Patent GB-402953-A (GB)
Title: Improvements relating to processes for the purification and/or sterilization of liquids by means of base exchangers
IPC: B01D15/04
Filed: 1933-01-19
Abstract: Liquids containing one or more salts in solution are purified or sterilized by passage through excess of a mass of mixed base exchangers containing two or two groups of different cations, the mass comprising elements or layers of composition varying gradually from one containing one or one group of cations alone to one containing the other or other group of cations alone, intermediate layers containing the two or two groups of cations in varying proportions.  Purification is effected by reaction between the mobile cations of the base-exchanger and the anions present in the liquid forming compounds such as insoluble or volatile salts that can be readily eliminated; and sterilization by reaction between the mobile cations and the anions producing solutions with a germ-killing action.  In one example, sea water is desalted by filtering through a mixture of lead or silver base-exchanger and sodium base-exchanger. Lead or silver chloride is formed and precipitated.  In the case of lead the base-exchanger may be regenerated by heating the wet systems or by injecting steam or hot water, since the lead chloride then goes into solution and again enters the base-exchanger.  Any soluble lead in the treated sea water may be removed by filtration through a small water softener.  In a second example, sugar juices or diluted molasses are caused to react with a mixture of potassium and calcium, barium, or aluminium base exchangers.  Thereby the phosphates, certain organic acids, a part of the nitrogenous matters and of the albuminoids and colouring matters are precipitated in combination with the calcium, barium, or aluminium cation.  Any barium remaining in solution in the treated and clarified juice may be removed by calcium sulphite or bisulphite, resulting also in further bleaching of the juice.  Chloride or sulphate of calcium remaining in the clarified juice may be removed by passage through a calcium-lead base-exchanger, lead sulphate and chloride being precipitated and the juice being further bleached.  Sugar juice which has been "chalked" in the usual way and then saturated with carbon dioxide, and contains calcium or potassium bicarbonates may be passed through a base-exchanger mixture, containing calcium, or calcium and potassium, and ammonium cations, with conversion of the bicarbonates to ammonium bicarbonate, which volatilizes when the juice is evaporated. Regeneration of the base-exchangers is effected by calcium, barium, aluminium, or ammonium salts, and the regenerating solution, after use, may be treated for recovery of potassium salts, for instance of potassium nitrate.  The phosphate-containing precipitates may be collected and used as fertilizers.  In a third example, a bacterially soiled water containing calcium sulphate is passed through a mixture of calcium, and silver, mercury, or cadmium base-exchangers.  The silver, mercury, or cadmium sulphate solution formed kills microbes and spores present, and the sterilized water is then passed through the base-exchanger in the reverse direction to regenerate the latter and remove from the water the silver &c. ion.  Water may be sterilized and softened in one operation by running it successively through a mixed base-exchanging mass containing calcium, magnesium, barium, and aluminium ions as a group and also mercury or silver ions, and then through a base-exchanger containing mercury or silver ions, and sodium ions. The base-exchangers may be regenerated by running through them successively in the reverse direction a solution of sodium chloride when mercury is present or of sodium nitrate when silver is present.  Reference is made also to the sterilization of wine, milk, and organic extracts.ALSO:Liquids containing one or more salts in solution are purified or sterilized by passage through excess of a mass of mixed base exchangers containing two or two groups of different cations, the mass comprising elements or layers of composition varying gradually from one containing one or one group of cations alone to one containing the other or other group of cations alone, intermediate layers containing the two or two groups of cations in varying proportions.  Purification is effected by reaction between the mobile cations of the base-exchanger and the anions present in the liquid forming compounds such as insoluble or volatile salts that can be readily eliminated; and sterilization by reaction between the mobile cations and the anions producing solutions with a germ-killing action.  In one example, sea water is desalted by filtering through a mixture of lead or silver base-exchanger and sodium base-exchanger.  Lead or silver chloride is formed and precipitated.  In the case of lead, the base-exchanger may be regenerated by heating the wet system or by injecting steam or hot water, since the lead chloride then goes into solution and again enters the base-exchanger.  Any soluble lead in the treated sea water may be removed by filtration through a small water softener. In a second example, sugar juices or diluted molasses are caused to react with a mixture of potassium and calcium, barium, or p  aluminium base-exchangers.  Thereby the phosphates, certain organic acids, a part of the nitrogenous matters and of the albuminoids and colouring matters are precipitated in combination with the calcium, barium, or aluminium cation.  Any barium remaining in solution in the treated and clarified juice may be removed by calcium sulphite or bisulphite, resulting also in further bleaching of the juice.  Chloride or sulphate of calcium remaining in the clarified juice may be removed by passage through a calcium-lead base-exchanger, lead sulphate and chloride being precipitated and the juice being further bleached. Sugar juice which has been "chalked" in the usual way and then saturated with carbon dioxide, and contains calcium or potassium bicarbonates may be passed through a base-exchanger mixture containing calcium, or calcium and potassium, and ammonium cations, with conversion of the bicarbonates to ammonium bicarbonate which volatilizes when the juice is evaporated. Regeneration of the base-exchangers is effected by calcium, barium, aluminium, or ammonium salts, and the regenerating solution after use may be treated for recovery, of potassium salts, for instance of potassium nitrate.  The phosphate-containing precipitates may be collected and used as fertilizers.  In a third example, a bacterially soiled water containing calcium sulphate is passed through a mixture of calcium, and silver, mercury, or cadmium base-exchangers.  The silver, mercury, or cadmium sulphate solution formed kills microbes and spores present, and the sterilized water is then passed through the base-exchanger in the reverse direction to regenerate the latter and remove from the water the silver &c., ion.  Water may be sterilized and softened in one operation by running it successively through a mixed base-exchanging mass containing calcium, magnesium, barium, and aluminium ions as a group and also mercury or silver ions, and then through a base-exchanger containing mercury or silver ions, and sodium ions. The base-exchangers may be regenerated by running through them successively in the reverse direction a solution of sodium chloride when mercury is present or of sodium nitrate when silver is present.  Reference is made also to the sterilization of wine, milk, and organic extracts.