Functional water, as the name suggests, is an emerging technology that gives water a specific performance. There is no strict and clear definition of functional water. Generally speaking, it refers to water in its natural state or after artificial treatment that has a higher energy level than ordinary water, which is called "living water", and active water made by artificial treatment for different purposes is called "functional water". Japanese functional water expert, Prof. Fujita, has given a more rigorous definition of functional water: (1) water itself or (2) trace mixtures contained in the water, under certain conditions (electrolysis, electric field, additives, high temperature and high pressure), presenting its own excellent potential characteristics, so that the water to achieve a particular situation (interrupting the hydrogen bonding, change the acidity and alkalinity, ORP), or to achieve some noteworthy purpose ( Corrosion prevention, scaling.... etc.). This newly discovered water is called functional water. For example, water molecule clusters (Cluster) and supercritical water belong to category (1), while some limited-life active seeds and metal ions belong to category (2).
Before discussing the theme of this article, "Electrolytic Water", in order to enable readers to have an overall understanding of functional water, I would like to firstly describe the classification and application of functional water as follows.
Currently on the market in a variety of functional water manufacturing or application technology, can be broadly divided into three categories: (1) external water quality control technology, (2) water filtration technology, (3) water processing technology, and its application throughout the industry, people's livelihoods, and its classification as listed in Table 1.
Comprehensive Table 1 lists a variety of water quality control and processing technology, the purpose of which is to change the nature of the treated water, to achieve a more special performance of the active water. Due to the wide variety of functional water types and technologies, some of these technologies remain in the commercial publicity of the manufacturers themselves, and are limited to the limits of current detection instruments, the principles and effectiveness of which have yet to be verified. Electrolyzed water is one of the most widely used and mature manufacturing technologies.
One, the use of
Electrolyzed water according to its electrolysis is divided into diaphragm type and no diaphragm type, according to its role can be divided into strong electrolytic water and weak electrolytic water. The water produced by electrolysis is divided into two streams, acidic water and alkaline water, each with different uses. They can be roughly distinguished as follows:
1. Alkaline ionized water (pH=9~11):
According to the manufacturer's recommendations, it is mainly used for drinking raw water, relieving hangovers, brewing tea, coffee, mixing wine, brewing powdered milk, cooking, cooking water, washing vegetables, and watering plants, etc.
The Japanese government has also developed a new generation of alkaline ionized water.
There are medical institutions in Japan that use alkaline ionized water as a substitute for normal drinking water for patients. Its claimed therapeutic effects include: treatment of gastrointestinal discomfort, constipation, dysentery, diabetes, high blood pressure, and improvement of physical fitness. Domestic scholars have also pointed out that alkaline ionized water can eliminate free radicals in the human body (free radical)4 (free radicals, containing unstable unpaired electrons, too much can destroy the body's lipids, and even finally make the cells mutate and produce cancer).
In the electronics industry, NEC Corporation proposed to use alkaline ionized water to clean the surface of dicing wafers in 1994, which is more effective in removing dust particles than the ammonia used in general, and reduces the use of chemicals and the cost of wastewater treatment.
▲ Table 1 Classification and application of functional water
2. Acidic ionized water (pH=5~2.5):
Weakly acidic ionized water can be used as an astringent for the skin, which is claimed to have a cosmetic effect, and it can also be used for cleaning utensils and wiping furniture, etc. Hyper-acidic water with a pH value of less than 2.5 has a sterilizing function, and in Japan there are medical institutions that use hyper-acidic water to disinfect wounds, sterilize wounds, and so on. In Japan, some medical organizations use super-acidic water to disinfect wounds and sterilize. In agriculture, there are examples of using super acidic water as a substitute for pesticide sterilization, and then using alkaline water to improve the pH value of the soil. In Japan, NEC and Organo have developed an acidic ionized water system to clean the surface of wafers from residual metal ions, which reduces the amount of chemicals used.
