A new generation of "molecular basket" sorbents (MBS) has been developed by the optimum combination of the nanoporous material and CO(2)/H(2)S-philic polymer sorbent to increase the accessible sorption sites for CO(2) capture from flue gas (Postdecarbonization), and for CO(2) and H(2)S separation from the reduced gases, such as synthesis gas, reformate (Predecarbonization), natural gas, coal/biomass gasification gas, and biogas. The sorption capacity of 140 mg of CO(2)/g of sorb was achieved at 15 kPa CO(2) partial pressure, which shows superior performance in comparison with other known sorbents. In addition, an exceptional dependence of MBS sorption performance on temperature for CO(2) and H(2)S was found and discussed at a molecular level via the computational chemistry approach. On the basis of the fundamental understanding of MBS sorption characteristics, an innovative sorption process was proposed and demonstrated at the laboratory scale for removing and recovering CO(2) and H(2)S, respectively, from a model gas. The present study provides a new approach for development of the novel CO(2)/H(2)S sorbents and may have a major impact on the advance of science and technology for CO(2)/H(2)S capture and separation from various gases.

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Adsorbents based on transition metal ion-exchanged Y zeolites (with Cu, Ni, Zn, Pd, and Ce ions) were synthesized and evaluated for the adsorptive desulfurization of a model jet fuel (MJF) and a real jet fuel (JP-8). Among the adsorbents tested, Ce-exchanged Y zeolites exhibited better adsorption capacity of about 10 mg of sulfur/g of adsorbent at 80 °C with a MJF containing 510 ppmw sulfur. The same adsorbent exhibited a sulfur adsorption capacity of about 4.5 mg/g for the real JP-8 jet fuel containing about 750 ppmw sulfur. Desulfurization of MJF under flow conditions at 80 °C showed a breakthrough capacity of about 2.3 mg/g of adsorbent. Ce-exchanged zeolites exhibited higher selectivity for sulfur compounds as compared to the selectivity of aromatics, for which a comparative study indicated that the sulfur compounds are adsorbed over Ce-exchanged Y zeolites via direct sulfur−adsorbent (S−M) interaction rather than via π-complexation. While the selectivity for 2-methyl benzothiophene (2-MBT) was higher in the static adsorption studies, the adsorption selectivity decreased in the order 5-methyl benzothiophene (5-MBT) > benzothiophene (BT) > 2-MBT under dynamic conditions. This trend was correlated to the electron density on sulfur atoms derived from computer-aided molecular orbital calculations.

This work focuses on characterizing the structural and surface properties of Ti X Ce 1-X O 2 (TiO 2 -CeO 2 ) mixed oxides using XRD, XPS, BET, H 2 -TPR, and NH 3 -TPD techniques. The Ti X Ce 1-X O 2 mixed oxides synthesized by the urea coprecipitation method showed unimodal nanoporous structure with pore sizes increasing from 3.7 nm for X ) 0.9 to 5.3 nm for X ) 0.1. Concomitant with their higher surface area and pore volume, the mixed oxides were nanocrystalline, about 4.0 nm in crystallite size when X ) 0.9, and 4.8-5.4 nm when X ) 0.1-0.3, which are significantly smaller than TiO 2 and CeO 2 single oxides prepared by the same method (8.1 to 8.4 nm). A dominant anatase phase was detected by XRD when X was 0.9 or higher while a cubic fluorite phase was dominant when X was 0.3 or lower. Lattice parameters were changed by incorporating Ce into TiO 2 , and Ti into CeO 2 , respectively. This change indicates distortion of structure and was attributed to reduction of Ti 4+ to Ti 3+ , and Ce 4+ to Ce 3+ . XPS (Ce 3d, Ti 2p, O 1s) and H 2 -TPR revealed that the oxidation state of surface cations decreased, and oxygen deficiency of the surface was significantly enhanced by introducing Ce into TiO 2 , and Ti into CeO 2 . The structural and surface modification by introducing Ce into TiO 2 increased the reducibility of mixed oxides in H 2 -TPR. NH 3 -TPD showed that increasing Ti content in Ti X Ce 1-X O 2 enhanced surface acidity. Furthermore, H 2 O and N 2 formation from NH 3 was detected by mass spectrometry, which was attributed to the oxidation activity of the Ti X Ce 1-X O 2 mixed oxides. The highest NH 3 oxidation activity was observed when X ) 0.9. The present study clearly established that the structural (crystal phase, crystal size, nanoporosity, pore size) and surface properties (reducibility, oxygen deficiency, acidity, oxidation activity) of the Ti X Ce 1-X O 2 mixed oxides can be tailored by controlling their composition by the urea coprecipitation procedure.