Self-regulation of iron ion concentration in hydrated porous glasses

C. Choi, H. Haranczyk, K. G. Soga, R. J. Rumm, M. M. Pintar

Research output: Contribution to journalReview article

6 Scopus citations

Abstract

The water proton spin-lattice relaxation rate was measured in Fe contaminated water filled porous glasses with pore diameters of 548 and 2917 Å at 0.65T at room temperature as a function of pore hydration. Two distinct regimes could be defined. A "wet" pores regime (0.6<V0/V<1) and a regime with water only within the pores (1<V0/V<4), where V0 is the pore volume and V the water volume. In both regimes, the proton relaxation rate varies linearly with V0/V. A small Fe ion concentration in porous silica glass water remains constant while the hydration of pores is changed by a factor of ≈4, which is a necessary assumption to model the observed proton spin-lattice relaxation rate. Such a constant small concentration premise agrees with the Langmuir isotherm, which for systems with large surface to volume ratios (S/V0), predicts a constant small volume concentration. In the two studied porous glasses with S/V0 of 9.2×106 and 42×106 m-1, the condition for large S/V0 was satisfied, while the Fe volume concentration which was ∼1 mM was small, as required. An analysis of the paramagnetically enhanced proton relaxation is presented.

Original languageEnglish (US)
Pages (from-to)5861-5865
Number of pages5
JournalJournal of Applied Physics
Volume80
Issue number10
DOIs
StatePublished - Nov 15 1996

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Choi, C., Haranczyk, H., Soga, K. G., Rumm, R. J., & Pintar, M. M. (1996). Self-regulation of iron ion concentration in hydrated porous glasses. Journal of Applied Physics, 80(10), 5861-5865. https://doi.org/10.1063/1.363579