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624 results on '"Thallapally, Praveen K."'

206. Nanoparticles for biomedical imaging

Author

Nune, Satish K, primary, Gunda, Padmaja, additional, Thallapally, Praveen K, additional, Lin, Ying-Ying, additional, Laird Forrest, M, additional, and Berkland, Cory J, additional

Published
2009
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220. Hydrophobic pillared square grids for selective removal of CO2 from simulated flue gas.

Author

Elsaidi, Sameh K., Mohamed, Mona H., Schaef, Herbert T., Kumar, Amrit, Lusi, Matteo, Pham, Tony, Forrest, Katherine A., Space, Brian, Xu, Wenqian, Halder, Gregory J., Liu, Jun, Zaworotko, Michael J., and Thallapally, Praveen K.

Subjects
CARBON sequestration, HYDROPHOBIC compounds, FLUE gases, COAL-fired power plants, METAL-organic frameworks, X-ray diffraction
Abstract

Capture of CO2 from flue gas is considered to be a feasible approach to mitigate the effects of anthropogenic emission of CO2. Herein we report that an isostructural family of metal organic materials (MOMs) of general formula [M(linker)2(pillar)], linker = pyrazine, pillar = hexaflourosilicate and M = Zn, Cu, Ni and Co exhibits highly selective removal of CO2 from dry and wet simulated flue gas. Two members of the family, M = Ni and Co, SIFSIX-3-Ni and SIFSIX-3-Co, respectively, are reported for the first time and compared with the previously reported Zn and Cu analogs. [ABSTRACT FROM AUTHOR]

Published
2015
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243. Coordination Covalent Frameworks: A New Route for Synthesis and Expansion of Functional Porous Materials

Author

Elsaidi, Sameh K, Mohamed, Mona H., Loring, John S, McGrail, Bernard. Pete, and Thallapally, Praveen K.

Abstract

The synthetic approaches for fine-tuning the structural properties of coordination polymers or metal organic frameworks have exponentially grown during the past decade. This is due to the control over the properties of the resulting structures such as stability, pore size, pore chemistry and surface area for myriad possible applications. Herein, we present a new class of porous materials called Coordination Covalent Frameworks (CCFs) that were designed and effectively synthesized using a two-step reticular chemistry approach. During the first step, trigonal prismatic molecular building block was isolated using 4-aminobenazoic acid and Cr (III) salt, subsequently in the second step the polymerization of the isolated molecular building blocks (MBBs) takes place by the formation of strong covalent bonds where small organic molecules can connect the MBBs forming extended porous CCF materials. All the isolated CCFs were found to be permanently porous while the discrete MBB were nonporous. This approach would inevitably open a feasible path for the applications of reticular chemistry and the synthesis of novel porous materials with various topologies under ambient conditions using simple organic molecules and versatile MBBs with different functionalities that would not be possible using the traditional one-step approach.

Published
2016
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248. Separation of C 2 Hydrocarbons by Porous Materials: Metal Organic Frameworks as Platform.

Author

Banerjee, Debasis, Liu, Jun, and Thallapally, Praveen K.

Subjects
HYDROCARBONS, METAL organic chemical vapor deposition, POROUS materials, TORTUOSITY, DISTILLATION
Abstract

The effective separation of small hydrocarbon molecules (C1– C4) is an important process for the petroleum industry, determining the end price of many essential commodities in our daily lives. Current technologies for separation of these molecules rely on energy-intensive fractional distillation processes at cryogenic temperature, which is particularly difficult because of their similar volatility. In retrospect, adsorptive separation using solid-state adsorbents might be a cost-effective alternative. Several types of solid-state adsorbents (e.g., zeolite molecular sieves) were tested for separation of small hydrocarbon molecules as a function of pressure, temperature, or vacuum. Among different types of plausible adsorbents, metal organic frameworks (MOFs), a class of porous, crystalline, inorganic-organic hybrid materials, is particularly promising. In this brief comment article, we discuss the separation properties of different types of solid-state adsorbents, with a particular emphasis on MOF-based adsorbents for separation of C2hydrocarbon molecules. [ABSTRACT FROM AUTHOR]

Published
2015
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250. Simultaneous in SituX-ray Diffraction and Calorimetric Studies as a Tool To Evaluate Gas Adsorption in Microporous Materials

Author

Woerner, William R., Plonka, Anna M., Chen, Xianyin, Banerjee, Debasis, Thallapally, Praveen K., and Parise, John B.

Abstract

Combined application of in situX-ray diffraction (XRD) and differential scanning calorimetry (DSC) is a novel technique for rapidly evaluating the suitability of microporous materials for postcombustion CO2capture. Further, while many microporous materials show promise for CO2capture, most are not evaluated in the presence of water vapor, a major component of postcombustion flue gas. As a demonstration of the versatility of XRD-DSC techniques, representatives of the classes of materials typically proposed for CO2capture, zeolites, and metal–organic frameworks (MOFs) were studied: zeolite NaX, Ni-MOF-74 [Ni2(dobdc); dobdc = 2,5-dihydroxyterephthalate], ZIF-7 [ZIF: zeolitic imidazole framework, Zn(phim)2; phim: benzimidazole], and SBMOF-1 [Ca(sdb); sdb: 4,4′-sulfonyldibenzoate]. Although NaX and Ni-MOF-74 show very high affinity toward CO2under idealized dry conditions, they are also very sensitive to the presence of water vapor and experience significant performance loss above 25% relative humidity (RH) at room temperature. Relative to NaX and Ni-MOF-74, ZIF-7 and SBMOF-1 show strong CO2affinity even in the presence of 75% RH and may be more ideally suited for postcombustion flue gas CO2capture than compounds with unsaturated metal sites. XRD-DSC is particularly powerful for evaluating the consequences of framework flexibility, with XRD providing the signature indicative of the structural rearrangement and the DSC providing the enthalpies of adsorption for each structure. This kind of detailed energy evaluation is not possible with other noncalorimetric methods.

Published
2016
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