Adsorptive desulphurization of model oil by Ag nanoparticles-modified activated carbon prepared from brewer's spent grains

•AgNPs/ACs have higher adsorption capacities for DBT than blank activated carbon.•Experimental data are best fitted to Freundlich isotherm.•Adsorption of DBT from model oil on the adsorbents follows pseudo second order model.•Adsorption of DBT from model oil on the adsorbents is endothermic and spontaneous.

This study reports removal of dibenzothiophene (DBT) from model oil (DBT dissolved in n-heptane) by silver nanoparticles modified activated carbon prepared from brewer's spent grains using wet impregnation (WI) method. The removal efficiency follows the order AgNPscw/AC > AgNPskp/AC> ACB. The AgNPskp/AC and AgNPscw/AC exhibit higher adsorption capacities for DBT with maximum values of 25.7 and 29.8 mg DBT/gAds at 25 °C respectively, than ACB with 13.9 mg DBT/gAds. The two-fold enhancement in the DBT uptake capacities of modified ACs can be attributed to the introduction of Ag(1) ion, a weak Lewis acid as an additional adsorption site. A significant decrease from 212.9 to 136.2 m2/g in the Brunauer-Emmett-Teller surface area of AgNPscw/AC is observed following the loading of DBT. The equilibrium adsorption data is adequately represented by Freundlich isotherm. The adsorption kinetics of DBT by these adsorbents followed pseudo second-order (PSO) model and the mechanism of adsorption was controlled by film and intra-particle diffusion. The change in entropy and heat of adsorption for DBT adsorption by these adsorbents range from 0.18 to 0.19 kJ/mol K and 21.5 to 23.9 kJ/mol, respectively. The results indicate that Ag nanoparticles-modified ACs from brewer's spent grains can be used as adsorbent for the removal of DBT from model oil.