GB2257982A

GB2257982A - An electrolytic method of drinking-water purification

Info

Publication number: GB2257982A
Application number: GB9115964A
Authority: GB
Inventors: Vitold Mikhailovich Bakhir; Yuri Georgievich Zadorozhni
Original assignee: KIRK AND Co INTERNATIONAL
Current assignee: KIRK AND Co INTERNATIONAL
Priority date: 1991-07-24
Filing date: 1991-07-24
Publication date: 1993-01-27
Anticipated expiration: 2011-07-24
Also published as: GB2257982A8; GB9115964D0; GB2257982B

Abstract

Water is made to flow through the anode chamber 1 of a diaphragm electrolyser having an ultra filtration diaphragm 4, then through a body 8 of carbon granules and finally through cathode chamber 3. Electricity consumption is from 100 to 1500 coulombs per litre depending on requirements. The anodal processing achieves complete decontamination, destructive oxidation of organic contaminants, viz. phenols, formaldehyde, phosphororganic, metal-organic and serous compounds. The destructive oxidation products are non-toxic. They include water, carbonic acid gas, carbonic acids and other harmless substances. The cathodal processing achieves hydrolytic disintegration of organic impurities, viz. amino compounds, nitrils, certain phosphororganic insecticides, neutralisation of heavy-metal ions - lead, mercury, selenium, chromium and others, loosening of the structure of water, and enhancement of its biological qualities. The substances produced by hydrolytic reactions of organic compounds are non-toxic. <IMAGE>

Description

AN ELECTROLYTIC METHOD OF DRINKING-WATER PURIFICATION The Invention provides an electrolytic method of removing microorganisms, harmful organic substances and heavy-metal ions from drinking water.

One method of electrolytic purification using a diaphragm electrolyser exists under British Patent no.1173258, whereby the water which is processed in the anode chamber becomes a bactericide with increased acidity, whilst the content of harmful organic substances, e.g. phenols, is diminished. Water which is processed in the cathode chamber becomes alkaline, and both neutralises heavy-metal ions and binds them in indissoluble water with a neutral pH value. Another existing method, under U.S. Patent no.3910829, uses a hydraulic flow system consisting of three diaphragm electrolysers connected in series. This method is used for decontaminating water and is based on processing the water in the cathode chamber of the first diaphragm electrolyser, followed by anodal processing in the other two.The water thus processed contains a high level of anodal oxidation products and, while it is completely decontaminated, it does not have the properties of high-quality drinking water. Apart from this flaw in the method, it requires an elaborate system of diaphragm electrolysers which need precise coordination with the aid of automatic control devices. This complicates its operation.

The present Invention achieves complete decontamination of water, removal of organic substances by means of anodal oxidation, and neutralisation of heavy-metal ions. It leaves no residue of anodal oxidation products or active chlorine. The principle of this Invention is explained by the hydraulic-flow diagram in Fig. 1.

The initial water, containing microorganisms, organic contaminants, heavy-metal ions, enters anode chamber I of the diaphragm electrolyser 2. As it passes through anode chamber I, active chlorine is formed from the salts which are present in any ordinary drinking water. The combination of active chlorine (C10-, HC10, Cl2) and also ozone, oxygen and free radicals C1, O, HO2 and others, which form on the anode, completely destroy all microorganisms in the water.They oxidise organic impurities, e.g. phenols:

formaldehyde: HCHO + 20H- - 2e kH2 + C02 + H20, phosphororganic, metal-organic and serous compounds, whilst forming non-toxic and harmless substances, including water, carbonic acid gas, carbonic acids and other substances which are always present in the human body. Anodal processing removes all unpleasant odours from the water. The water pressure in anode chamber I is greater than the pressure in cathode chamber 3, therefore a very small proportion of the water from the anode chamber percolates through the hard ultra-filtration diaphragm 4 into the cathode chamber.This greatly slows down the formation of hydroxides of alkali-earth metals in the pores of the diaphragm and enables a constant electrical resistance to be maintained between anode 5 and cathode 6 for a prolonged period. Also, the small amount of H+ ions which pass from the anode to the cathode chamber have a positive effect on the purified drinking water by stabilising the concentration of free hydroxide ions at the optimal level. As it leaves anode chamber I of electrolyser 2 the water enters container 7, which is filled with a hard porous carbon material 8, such as granules of pure graphite.On the surface of this material active chlorine is broken down in the following reactions: 2HC10 + C w2HCl + CO2, 2 C12 + 2H20 + C CO2 + 4HC1 Whilst active chlorine is necessary for neutralising the activity of microorganisms, it is harmful to the human body as well as to microbes. The reactions occurring in container 7 leave the water sterilised and safe to drink, and at the same time pleasant to taste. The water is then introduced into cathode chamber 3 of electrolyser 2, where direct electrolytic reduction (on the surface of cathode 6) of certain organic impurities,.e.g.

amino-compounds and nitrils, takes place, together with their hydrolytic disintegration.

Ions of heavy metals - copper, zinc, nickel, lead, mercury and others - are transformed into neutral atoms or inactive hydroxides, and become non-toxic since they do not enter into biochemical reactions as oxidants. In cathode chamber 3 the structure of the water is broken down, and the redox potential is changed to a level equivalent to that inside the human body. The biological quality of the water is enhanced, especially its ability to penetrate the biological membranes of cells and to assist metabolic processes. The Invention transforms undrinkable water with varying degrees of impurity into pure drinking water.

The required degree of electrolytic processing is obtained by varying the electrical current input. Most natural water requires between 100 and 1500 coulombs per litre.

The upward passage of water in the electrode chambers 1 and 3 of electrolyser 2 facilitates even mixing and maximum interaction of each unit of water with the electrodes, with constant gas-release on their surfaces. The maximum contact of the water with the surface of the hard porous carbon material is achieved by the downward flow of the gas-liquid. These optimally effective flows are produced in each of the three main elements of the hydraulic flow-route shown in Fig. 1: the electrode chambers 1 and 3 of electrolyser 2 (upwards) and container 7 (downwards), which is filled with hard porous carbon material 8.

Claims

We claim a technique for processing drinking water electrolytically in a water-tight enclosed flow-type system. The system comprises a diaphragm electrolyser with a hard ultrafiltration diaphragm, and a container filled (or partly filled) with carbon material. Water is made to flow through the anode chamber of the diaphragm electrolyser, then through the body of hard porous carbon material in the container, and finally through the cathode chamber of the device; simultaneously the water flowing from the anode chamber into the cathode chamber via the diaphragm undergoes ultrafiltration, with electric current flowing between the elecrodes of the device which causes processing of the water in both electrode chambers at a current volume of between 100 and 1500 coulombs per litre. The movement of the water in the electrode chambers of the device is upwards, while through the carbon container it flows downwards.