Browsing by Author "Sherrick, Jacob Leighty"

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    Adsorption by precipitates
    (1919) Sherrick, Jacob Leighty
    From the results of this investigation the order of adsorption of the ions by precipitated barium sulphate is: ferrocyanide > nitrate > nitrite > chlorate > permanganate > ferricyanide > chloride > bromide > sulphocyanate > iodide, the ferrocyanide ion being adsorbed the most and iodide the least. From a consideration of this order and of the absolute amount of adsorption in each case we find very little reason to place much credence in Schulze's law. Although we find a quadrivalent ion the most strongly adsorbed, we find four univalent ions more strongly adsorbed than the trivalent ferricyanide. Furthermore, contrary to what is implied in Schulze's law, we find a very wide variation in the amount of univalent ions adsorbed. This amount varies from 8.482 gram anions per 100 mols for nitrate to 0.056 gram anions per 100 mols for iodide ion. If the adsorption values are expressed in gram anions instead of gram equivalent anions the order becomes: nitrates > nitrites > chlorate > ferrocyanide > permanganate > chloride > ferricyanide > bromide > sulphocyanate > iodide, the nitrate ion being adsorbed the most and the iodide the least. Here there is nothing even to suggest Schulze's law.