Adsorptive removal of sulfur compounds from diesel using activated carbon and alumina modified with Cu(I) and Ni(II)

Abstract

This research studied the adsorptive capacity and selectivity of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) in simulated diesel fuels containing polyaromatic or nitrogen compounds on activated carbon and alumina, modified with CU+ and Ni2+using different preparation methods. Direct impregnation by using CuCl/CH₃CN was found to be unsuitable due to the stability and low solubility of Cu+. Impregnation was therefore performed with and aqueous solution of CuCl₂ following by a reduction step of CuCl₂ into CuCl using H₂. For Ni2+, an aqueous solution of NiCl₂ was used. A suitable feed flow rate and granulometry of the adsorbent was found to be 0.4 cm³/min and 100 to 400 μm, while the optimum temperature was 60℃ and 90℃ for Ni²+and Cu+ impregnated alumina, respectively. The adsorption capacity at the sulfur breakthrough followed the order non-impregnated macroporous alumina < Cu+/macroporous alumina < non-impregnated mesoporous alumina < Cu+/mesoporous alumina < Ni²+/macroporous alumina < Ni²+/mesoporous alumina < Cu+/AC < non-impregnated AC. The breakthrough capacity of DBT was higher than 4,6-DMDBT for both of Ni²+and Cu+/mesoporous alumina Moreover, the breakthrough capacity of DBT without polyaromatic and nitrogen compounds was higher than that with polyaromatic and nitrogen compounds.