Effective adsorptive denitrogenation from model fuels over yttrium ion-exchanged Y zeolite

Abstract

Abstract The adsorption removal of indole and quinoline in octane with and without toluene over zeolites NaY and Yttrium Ion-exchanged Y (YY) using batch adsorption experiments was studied at 25 o C and 1 atm. YY was prepared by treating NaY with Y(NO 3 ) 3 solution twice via liquid ion-exchange method. NaY and YY were both characterized by XRD, SEM, N 2 adsorption, XRF, NH 3 -TPD, and pyridine-FTIR techniques. Adsorption isotherms of indole, quinoline and toluene in octane were conducted at 25.0 o C to explain the influence of toluene on nitrogen removal over NaY and YY. The partial destruct of the crystalline structure of NaY was observed after the introduction of yttrium ion , which led to an evident decline in BET surface area and pore volume of YY. Strong Bronsted acidity and medium Lewis acidity were introduced by yttrium ion-exchange. Though the specific surface area and pore volume of YY were much lower than those of NaY, YY exhibited equivalent adsorption capacities for indole and quinoline as NaY in model fuels without toluene. In the presence of 20 vol.% toluene, however, YY exhibited much higher adsorption capacities for indole and quinoline than NaY, especially in the case of quinoline. The improved toluene-tolerant of YY was ascribed to the strong acid-base interaction between YY and quinoline and the decreased adsorption strength between YY and toluene.