Deep Desulphurization Study of Liquid Fuels Using Acid Treated Activated Charcoal as Adsorbent

Abstract

The current study addresses the improved desulphurization activity of activated charcoal modified by acetic acid treatment. The modified activated charcoal was investigated as an adsorbent for the elimination of sulfur compounds from the model oil (consisting of dibenzothiophene (DBT) dissolved in cyclohexane) as well as real oil samples including kerosene and diesel oil. In the case of model oil, about 99.5% of DBT was removed under conditions optimized in the laboratory, which included 15 mL feed (model oil) volume, 0.8 g of adsorbent, 60 °C temperature, stirring speed of 100 rpm, and contact time of 1 h under neutral pH. In the case of real oil samples, i.e., kerosene and diesel oil, sulfur removal of 78.69% and 74.29% was attained under optimized conditions, respectively. Experimental results were interpreted through model adsorption isotherms, which indicated that the adsorption process is in close agreement with the Langmuir adsorption isotherm in comparison to the Freundlich adsorption isotherm. The spent adsorbents were regenerated to view their repeated use, simply by washing separately with organic solvents such as toluene, acetonitrile, methanol, and chloroform. Among these, toluene was found to be the best solvent for the regeneration of the spent adsorbents. The regenerated adsorbents were reused and regenerated for six consecutive regeneration cycles.

Study on adsorptive capability of acid activated charcoal for desulphurization of model and commercial fuel oil samples

“…Kerosene and diesel oil samples were characterized by using ASTM/IP standard methods. The total organic sulfur contents of the real oil samples were found to be 1.352 wt % for kerosene and 1.871 wt% for diesel oil respectively [17,19].…”

“…The porosity of the spent adsorbent was enhanced to a greater extent because of the desorption of the DBT molecules from the blind pores of the spent saturated adsorbent using toluene as a washing solvent [29]. DBT showed very high solubility in toluene and the regeneration capability was much more effective as compared to other solvents tested [17,19,30]. Fig.…”

“…The spent adsorbent regeneration studies were carried out by filtering the adsorbent saturated with DBT from the model oil at the optimized conditions. The DBT desorption was performed by washing the spent adsorbents with methanol, acetonitrile, chloroform, and toluene separately [18,19]. For each gram of the spent saturated adsorbent, about 5 mL of the tested solvent was used and were shaken for 10 min at ambient temperature (30°C).…”

“…For the characterization of kerosene and diesel samples, different physicochemical properties were examined, which meet the standard commercial kerosene and diesel oil specifications [17,19,22,23]. The total organic sulfur contents of the real oil samples were found to be high (> 1%), which must be treated to retain the sulfur content below the threshold limit [19].…”

Simultaneous Extraction of Sulfur and Nitrogen Compounds from Model Diesel Fuel Using Neoteric Green Solvents

“…Several alternative separation processes have been reported in the literature to replace the hydrotreatment process, such as adsorptive desulfurization, oxidative desulfurization, and biological desulfurization. 10 , 11 , 13 − 15 Solvent extraction technique is an attractive process as it has benign operating conditions because it can be operated at moderate temperature and pressure. 11 , 14 , 15 However, one of the major challenges in using this technique is to select the ideal solvents that would have high selectivity and capacity toward both sulfur and nitrogen compounds.…”