Deep eutectic solvents (DES), a class of 'green' solvents, are being tested for extractive desulfurization, denitrification and dearomatization of fuels. Here, three DESs were prepared by combining betaine (B) with glycerol (Gly), ethylene glycol (EG) or propylene glycol (PG) in the molar ratios of 1:3, 1:3 and 1:3.5, respectively. The DESs were used for the removal of thiophene, pyridine and toluene from a 6-component model gasoline and for the removal of sulfur and nitrogen compounds from a real fluid catalytic cracking (FCC) gasoline. Physical properties of the prepared DESs -density, viscosity, refractive index, specific conductance, thermal conductivity, temperature diffusivity and heat capacity were determined, too. All tested DESs exhibit higher potential for denitrification of model fuel with respect to desulfurization and dearomatization. B-PG 1:3.5 worked best in one-stage denitrification of both model gasoline (∼ 80%) and real FCC gasoline (∼ 36%). The reuse of solvent without loss in extraction efficiency in four extraction stages was successfully achieved for all three DESs by evaporation purification of DES between the stages.
Samples of cretaceous limestone have been treated with three application methods (poultice, immersion and brushing) using different concentrations of ammonium oxalate solution (AmOx) and varying treatment time in order to test the efficiency of surface and in-depth formation of a protective layer of calcium oxalate (CaOx). Synchrotron-based microanalytical techniques (SR-µXRD with 12.5 µm × 7.5 µm (H × V ) probe size, SR-µFTIR with 10 µm × 10 µm and 8 µm × 20 µm probe sizes) and laboratory µFTIR, XRD and SEM have been employed for analysis of the treated samples. Synchrotron-based techniques showed variations in the CaOx distribution along the surface on a micrometer scale. All treatments resulted in the
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