parent zeolite, in which CuCe-CZ, with adsorption capacity of 31.03 and 31.05 mg/g for thiophene and dibenzothiophene, respectively, has the highest capacity to adsorb sulfur compounds. The results also showed that by adding toluene and cyclohexene to the gasoline model fuel for a competitive adsorption process, the adsorption capacity reduced somewhat, so that the reduction percentage value is lower for the zeolite containing Ce compared to the zeolite containing Cu. The kinetic models in adsorbing the sulfur compounds followed the pseudo-second-order equation. For adsorption of dibenzothiophene onto CuCe-CZ sample, Langmuir was the best-fitting isotherm to the experimental data.