Generally speaking, weak electrolytic water is mostly used for drinking, food cleaning and soaking, and disinfection of human or animal contact, etc. Strong electrolytic water is used for disinfection and cleaning of industrial and medical equipment. Japan is the country where electrolytic water is most commonly used, and there are a lot of electrolytic water machines for various models and purposes. There are nearly 40 electrolytic water machine manufacturers and sellers, and there are 13 related research groups and organizations. As early as 1965, the Ministry of Health and Welfare of Japan approved the manufacture of electrolytic water generator as a medical device and recognized its therapeutic effect on gastrointestinal diseases. Currently, there are more than 400 units sold throughout Japan, with a penetration rate of about 8%, and there is a considerable amount of literature on the therapeutic efficacy of electrolyzed alkaline water and the application of electrolyzed acidic water for sterilization in the Japanese medical community. In addition, there are about 30 strong electrolytic water manufacturers and sellers, and the sales volume of 1994~1996 is 1000~3000 units/year, and the sales volume is 2~5 billion yen/year, and 70% of them are for medical use, and the other 30% are distributed in food, kitchen and agriculture.
▲Table 2: Manufacturers of Electrolytic Water Dispensers
▲Table 3: Publications on Electrolytic Water Dispensers
Electrolytic water dispensers are now more widely used in Taiwan, but the general public can also find bottled electrolytic water dispensers in general stores, which are mainly for health care purposes. Currently on the market there are about 10 kinds of brands of electrolytic water dispensers for sale, most of which are imported from Japan, and there are 2~3 kinds of domestic ones (see Table 2), and there are also some books published by academics to explain the therapeutic effect of electrolytic water, see Table 3.
In recent years, there are some manufacturers in the industrial sector (e.g., Organo) who have proposed to use electrolytic water instead of the traditional pharmaceutical solutions for cleaning wafers, electronic materials, etc. However, this technology is not yet common. However, this technology is not yet common, its equipment and operating costs are not competitive, the advantages of 1. can reduce the use of hazardous chemicals. 2. indirectly reduce the cost of wastewater treatment. 3. reduce labor due to exposure to hazardous chemicals caused by occupational injuries, disasters. 4. easy to operate, reducing manpower.
Agriculture and animal husbandry are examples of using electrolytic acidic water for sterilization and electrolytic alkaline water for watering and feeding.
The application of electrolyzed water is mostly concentrated in Japan, including hospitals, agriculture and animal husbandry. Many hospitals have installed electrolytic water dispensers for chronic patients to drink and improve their health, as well as using electrolytic acidic water to disinfect wounds, etc. Dentists use electrolytic acidic water to rinse instruments and sterilize patients' mouths. The following are two examples.
Tokyo Medical and Dental University Hospital, in March 1999 in the exclusive kitchen of its wards, the installation of electrolytic hypochlorite water supply system, the disinfection water used before the installation of this equipment is manually prepared sodium hypochlorite solution, used to disinfect the washing of fruits and vegetables and the patient's used tableware, the floor after cleaning is also used to electrolytic hypochlorite water disinfection, the cost of the equipment, including water supply piping and construction * * * * 15 million yen. The newest addition to the lineup is a new, more compact design, which allows users to easily and efficiently use the power of their PCs to power up their PCs, and to use the power of their computers to power up their PCs.
▲Table 4: Comparison of electrolyzed alkaline water and sodium hypochlorite solution
▲Table 4: Comparison of electrolyzed alkaline water and sodium hypochlorite solution
In terms of animal husbandry, there are 27 farms in Hokkaido that use electrolyzed alkaline water as a substitute for tap water for drinking by dairy cows, and the health of cows is observed by a group of veterinarians, and they have come up with the following conclusions:
1. 18~28%.
