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During the past decade, various experimental studies have shown that ionic liquids exhibit interesting and attractive thermo-physical properties such as extremely low volatilities, a high thermal stability, and ionic conductivity as well as high gas solubilities. It is in the latter where the use of an ionic liquid as gas separation media seems to be very promising particularly for the capture/sequestration of carbon dioxide (CO 2 ) which has been shown to be highly soluble in ionic liquids as compared with other gases. Recently, a significant amount of experimental work has appeared in the literature dealing with the solubility of CO 2 in several ionic liquids at different temperature and pressure conditions. A detailed analysis of these works reveals that the highest solubilities of CO 2 have been exhibited in ionic liquids having cations of the imidazolium type together with anions of the [TF 2 N] type. The purpose of this work is to present a formal modeling approach of the CO 2 solubility in the aforementioned ionic liquids by the use of a cubic equation of state (Soave or Peng−Robinson) coupled with modern mixing rules of the Wong−Sandler type. The resulting modeling approach proves to be able to correlate and/or predict the CO 2 solubility in ionic liquids over diverse conditions of temperature, pressure, and solute composition.

The extraction of feather keratin biopolymer structures was studied using chicken feathers as a biomass material by the cold acid hydrolysis reaction; the recrystallization stage was performed using microwave or ultrasound irradiation, and conduction heating was used as a reference. The microwave or ultrasound irradiation modified the texture and the morphology of the obtained materials, and they can be controlled depending on the time exposure and the power of the irradiation; this has high relevance in the design of new materials to obtain nanostructures depending on the specific application. It was found that the microwave irradiation promotes the growth of the beta sheet over the alpha helix, and in the case of ultrasound irradiation, the growth is reversed being similar to the conduction heating; the porosity properties remain invariant, modifying the particle sizes depending on the exposure time and power of irradiation. Therefore, the feather keratin biopolymer, when modified by microwaves and ultrasound in the recrystallization stage, is a fibrous protein that has good mechanical, structural, morphological, and thermal properties with potential applications such as development of biocompatible materials with cellular interaction and in catalysis as catalytic and enzymatic support to mention just a few.

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In this study, CuO was synthesized as a microwave absorber in the pyrolysis of a biomass model (sugarcane bagasse). CuO was synthesized for 5 min of irradiation using the following techniques: microwave (MW), ultrasound (US), combined mode (MW-US), and conduction heating (CH) as a reference material. The use of these treatments promotes changes in the morphology, as MW and US generate leaves and monolithic faceted morphologies, respectively. Changes were also generated in some textural characteristics such as crystal size, surface area, and volume-pore size. They were produced as a consequence of changes in the conditions during the crystallization stage produced by the different irradiation types. The microwave-assisted pyrolysis was performed aiming for the maximum liquid fraction (bio-oil) in the products. The reaction time, the size of the biomass, and the CuO synthesis method were also analyzed. The following particle size (ps) intervals were studied: ps < 0.5 mm, 0.5 mm < ps < 1.7 mm, 1.7 mm < ps < 3.5 mm. The best conditions at 1160 Watts in the microwave were: 4 min of reaction, particle size lower than 0.5 mm, and CuO synthesized by US. The use of CuO in the pyrolysis almost triples the amount of the obtained liquid fraction, when compared with the pyrolysis without the use of a microwave absorbent. The CuO was reduced to Cu2O and Cu after the pyrolysis. In this work, a reduction in the reaction times from hours to minutes was achieved during the synthesis of CuO and the pyrolysis biomass. The liquid fraction (bio-oil) can be raw material to obtain value-added chemical products or biofuels.