A simultaneous study on desulphurization and denitrogenation using acid-treated activated alumina: Multi-component adsorption systems

In this study, sulphuric acid-treated activated alumina (AA) was used for sulphur and nitrogen removal from model fuel in a batch adsorption study. Dibenzothiophene (DBT), a sulphur compound, and quinoline, a nitrogen compound dissolved in isooctane, were taken as a model liquid fuel. Detailed characterization of the adsorbent, such as scanning electron microscopy (SEM), thermogravimetric analysis-differential thermal analysis (TGA-DTA), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), and X-ray diffraction (XRD), was performed to understand the DBT and quinoline adsorption mechanism onto AA adsorbent. Sulphur and nitrogen removal efficiencies were found to be 64% and 91%, respectively. Mono-component adsorption isotherm was studied by using different models such as Langmuir, Freundlich, and Redlich-Peterson (R-P) isotherms. The R-P isotherm model well-predicted the individual equilibrium data for both nitrogen and sulphur from the liquid fuel. Binary-component adsorption studies were performed by mixing both DBT and quinoline in isooctane. Binary-equilibrium data were modelled by multi-component models such as modified Langmuir isotherm, non-modified Langmuir, extended Langmuir, extended Freundlich isotherm, Sheindorf-Rebuhn-Sheintuch (SRS), non-modified R-P model, and modified R-P model. The extended Freundlich (E-F) adsorption isotherm model was found to best fit the binary equilibrium system.