Immobilization of acetate based ionic liquids on silica gel to fabricate a prospective desulfurizing adsorbent

ABSTRACT Ionic liquids have the potential to play a significant role in mitigating the critical challenge of refractory sulfur removal from diesel. In the present investigation, a mixture of imidazolium, pyrazolium and triazolium acetate -based ionic liquids has been immobilized on silica gel using sol-gel technology at ambient temperature (25°C), yielding a novel adsorbent. The sol-gel processing route has been elucidated by Dynamic Light Scattering (DLS) and rheology study. The fabricated adsorbent has been characterized by Fourier Transfer Infra-red (FTIR) spectroscopy, X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The results reveal that the ionic liquids have been immobilized in the silica gel support. This adsorbent has been successfully applied to remove heterocyclic sulfur compounds from model diesel containing thiophene and dibenzothiophene. The highest desulfurization efficiencies achieved for thiophene and dibenzothiophene removal are 98.31 and 99.29% respectively, using an adsorbent with 15% ionic liquid loading, model diesel: adsorbent ratio of 1:0.075, an adsorption time of 60 minutes at 25°C. The system under investigation followed the Langmuir isotherm model and the adsorption performance best fitted with the Ho’s pseudo second-order kinetics.