Alicia García-Abuín

Physicochemical characterization of chitosan derivatives

The present work analyses different chitosan synthesized derivatives from the point of view of their chemical structure (Fourier transform infrared spectroscopy, deacetylation degree, elemental analysis and average molecular weight) as well as different physicochemical properties such as density, kinematic and dynamic viscosity, intrinsic viscosity and surface tension. The characterization of different solutions of these solutes has a high importance due to the large potential uses of these compounds. Chitosan has low solubility in water, and for this reason, the present work has synthesized soluble chitosan derivatives. Important differences between original chitosan and synthesized derivatives have been found in different properties.The present work analyses different chitosan synthesized derivatives from the point of view of their chemical structure (Fourier transform infrared spectroscopy, deacetylation degree, elemental analysis and average molecular weight) as well as different physicochemical properties such as density, kinematic and dynamic viscosity, intrinsic viscosity and surface tension. The characterization of different solutions of these solutes has a high importance due to the large potential uses of these compounds. Chitosan has low solubility in water, and for this reason, the present work has synthesized soluble chitosan derivatives. Important differences between original chitosan and synthesized derivatives have been found in different properties.

Hydrodynamic and absorption studies of carbon dioxide absorption in aqueous amide solutions using a bubble column contactor

The present work analyses the carbon dioxide absorption process in aqueous n-alkylpyrrolidones solutions, from the point of view of hydrodynamic studies as well as mass transfer, using a bubble column contactor. An analysis of the influence of solute concentration and gas flow-rate is complemented by the study of the effect caused by the alkyl group on the hydrodynamics and mass transfer. The presence of this kind of substance produces a decrease in mass transfer rate, but on the basis of interfacial area and mass transfer coefficient values, ethyl-2-pyrrolidine (EP) shows suitable characteristics to replace methyl-2-pyrrolidine (MP) in gas separation processes due to its lower safety problems.

Chemical Reaction Effect upon Gas–Liquid Interfacial Area in a Bubble Column Reactor

Abstract This work analyses the influence of different experimental conditions over important hydrodynamic parameters of a bubble column reactor, such as bubble size distribution, gas hold-up and the gas–liquid interfacial area. The influence of gas flow-rate (18–40 L h–1) and reagent concentration (0–0.5 mol L–1) in the liquid phase upon these hydrodynamic parameters have been studied. The influence of experiment time must also be taken into account due to non-steady-state regime. Under these considerations, the chemical absorption rate changes throughout time, and it produces important changes upon the global absorption process, due to modifications in the gas–liquid interfacial area. The presence of a fast reaction in the liquid bulk has the highest influence upon interfacial area.

Influence of a Second Liquid Phase upon Carbon Dioxide Chemical Absorption

Abstract This work analyzes carbon dioxide mass transfer rate during chemical absorption from a gas phase to a liquid–liquid system based on an aqueous phase (glucosamine or pyrrolidine solutions) and an organic one. Two different kinds of silicone oil with different viscosity were used to perform the liquid phases, and it allows the analysis of the influence of this variable upon mass transfer rate. In these systems, a surfactant (Tween80) was added to stabilize the liquid–liquid system, and therefore, the influence of the presence of this surfactant in the liquid phase was studied. This substance produces a positive effect upon carbon dioxide absorption rate in glucosamine aqueous solutions, but the opposite effect was observed for the other amine employed in this work. Also, the influence caused by different operation variables, such as the gas flow-rate fed to the bubble contactor or the silicone oil concentration in the liquid phase, was studied.