2. Reduced fecal odor.
3. Decrease in dysentery.
4. Increased appetite.
5. Increase in reproduction rate, decrease in stillbirths, etc.
▲ Figure 1 Pourbaix diagram of water
The principle
Electrolyzed ionized water is to change the pH and redox potential of water by electrolysis and decompose it to produce O2 and H2. Generally speaking, the chemical reaction that can increase the free energy does not exist. Therefore, it is impossible for water to decompose and produce O2 and H2 in its natural state, but if a cathode and anode are added to the water and the current is passed on, an electrolysis reaction can occur according to Faraday's law. The anode is usually made of platinum or graphite, which is not easily dissolved. In the anode and cathode redox reaction is as follows:
2H2O + 2e-= 2OH- + H2 alkaline ionized water with reducing power
E0=0-0.0591pH
H2O= 2H+ + 1/2O2 + 2e- acidic ionized water with oxidizing power
E0=1.228-0.0591pH
After the generation of hydrogen and oxygen on the surface of the cathode and anode, the water around the electrode will tend to be acidic and alkaline, and the redox potential will change, as shown in Figure 1. The porous semi-permeable membrane inserted between the two electrodes can restrict the water transfer, or allow anion and cation to selectively pass through the anion and cation semi-permeable membrane, i.e., from the anode to collect the acidic water with high concentration of hydrogen ions and oxidizing power, and from the cathode to collect the alkaline water with high concentration of hydroxyl ions and reducing power, as shown in Fig. 2, which is the internal structure of the commercially available products and the principle of manufacturing.
▲Figure 2: Ionized water internal structure reference chart
The cathode and anode of the ionized water is not unified, the electrolysis of acidic water is also known as electrolysis of oxidized water, electrolysis of alkaline water is electrolysis of reduced water, this paper for the sake of unity, all said electrolysis of acidic water, electrolysis of alkaline water.
Three, performance verification
1. Analysis of the composition of electrolyzed water
Reasonable explanation of the effectiveness of electrolyzed water before the first must understand the basic water quality data of acidic water and alkaline water, Japan Kurita Industry (Ltd.) Research and Development Headquarters to the local tap water mixed with sodium chloride as an electrolyte to observe the different electrolysis time, acidic and alkaline water water quality changes in the situation as shown in Table 6, Figure 3, and the water quality of the alkaline water, the water quality of the alkaline water.
▲Figure 3 Relationship between electrolysis time and composition of electrolyzed water
▲Table 6 Composition of electrolyzed water with different electrolysis time
▲Table 7 Comparison of electrolyzed hypochlorite water and sodium hypochlorite solution
The pH of acidic water is inversely proportional to the electrolysis time, while the ORP, electrical conductivity, and concentration of chlorine ions are proportional to the ORP, and the increase of chlorine ions might enhance the oxidizing power of acidic water. The increase of chlorine ions may enhance its bactericidal power, on the contrary, the reducing power of alkaline water is strengthened with the decreasing of ORP.
There is another theory that compares the NMR (Nuclear Magnetic **** vibration) O17 spectrum of raw water and electrolyzed water, and finds that the half-height width of electrolyzed water is smaller than that of raw water, which means that the water molecule group of electrolyzed water (cluster) is smaller than that of raw water.
Table 7 is a comparison of the composition of electrolyzed water and raw water.4 In addition to the aforementioned differences in pH and redox potential, there are also differences in trace elements.
2. Efficacy
Most of the uses of electrolyzed alkaline water are for drinking, planting, etc., and its efficacy is more difficult to quantify, and each individual's different physical condition also makes its efficacy uncertain. It is reasonable to say that alkaline water can eliminate (restore) excess free radicals in the human body, reduce oxidation in the body, in other words, reduce the possibility of carcinogenicity, which has yet to be verified by the medical profession's collaborative research. In terms of plant watering, there is a Japanese literature comparing the results of planting sprouts with tap water and electrolyzed water, and the difference is not significant.5 However, it is questionable that each plant does not have the same requirements for water quality, and a more rigorous approach would be to consult a horticulturist or botanist to select several plants with different properties for comparison. The following are three examples of the practical application and results of electrolysis of acidic and alkaline water.
