The influence of salts on the adsorption of cupric ions by ferric hydroxide

Studies on Coprecipitation and Aging. XI. Adsorption of Ammonio Copper Ion on and Coprecipitation with Hydrous Ferric Oxide. Aging of the Precipitate.

“…The adsorption of copper follows the Freundlich adsorption isotherm. 5. Hydrous ferric oxide precipitated at 98°C.…”

“…It is the most interesting part of this study that we have shown this conclusion to be unwarranted. From the results in table 5 (third column) it is seen that the speed of aging of hydrous ferric oxide depends greatly upon the degree of alkalinity of the solution. A slow but pronounced aging occurs in 1 IV ammonia (aged in the absence of copper).…”

“…Aging experiments at room temperature Fresh precipitates of hydrous ferric oxide were aged under various conditions in the absence and sometimes in the presence of copper. With the exception of the first two experiments in table and the adsorption medium (without copper) were identical, the fresh precipitate of hydrous oxide was filtered after the precipitation, washed with water until the washings were chloride free (after about three hours continuous washing), and transferred into the aging medium given in the first column of table 5. When the aging medium was alkaline the suspension was kept in a paraffined bottle.…”

“…In order to get an indication as to which of the views was correct, the extractibility of the copper from the precipitates aged in the presence of copper (table 5) was investigated. After the periods of time indicated in table 5 the precipitates were washed with 1 N ammonia or a solution 1 N in ammonia and 1 N in ammonium chloride until the filtrates did not give a reaction with hydrogen sulfide or a xanthate solution.…”

The Removal of Silica from Water for Boiler Feed Purposes

“…On such a distinction probably most methods of silica removal are to be considered as adsorption methods (40,48,53,78,87). For example, the adsorptive properties of hydrous ferric oxide are well known (5,10,15,35,52,54,55,61,80,81,100,104,107). (1).…”