Adsorptive desulphurisation of benzothiophene and dibenzothiophene from model fuels with modified vermiculite

Vermiculite clay was modified with calcium oxide in order to remove Dibenzothiophene (DBT) and Benzothiophene (BT) from Model Fuels (1:1 volume mixture of decane and hexadecane). Composite was prepared with a wetness impregnation method. The physicochemical properties of these adsorbents were characterised using thermal gravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), field-scattering scanning electron microscopy (FE-SEM), transient electron microscopy (TEM), and X-ray diffraction (XRD) analysis. The vermiculite-calcium oxide (VE-Ca) composite showed the highest adsorption capacity at an initial concentration of 30 mg/L, adsorbent dose of 120 mg, and contact time of 120 min at 25 degrees C. The highest adsorption capacity for DBT and BT was 85.37 mg.g(-1) and 93.7 mg.g(-1) on VE-Ca composite, respectively. The adsorption equilibrium data were fitted to pseudo-second order kinetic and Freundlich isotherm models. The results showed the presence of calcium due to pi_complexation between Ca2+ and thiophenic aromatic rings and chemical bonding between metals and sulphur which would improve the adsorption capacity for desulphurisation.

Automated summary

In this study, vermiculite clay modified with calcium oxide was used as a composite adsorbent for the removal of DBT and BT from model fuels. The adsorption capacity and physicochemical properties of the composite were investigated.