Pore Structure of Crystalline Ferric Hydroxides and Oxides

Water vapour sorption isotherms at 20 °C of two series of crystalline ferric hydroxide powders (α and γ) are reported. Samples of the α-series were prepared from synthetic crystalline α-ferric hydroxide by thermal decomposition at a fixed temperature between 25 °C and 350 °C. Samples of the γ-series...

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Main Author: A. Ruplis
Format: Article
Language:English
Published: SAGE Publications 1990-12-01
Series:Adsorption Science & Technology
Online Access:https://doi.org/10.1177/026361749000700405
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author A. Ruplis
author_facet A. Ruplis
author_sort A. Ruplis
collection DOAJ
description Water vapour sorption isotherms at 20 °C of two series of crystalline ferric hydroxide powders (α and γ) are reported. Samples of the α-series were prepared from synthetic crystalline α-ferric hydroxide by thermal decomposition at a fixed temperature between 25 °C and 350 °C. Samples of the γ-series were prepared from synthetic crystalline γ-ferric hydroxide in the same way. It has been found that water vapour sorption isotherms on α-series samples exhibit a reproducible closed hysteresis loop located at p/p0 = 0.3–0.8. Both the shape and the location of the hysteresis loop change as the decomposition temperature of the samples increases. Initially, the hysteresis loop seems somewhat parallel to the pressure axis but later it becomes perpendicular. To explain this phenomenon, a pore structure model is proposed whereby a system with slit-shaped pores changes into one with pores open at both ends.
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spelling doaj.art-144e06a67da246f6866660b36b2450842024-03-02T01:47:05ZengSAGE PublicationsAdsorption Science & Technology0263-61742048-40381990-12-01710.1177/026361749000700405Pore Structure of Crystalline Ferric Hydroxides and OxidesA. Ruplis0Riga Technical University. Dept. of Chemistry, 1 Kalku Street, 226355 Riga, The Republic of Latvia, USSR.Water vapour sorption isotherms at 20 °C of two series of crystalline ferric hydroxide powders (α and γ) are reported. Samples of the α-series were prepared from synthetic crystalline α-ferric hydroxide by thermal decomposition at a fixed temperature between 25 °C and 350 °C. Samples of the γ-series were prepared from synthetic crystalline γ-ferric hydroxide in the same way. It has been found that water vapour sorption isotherms on α-series samples exhibit a reproducible closed hysteresis loop located at p/p0 = 0.3–0.8. Both the shape and the location of the hysteresis loop change as the decomposition temperature of the samples increases. Initially, the hysteresis loop seems somewhat parallel to the pressure axis but later it becomes perpendicular. To explain this phenomenon, a pore structure model is proposed whereby a system with slit-shaped pores changes into one with pores open at both ends.https://doi.org/10.1177/026361749000700405
spellingShingle A. Ruplis
Pore Structure of Crystalline Ferric Hydroxides and Oxides
Adsorption Science & Technology
title Pore Structure of Crystalline Ferric Hydroxides and Oxides
title_full Pore Structure of Crystalline Ferric Hydroxides and Oxides
title_fullStr Pore Structure of Crystalline Ferric Hydroxides and Oxides
title_full_unstemmed Pore Structure of Crystalline Ferric Hydroxides and Oxides
title_short Pore Structure of Crystalline Ferric Hydroxides and Oxides
title_sort pore structure of crystalline ferric hydroxides and oxides
url https://doi.org/10.1177/026361749000700405
work_keys_str_mv AT aruplis porestructureofcrystallineferrichydroxidesandoxides