engleski

Application of nanosuspension in extractive denitrification and desulfurization of fuels

In order to protect environment and meet the very strict requirements which are imposed in recent years, denitrification and desulfurization are the subject of great interest. The conventional method of removing sulfur and nitrogen compounds (hydrodesulfurization) requires high temperatures and pressures as well as large amounts of hydrogen and it is necessary to find new and environmentally friendly methods of fuel purification. Well designed liquid-liquid extraction can be one of such processes. Extraction is considered environmentally friendly process since it operates under mild conditions (low temperatures and pressures) and a possible choice of favorable solvents. Comparable yields of removing undesirable components in extraction process is tried to be achieved by application of so called “green solvents” (ionic liquids and recently deep eutectic solvents, DES). Despite of the green character of DES, low efficiency of desulphurization and denitrification can be the problem for widespread use. Although, the application of DES has been subject of the many researches in the last few years, this paper made a step forward by applications of DES in nanotechnology. Namely, a significant improvement in the mass transfer is achieved by using nanosuspension in the extraction process. For synthesis of DES choline chloride (CHCl) was selected as a typical hydrogen bond acceptor and glycerol (Gly), glucose (Glu) and malic acid (MA) as a hydrogen bond donor. Nanosuspensions were prepared by dispersing nanoparticles of Al2O3 (0.3% vol.) in these DESs. Applied nanosuspension was stable over 15 days. Physical properties (density, viscosity, and pH) of DESs and prepared nanosuspensions were determined. Extraction of phiridine and tiophen have been performed with DES and corresponding nanosuspensions (CHCl:Gly, CHCl:MA with 30 wt % H2O and CHCl:Glu30 with 30 wt % H2O). For all performed experiments and all used solvents, extraction efficiency of pyridine was higher than the efficiency of thiophene. Extraction of the key components from isooctane as the primary solvent gave the best results. It was confirmed that the applied nanoparticles mostly enhance mass transfer for all tested systems, in some cases up to 40 %. This improvement can be explained with Brownian motion of well-dispersed nanoparticles which enhance mass transfer.

deep eutectic solvent ; denitrification ; desulfurization ; extraction ; nanosuspension

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