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Die Hysterese der Adsorptions‐ und Desorptionsisothermen an porösen Silicagelen und Aluminiumoxiden
Author(s) -
Kohlschütter Hans Wolfgang,
Lüscher Madeleine,
Signer Rudolf
Publication year - 1974
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19740570206
Subject(s) - chemistry , hysteresis , desorption , mesoporous material , adsorption , volume (thermodynamics) , amorphous solid , sintering , precipitation , phase (matter) , differential thermal analysis , mineralogy , analytical chemistry (journal) , chemical engineering , thermodynamics , chromatography , crystallography , organic chemistry , meteorology , diffraction , optics , engineering , physics , quantum mechanics , catalysis
In selected groups of amorphous silica gels and finely crystalline aluminium oxides, hysteresis loops between the adsorption‐ and desorption isotherms of water were determined. The total volumes of the pore systems were analysed with the aid of the differential quotients of the hysteresis loops. In the group of silica gels relationships will be demonstrated between the precipitation of polysilicid acids and the distribution of the pore volume in the xerogels. In the group of aluminium oxides the influence of sintering at high temperatures on the distribution of the pore volume will be described. The hysteresis loops and especially the differential quotients distinctly differentiate specific properties of the used materials with their variables pore systems. An apparatus was used which recorded weights of water (= volumes and volume differences) with high sensitivity over the entire range p/po = 0 to 0,95. The appearance of hysteresis according to the fundamental theory was a sign that in this range adsorption and desorption of the liquid phase water took place in mesopores.