Browsing by Subject "sorption."

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Access status: Open Access ,
Binarny charakter powierzchni węgla kamiennego
(2006) Kreiner, Krystyna; Żyła, Mieczysław
Actual views on structure of coal and chemical character of its surface, taking into consideration electron-donor and electron-acceptor centers, were reviewed. The influence of the character of surface layer together with its hydrophilic sites, which are responsible for wetting of coal, was demonstrated. The number of such sites fundamentally influences the number of adsorbed water molecules and it decreases with the C content in coal. The hydrophobic fragments present on coal surface are of great importance for sorption of vapours of both aliphatic and cyclic, non-aromatic hydrocarbons. Such hydrocarbons are connected with apolar fragments of coal structure by dispersion forces. During sorption of aromatic hydrocarbons, such as benzene and its alkyl derivatives, additionally to dispersion forces, interactions with phi electrons in aromatic rings must be taken into account. Adsorbates with both apolar groups, such as alkyl radicals, and polar groups, e.g. -OH and -COOH, cannot differentiate between hydrophilic and hydrophobic centers on coal surface.