Sulfur removal from model diesel fuel using granular activated carbon from dates’ stones activated by ZnCl 2

Abstract

Samples of granular activated carbon (GAC) were produced from dates’ stones by chemical activation using ZnCl 2 as an activator. Textural characteristics of GAC were determined by nitrogen adsorption at 77 K along with application of BET equation (Brunauer, Emmett and Teller) for determination of surface area. Pore size distribution and pore volumes were computed from N 2 adsorption data by applying the nonlinear density function theory (NLDFT). FT-IR spectra of GAC samples were also obtained to determine the functional groups present on the surface. GAC samples were used in desulfurization of a model diesel fuel composed of n-C 10H 34 and dibenzothiophene (DBT) as sulfur containing compound. More than 86% of DBT is adsorbed in the first 3 h which gradually increases to 92.6% in 48 h and no more sulfur is removed thereafter. The adsorption data were fitted to both Freundlich and Langmuir equations to estimate the adsorption parameters. The optimum operating conditions for GAC preparation based on high adsorption capacity are T carb = 700 °C, θ carb = 3.0 h and R = 0.5. Moreover, the efficiency of sulfur removal by GAC is reduced when applied to commercial diesel fuel. Finally, linear regression of experimental data was able to predict the critical pore diameter for DBT adsorption (0.8 nm) and validating the reported impact of average pore diameter of activated carbon on the adsorption capacity.