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New liquid absorbents (LA) consisting of water solutions of CO 2 -complexing agents have been developed and tested in an experimental lab-scale to be used in CO 2 separation from gas mixtures. The results here presented concern the preparation of these amino acid based new liquid absorbents and the studies carried out to determine their performance as CO 2 scrubbers. The novel systems show good performance in terms of sorption and stability compared to the standard alkanolamines. Moreover, the experimental results have shown that among the studied carriers, arginine and ornithine are the natural amino acids with greater affinity towards CO 2 and that some of the here synthesized amino acids show outstanding absorption capacities, superior to MEA or any other amino acid tested. The developed materials have a direct use as mobile carrier membranes for facilitated transport and present a great potential for application in gas separation processes. Computational (DFT) and spectroscopic ( 1 H and 13 C-NMR) methods have been applied to make clear the mechanism of carbamate formation from the amine group of amino acids and CO 2 .

A dynamic model of small valveless pressure swing adsorption (PSA) and vacuum and pressure swing adsorption (VPSA) units for the production of oxygen was developed for the purpose of simulation and optimization. This valveless operation, very often used in commercial units, results in a more complex cycle than the classic Skarstrom cycle, differing in the optimization conclusions and presenting specificities that cannot be ignored in the modeling and simulation. Three different commercially available adsorbents were evaluated for use in these units: Oxysiv 5 and Oxysiv 7 from UOP and SYLOBEAD MS S 624 from Grace Davison. The units' performances (product recovery and power consumption) using each adsorbent were compared for cycles with the same pressure ratio. The simulation results were found to be in agreement with experimental results obtained on a commercial unit.