GB432101A - Improvements relating to the sterilization of liquids - Google Patents

Abstract

Water and other liquids are sterilized by addition of liquid hydrogen peroxide or other non-gaseous oxygen-yielding substances other than halogen compounds together with one or more oligodynamically active metals or one or more compounds of such metals in oligodynamically minute quantities, in such manner that the actions of the two different agents can be separately controlled. The agents may be caused to act on the liquid simultaneously, or successively. Among the oxygen-yielding substances employed are peroxides, persalts such as persulphates, perphosphates, percarbonates and additive compounds of hydrogen peroxide with normal salts or with inert organic substances, e.g. perborate produced from borax and hydrogen peroxide, persulphate obtained by electrolysis of a potassium bisulphate solution, and calcium superoxide with sulphuric acid. The metals may be used in the form of their oxides or their difficultly soluble salts, e.g. silver oxide or chloride may be used, or in the form of their easily soluble salts. The metals and metal compounds act catalytically and decompose the oxygen-charged compounds. The metal may be introduced by inserting it as an anode in an electric circuit established through the liquid, or by atomizing it electrically in the liquid, or by producing a colloidal solution in the liquid by chemical or physical means. The liquid may be passed through a container filled with bodies of ceramic material coated with silver and after a time is drawn off and hydrogen peroxide solution is added to it, or these steps may be reversed. In other forms, predetermined quantities of hydrogen peroxide or a soluble persalt, &c. and of a soluble oligodynamic metal compound are dissolved in the liquid simultaneously or successively, or a colloidal dispersion or fine suspension of active metal or compound is produced in the liquid and then hydrogen peroxide or a persalt, &c. is added. A fine precipitate of silver chloride may be produced by adding silver nitrate and mixing if the liquid contains chlorides, and if there are absent sodium chloride solution or hydrochloric acid are added to produce the chloride. In another example, the oxygen-containing compound, e.g. hydrogen peroxide, is added to the liquid which is then passed through a vessel where it is exposed to a weak electric current between silver electrodes, the quantity of silver added to the liquid being controlled by adjusting the flow of the liquid and the strength of the electric current. One or both the active substances may be provided in measured quantities for addition to the liquid, e.g. made up separately or mixed in packets, tablets, pills, capsules or ampoules which may have indication of the contents stamped in them. The active material, e.g. a mixture of calcium peroxide with silver chloride may be enclosed in coverings which dissolve gradually or break up in the liquid so that they are freed only by degrees, e.g. by enclosing in gelatine capsules or in a crust of a crystalline substance which dissolves gradually in the liquid. One of the two active materials may be applied to insoluble carriers e.g. the wall of the container for the treatment or storage of the liquid or filling bodies which subdivide the liquid into a large number of cells. The liquids treated include mineral waters, lemonade syrups, must, beer, milk, vegetable extracts and medicines. The sterilized water may be used as a preserving and sterilizing agent for treating eggs, fruit, meat, vegetables, tobacco, medical instruments, cotton wool, wound dressings, wool, upholstering material, linen, &c. The liquid may be used as a disinfectant for human use. Specification 293,385, [Class 81 (i)], is referred to. The Specification as open to inspection under Sect. 91 comprises also the use in the process of metals, such as platinum, indium, gold and other precious metals, and iron, nickel, and cobalt, whose oligodynamic action is small, and their compounds, and also of oxygen-carriers generally. This subject-matter does not appear in the Specification as accepted.