photocatalytic reduction of carbon dioxide to formaldehyde was investigated on four semiconductor photocatalysts (fes, fes/fes2, nio and tio2). the reaction was carried out in continues flow of co2 gas bubbled into the reactor. semiconductor photocatalysts were characterized by x-ray diffraction (xrd) and diffuse reflectance spectroscopic (drs) methods. sulfide ion was used as hole scavenger. t...

Carbon dioxide capture from ambient air could compensate for all carbon dioxide emissions to the atmosphere. Such capture would, for example, make it possible to use liquid, carbon-based fuels in cars or airplanes without negatively impacting the climate. We present a specific approach based on a solid sorbent in the form of an anionic exchange resin, that absorbs carbon dioxide when dry and re...

In this work, an equation of state (EoS) is developed to predict accurately the phase behavior of ionic liquid + CO2 systems based on the truncated perturbed chain polar statistical associating fluid theory (tPC-PSAFT) EoS. This EoS accounts explicitly for the dipolar interactions between ionic liquid molecules, the quadrupolar interactions between CO2 molecules, and the Lewis acid-base type of...

Tubular solar thermal receivers suitable for central towers are modelled using energy and exergy analysis, in a way that allows individual inspection of the the irreversibilities associated with the various receiver heat transfer processes occurring. The model was used to compare the behaviour of four working fluids: molten salt (NaNO3/KNO3), liquid sodium metal, supercritical carbon dioxide, a...

Although the results we have recorded merely serve to indicate the possibilities of this interesting field of investigation, we have sufficient data to enable us to draw certain general conclusions. In the first place it is evident that the bloods of the more highly developed marine invertebrates, such as the active Crustacia and the Cephalopods, are specially adapted for the carriage of carbon...

Ecological aspects of coal combustion utilization of CO2 from flue gas Slovakia belongs to the group of twenty worst polluters throughout the world, releasing 10 12 tons of carbon dioxide per capita, whereas the worldwide average value is about 5 tons. It is known that the big electric and thermal power stations produce only 25 % of the overall production of carbon dioxide in Slovakia, whereas ...

A solid hydrazine was isolated as a crystalline powder by reacting aqueous hydrazine with supercritical CO(2). Its structure determined by single crystal X-ray diffraction shows a zwitterionic form of NH(3)(+)NHCO(2)(-). The solid hydrazine is remarkably stable but is as reactive as liquid hydrazine even in the absence of solvents.

We examine the utility of the virial equation of state (VEOS) for the prediction of the solubility of hexane in supercritical carbon dioxide. We computed virial coefficients up to fourth-order for this mixture at 353.15 K, using Mayer-sampling Monte Carlo applied to established molecular models for carbon dioxide and hexane. At this temperature, neither the thirdnor fourth-order VEOS indicate t...

The present paper is a numerical and experimental comparative study of hermetic and semi-hermetic reciprocating compressors working with carbon dioxide as fluid refrigerant against the conventional R134a hermetic compressors. When cooling conditions for one-stage compressor type (i.e., evaporation temperatures between 7.2oC and –10oC) have been considered, the numerical and experimental results...