Experimental Investigation of Adsorption of Sulfur Compounds from Model Fuel with Modified NaY Zeolite Adsorbent

Adsorption capacity and selectivity are two major challenges that adsorption desulfurization faces. One way to overcome these challenges is to use mesoporous zeolites. In this study, the effects of mesoporosity on the adsorption desulfurization performance with NaY zeolite adsorbent were investigated. In order to optimize the parameters, the desilication operation was performed with a mixture of sodium hydroxide (NaOH) and tetrapropylammonium hydroxide (TPAOH) solution at room temperature with ratios of R=  = 0, 0.25, 0.5, 0.75. The adsorbents were characterized by XRD, BET, FE-SEM and FT-IR. The results showed that ATY (0.5)-0.25R adsorbent has the highest mesopore surface with the value of 54.03 m2/g. Meanwhile, the adsorption desulfurization performance in a batch reactor was tested using different model fuels containing the sulfur compounds thiophene and dibenzothiophene. The results showed that different ratios of NaOH/TPAOH solution play an important role in the adsorption of sulfur compounds. In addition, Cu metal ion was impregnated on the parent zeolite and ATY (0.5M)-0.25R adsorbents in order to increase the adsorption capacity. It has been shown that the adsorption capacity of the adsorbents increases with ion exchanging of Cu metal ion, so that the Cu-0.25R adsorbent has the highest adsorption capacity of the sulfur compounds thiophene and dibenzothiophene with the values ​​of 18.28 and 21.83 mg S/g, respectively. In this regard, the effect of temperature on the Cu-0.25R adsorbent on the adsorption of thiophene has been investigated. It has been shown that, the adsorption of thiophene has increased with increasing temperature and has reached its maximum at 50 ° C. Thermodynamic studies showed that the adsorption process is endothermic. The kinetic models of adsorption of sulfur compounds followed the pseudo – second – order equation. The adsorption isotherm was well matched to the Langmuir isotherm equation and its maximum adsorption capacity for thiophene and dibenzothiophene sulfur compounds was 18.38 and 23.43 mg/g, respectively.