Molecular Diffusion and DNP Enhancement in Aqueous Char Suspensions |
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| Authors: | BM Odintsov RL Belford PJ Ceroke ZSh Idiyatullin RS Kashaev IV Kuriashkin VS Rukhlov AN Temnikov RB Clarkson |
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| Institution: | aIllinois Research EPR Center,;eDepartment of Chemistry, and;bDepartment of Veterinary Clinical Medicine, University of Illinois, 190 MSB, 506 S. Mathews, Urbana, Illinois, 61801;cState Technological University;dZavoiski Physical-Technical Institute, Russian Academy of Sciences, Kazan, 420029, Russia |
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| Abstract: | The heterogeneous1H dynamic nuclear polarization (DNP) effect is studied at low magnetic fields for a system consisting of several newly synthesized carbon chars suspended in water. By using Fourier Transform pulsed-field-gradient spin–echo NMR spectroscopy, several different self-diffusion coefficients have been observed in aqueous char suspensions, corresponding to regions of differing water mobility in the porous structure. Proton spin–lattice relaxation data generally confirm the results of molecular diffusion measurements. Through utilization of the Torrey model, the influence of “cage effects” on DNP enhancement in porous media is discussed. Results suggest that short-range nuclear–electronic interactions in pores have a dominant effect on DNP enhancement in char suspensions. |
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| Keywords: | surface&ndash liquid interactions DNP NMR |
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