● Bactericidal power 3:
Electrolysis of acidic water is added to the tap water in a specified concentration of sodium chloride (NaCl), and electrolyzed to produce. In the control group, sodium hypochlorite (NaOCl) solution and hydrochloric acid were added to the tap water and adjusted to the same hypochlorite concentration and pH as the electrolyzed acidic water. The results of this study are shown in Table 8, which demonstrates that the bactericidal effect of acidic water electrolysis can be attributed to the lower pH value of the hypochlorite solution.
▲Table 8: Results of CFU measurement
▲Figure 4: Comparison of dust particles removal effect after CMP
● Golf course:
A golf course in Japan has used electrolytic acidic water to spray on the lawn to sterilize the grass for 3 years, the electrolytic solution is 0.8% potassium chloride solution, and the amount of spraying is usually 1L/m2 of acidic water (sterilizing) and alkaline water (potassium chloride) that is dispersed once a week interactively. with alkaline water (potash). The results of the field survey found that the electrolysis of acidic water does not have the problem of pharmaceutical residues and can save 70~80% of fungicides and insecticides, but it is not effective for weed control and the equipment is expensive, so the economic benefits are not competitive. The author suggests that the use of sodium hypochlorite solution and hydrochloric acid can be deployed in the same conditions of the solution, the cost of equipment is not only cheaper than the electrolysis method, the storage and operation of drugs, etc., than the electrolysis method of manufacturing acidic water to be easier and safer. However, the author believes that from the long-term viewpoint of environmental protection, saving chemicals and no chemical residues of the problem of the electrolysis method is superior.
● Wafer cleaning (wafer):
NEC proposed in 1994 to electrolysis alkaline water instead of ammonia, can be more effective in removing dust particles (particles), as shown in Figure 4. Due to the electrolysis of alkaline water (cathode water) is rich in OH- ions, and its ionic strength is small, with electrochemical reduction, so than the general alkaline water solution of the dust particles removal effect is good.
Fourth, the future outlook
Modern society, science and technology is becoming more and more complex and diversified. When considering the development of a new technology, in addition to the basic functional requirements, the cost of equipment, routine maintenance, the impact on society and the natural environment should also be an overall assessment, that is, product life cycle assessment. The application of electrolyzed water in all aspects, the main advantages are: 1. reduce the use of chemicals. 2. no residual effects, environmental pollution problems. If we can really master the operating conditions to increase its reproducibility, to replace the current high pollution of water, the scope of its development will be unlimited.
Currently, the cost of electrolytic water treatment equipment for industrial and agricultural use and the operating costs are high, and it is not yet possible to compete with the traditional treatment method. However, in the context of environmental protection and labor safety, the industry has begun to face two major problems: 1) wastewater, waste pharmaceuticals, and waste water that can be disposed of nowhere else, or the cost of disposal is much higher than the current problem. 2) the dumping of drinking water from Kaohsiung County, which is now the largest drinking water source in the world. The recent dumping of toxic organic solvents in Kaohsiung County's drinking water source highlights this serious problem, and the most direct solution is to try to reduce the amount of toxic chemicals. 2. Operator safety concerns and shortening of working hours, increasing labor costs. Electrolysis of water used in non-toxic agents and cheap and easy to obtain, the output of water without pharmaceutical residues, can make up for the above shortcomings, the future should be able to gradually replace the traditional way to become the mainstream, then due to the high demand for equipment and its own improvement, electrolysis equipment and operating costs are expected to be lowered to the extent of the competitive range.
This article only describes electrolytic ionized water in detail, which is like the tip of the iceberg for many types of functional water, but it also means that there is still a lot of room for effort in the field of functional water. As far as electrolytic water is concerned, it can be seen from human body drinking, cleaning, cooking, disinfection to high-tech industrial water. In the future, if there are more application examples and with the establishment of verification methods and reaction mechanisms, the use of electrolytic water may be able to solve some of the problems that are currently unattainable.