Metal-loaded polystyrene-based activated carbons as dibenzothiophene removal media via reactive adsorption

To improve the desulfurization capability of activated carbons, new metal-loaded carbon-based sorbents containing sodium, cobalt, copper, and silver highly dispersed within the carbon matrix were prepared and tested at room temperature for dibenzothiophene (DBT) adsorption. The content of metals can be controlled by selective washing. The new adsorbents showed good adsorption capacities and selectivity towards DBT. The metals incorporated to the surface act not only as active sites for selective adsorption of sulfur-containing aromatic compounds, but also as structural stabilizers of the carbon materials, and as catalyst initiators in reactive adsorption. Depending on the reactivity of the metal used, the adsorption capacity of the activated carbons significantly varied. Cobalt and copper loaded carbons showed the highest uptakes, due to not-well defined catalytic synergetic effects. Besides, the presence of sulfur compounds in the structure of the carbon as a result of the sulfonic moiety of the precursor, results in sulfur–sulfur specific interactions leading to an enhancement in the adsorption capacity for DBT removal.