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The corrosion behaviour of mild steel (MS) was systematically investigated as a function of the alkyl chain length in the cation of 1-alkyl-3-methylimidazolium tricyanomethanide ([C n mim]TCM, n ¼ 2, 4, 6 and 8) ionic liquids (ILs) with respect to their potential application as a structural material and solvents for CO 2 capture plants respectively. The surface of MS was examined by scanning electron microscopy, energy dispersive X-ray spectroscopy and micro-Raman mapping before and after immersion testing at temperatures of 70 and 80 C for durations varying from 1 hour to 10 days. Corrosion initiates at the sites of MnS inclusions on the surface of MS, resulting in the formation of cavities due to the MnS dissolution, which may be surrounded by corrosion products containing magnetite (Fe 3 O 4 ) and maghemite (g-Fe 2 O 3 ). The amount of the corrosion products generated around the inclusion sites decreased with the increase of the cation alkyl chain length, following the order [C 2 mim]TCM > [C 4 mim] TCM > [C 6 mim]TCM z [C 8 mim]TCM. This was attributed to the corrosion inhibition effect of the ILs through adsorption on the metal surface and blocking active sites, with the inhibition efficiencyincreasing with the alkyl chain length. The underlying mechanism was associated with corrosion processes at active sites on the MS surface, such as sulphide inclusions, in the presence of residual water and oxygen in the IL. It was shown that increase of the water content in the ILs to about 50 000 ppm resulted in faster dissolution of the MnS inclusions. Finally, it was demonstrated that removal of oxygen from the IL significantly reduced the corrosion rate.

Similar to spontaneous emission of photons and inelastic (Raman) scattering, elastic (Rayleigh) scattering of light is controlled by spectraland spatial distribution of photon density of states, DOS (density of electromagnetic modes). However, to date Rayleigh scattering in nanoporous media has not become the subject of discussion in the context of photon DOS effects. In this paper, we consider light scattering in porous materials in the context of spectral, spatial, and angular redistribution of photon DOS in materials with pores whose size and spacing are of the order of light wavelength. The DOS effect results in predictable and controllable modification of scattering and can be purposefully used in certain light harvesting and illumination systems. A possible role of the effect in the cornea of eye is outlined for seeing at grazing incidence of light beams with respect to an eye pupil.Photon density of states, DOS (density of electromagnetic modes) appears in a number of formulas describing emission of photons by matter. First of all, it appears in the Plank's formula for spectral density of equilibrium (thermal) electromagnetic radiation. The density of equilibrium electromagnetic radiation is the product of photon energy, BoseEinstein distribution function, and photon DOS value. Second, photon DOS is known to appear in the expression for the lifetime of excited atoms, molecules, and solids since spontaneous emission of photons is viewed as stimulated emission with stimulating photons coming from zero-point oscillations of electromagnetic field. 1 Third, photon DOS can be found as a factor in formulas describing inelastic (Raman) scattering of photons by molecules and solids. 2 Finally, photon DOS factor is in the expression for the probability of elastic (Rayleigh) scattering of photons. 3 Similar to inelastic scattering, elastic scattering in terms of quantum electrodynamics is considered as virtual excitation of matter with subsequent photon emission. Elementary photon emission is considered as a result of interaction of an excited (actually or virtually) quantum system with electromagnetic zero-field fluctuations. Accordingly, the spontaneous emission rate, the probability of inelastic and elastic scattering of photons, is proportional to photon DOS. In a homogeneous space, the scattering rate W for photons with frequency ω into elementary solid angle dΩ reads where I(ω) is the incident photon flux, V is the matrix element for photon emission, and D(ω) is photon DOS. In a continuous medium, photon DOS D(ω) is expressed by the formula where c is the speed of light in vacuum and n is the refractive index of a medium under consideration (see, e.g., refs 1 and 2 and refs therein for more detail on DOS in various media). Noteworthy, the well-known ω 4 dependence of scattering probability, which is responsible for the blue sky color and sunset/sunrise redness, occurs essentially from the contribution of D(ω) in the form of eq 2. In complex media such as dense sols, matrices with pores, cavities, or inclusions ...

The CO 2 capture efficiency of nine newly synthesized ionic liquids (ILs), both in their pure states as well as in binary and ternary systems with water and amines, was investigated. The study encompassed ILs with fluorinated and tricyanomethanide anions as well as ILs that interact chemically with CO 2 such as those with amino acid and acetate anions. Compared to amines, some of the novel ILs exhibited a majority of important advantages for CO 2 capture such as enhanced chemical and thermal stabilities and negligible vapor pressure; the previous features counterbalance the disadvantages of lower CO 2 absorption capacity and rate, making these ILs promising CO 2 absorbents that could partially or totally replace amines in industrial scale processes. In addition to their ability to capture CO 2 , important issues including corrosivity and ecotoxicity were also examined. A thorough investigation of the capture efficiency and corrosion properties of several solvent formulations proved that some of the new ILs encourage future commercial-scale applications for appropriate conditions. ILs with a tricyanomethanide anion confirmed a beneficial effect of water addition on the CO 2 absorption rate (ca. 10-fold) and capacity (ca. 4-fold) and high efficiency for corrosion inhibition, in contrast with the negative effect of water on the CO 2 absorption capacity of ILs with the acetate anion. ILs with a fluorinated anion showed high corrosivity and an almost neutral effect of water on their efficiency as CO 2 absorbents. ILs having amino acid anions presented a reduced toxicity and high potential to completely replace amines in solutions with water but, in parallel, showed thermal instability and degradation during CO 2 capture. Tricyanomethanide anion-based ILs had a beneficial effect on the capture efficiency, toxicity, and corrosiveness of the standard amine solutions. As a consolidated output, we propose solvent formulations containing the tricyanomethanide anion-based ILs and less than 10 vol % of primary or secondary amines. These solvents exhibited the same CO 2 capture performance as the 20−25 vol % standard amine solutions. The synergetic mechanisms in the capture efficiency, induced by the presence of the examined ILs, were elucidated, and the results obtained can be used as guidance for the design and development of new ILs for more efficient CO 2 capture.