A thermogravimetric technique based on a magnetic suspension balance operating in dynamic mode was used to study the thermodynamics (in terms of solubility and Henry's law constants) and kinetics (i.e., diffusion coefficients) of CO2 in the ionic liquids [bmim][PF6], [bmim][NTf2], and [bmim][FAP] at temperatures of 298.15, 308.15, and 323.15 K and pressures up to 20 bar. The experimental technique employed was shown to be a fast, accurate, and low-solvent-consuming method to evaluate the suitability of the ionic liquids (ILs) to be used as CO2 absorbents. Thermodynamic results confirmed that the solubility of CO2 in the ILs followed the order [bmim][FAP] > [bmim][NTf2] > [bmim][PF6], increasing with decreasing temperatures and increasing pressures. Kinetic data showed that the diffusion coefficients of CO2 in the ILs followed a different order, [bmim][NTf2] > [bmim][FAP] > [bmim][PF6], increasing with increasing temperatures and pressures. These results evidenced the different influence of the IL structure and operating conditions on the solubility and absorption rate of CO2, illustrating the importance of considering both thermodynamic and kinetic aspects to select adequate ILs for CO2 absorption. On the other hand, the empirical Wilke-Chang correlation was successfully applied to estimate the diffusion coefficients of the systems, with results indicating the suitability of this approach to foresee the kinetic performance of ILs to absorb CO2. The research methodology proposed herein might be helpful in the selection of efficient absorption solvents based on ILs for postcombustion CO2 capture.

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We have studied the suitability of a cryogenic process (e.g., ice-segregation-induced self-assembly, ISISA) for preparation of polyvinyl alcohol (PVA) scaffolds with in situ immobilized bacteria (e.g., Escherichia coli). Confocal fluorescence microscopy and impedance measurements were used to evaluate the extension of bacteria proliferation within the scaffold macrostructure. The bacteria efficiency for colonization of the scaffold macrostructure is compared for bacteria immobilized with and without the use of additional cryoprotectans. Cryoprotection by bacteria entrapment in alginate beads containing glucose results in a significant improvement (more than 2-fold as compared to non-cryoprotected) of bacteria proliferation within the PVA scaffold. Results are also compared with the most widely used method for cells colonization of scaffolds; i.e., soaking of a preformed PVA scaffold in bacteria culture medium.