In recent years, with the improvement of living standards and some public events about water pollution, we are paying more and more attention to drinking water safety issues. According to the statistics of the national environmental department, 82% of China's rivers are polluted to varying degrees, and 50% of urban groundwater is polluted. Although many urban residents now have the habit of drinking pure water in barrels, they may experience a certain degree of secondary pollution because they have to go through many intermediate steps from the factory to the drinking. Therefore, many people will consider purchasing a household water purifier. However, the water purifier is not as common as traditional household appliances, and its use effect is hard to detect with the naked eye, so for consumers, how to purchase has always been a problem.
There are a lot of articles about water purifiers on the Internet that “encourage†some brand promotion information, which is difficult to evaluate. The following popular science articles, theories and data are collected from published papers or academic research results, will not mention any specific products, I hope to provide some reference for everyone to buy water purifier products.
Water purifier classification
The household water purifier first appeared in China in the 1980s. Its function is to filter the tap water of the city and remove harmful substances such as large particles of impurities, heavy metals and bacteria in the water. At present, there are common kitchen water purifiers, Faucet water purifiers, and portable desktop net water bottles. The first two purification objects are urban tap water, and the net water bottle is generally used to purify drinking water in the office.
The use of purified water products abroad is significantly different from domestic ones. For example, in Europe, there are more net water bottles, and desktop small water purifiers are also more common. Because the tap water quality in these countries has reached the standard of drinking, the use of water purification products is mainly to improve the taste. In China, tap water is not suitable for raw drinks, so it is not advisable to use tap water to purify tap water. In terms of purification effect, the kitchen type (including can be hung on the wall) is generally better than the faucet type, so in theory, the kitchen type water purifier is more suitable for daily use.
The principle of the water purifier
There are four main methods for water quality treatment. One is activated carbon-based medium filtration method (such as activated carbon/PP cotton filter), and the other is microfiltration, ultrafiltration, nanofiltration and reverse osmosis membrane separation. It is a physicochemical disinfection method based on sterilization (such as UV disinfection), and the fourth is a water quality regulation method based on softening and electrolysis. Which methods are used depends on the conditions of use. For example, the net kettle, because of its small size, is inconvenient to use ultraviolet light, electrolysis, etc., and can not generate enough pressure for membrane separation filtration, so the media filtration method is often used.
The following figure is an example. At present, the kitchen type water purifier generally combines the medium filtration method and the membrane separation method to form a filter element. Therefore, to evaluate the quality of a water purifier, mainly depends on the quality of the filter. The price difference between the water purifiers is also mainly from the filter element. The more the filter material is used, the more the number of filter layers, the better the purification effect.
In most cases, after the tap water enters the water purifier, it will first pass through the medium filter module in the filter element. At this stage, most of the suspended matter, odorous substances and large organic substances in the water are adsorbed by the medium such as activated carbon. However, studies have shown that activated carbon only has a significant removal effect on organic matter with a molecular weight of 500-3000, and has little effect outside this range. Therefore, water at this stage may also have residues of bacteria, viruses, and heavy metals. At this time, it was the turn of the membrane separation method.
We all know that a balloon full of gas will gradually become smaller even if there is no air leak. This is because there is a gap between the molecules, and the elasticity of the balloon will exert some pressure on the internal air, accelerating the internal air. Escaped. Membrane separation method can also be understood as follows. The membrane pores used for water purification are very small. Under the action of pressure, solvent (water) and quantitative solute (water impurities) can pass through the membrane, and the rest of the material is trapped on the other side. .
Main indicator of water purifier
The key is coming! What is the concept of reverse osmosis, microfiltration, and ultrafiltration seen when buying a water purifier? In fact, this is the name of the four membrane pore size membranes used in the membrane separation method. The complete classification is: microfiltration membrane (MF), ultrafiltration membrane (UF), nanofiltration membrane (NF) and reverse osmosis membrane (RO). The smaller the membrane pore size, the higher the filtration accuracy, the greater the working pressure, and the slower the passage speed.
The microfiltration membrane has a pore diameter of 0.05-5.00 μm, an operating pressure of 0.01-0.2 MPa, and can retain an example of 0.02-10 μm; an ultrafiltration membrane pore size of 5 nm-0.1 μm, an operating pressure of 0.1-1.0 MPa; Between reverse osmosis, high water throughput can be achieved at a pressure of 0.5-1.0 MPa; while the reverse osmosis membrane has a pore size of only 1-10 angstroms (one thousandth of a nanometer), which can almost remove water. All impurities, including various suspended solids, colloids, dissolved organic matter, inorganic salts, bacteria, microorganisms, etc., theoretically the water quality is infinitely close to pure water.
We went to the e-commerce website to find that the products with higher rankings were mainly reverse osmosis water purifiers and ultrafiltration water purifiers. Due to the high cost of reverse osmosis membranes, the price of reverse osmosis water purifiers is also generally expensive. All are above 1,000 yuan. Just now we also mentioned that the reverse osmosis water purifier has higher purification precision, but the ultrafiltration water purifier in the picture below shows that their products use ultrafiltration membranes to retain minerals beneficial to the human body. And trace elements, while RO reverse osmosis pure water machine has high filtration precision and cannot retain trace elements and minerals in water. Is this really the case?
In fact, this sentence is very vague. After reading the membrane classification, we know that the difference between ultrafiltration membrane and reverse osmosis membrane is mainly due to the membrane pore size. The reverse osmosis membrane does not retain the trace elements and minerals in the water, but because the minerals and trace elements themselves are good or bad, and the quality of these substances is not distinguished by the particle size, the ultrafiltration membrane cannot be judged. Which minerals and trace elements are beneficial to the human body. The logic of this sentence is that there are minerals and trace elements beneficial to the human body in the water → the reverse osmosis membrane cannot retain these substances, and the ultrafiltration membrane can retain these substances → the ultrafiltration water purifier is better. But the big premise of this logic ignores another aspect - there are also minerals and trace elements that are harmful to the human body. Therefore, ultrafiltration is better than reverse osmosis. Of course, they did not explicitly say this in propaganda, but it is logically guiding consumers to think in this direction.
Ultrafiltration membranes can effectively shield suspended particles, colloids, turbidity and bacteria, but the removal efficiency of organic matter in water is not high. So the fact is that both ultrafiltration and reverse osmosis have their own advantages, and each has its own shortcomings. Which one to buy depends on the specific needs and prices.
When it comes to minerals and trace elements, some water purification products on the market have added a mineralization function to supplement the filtered minerals in the water. That is to say, on the basis of purification, some mineral elements beneficial to the human body are added to the water by adding the slate, but the effect is still controversial in the academic world, and it is not necessarily useful.
Look at the water purifier of this faucet, using the analogy method to compare its purification accuracy to one thousandth of the diameter of the hair, and ask: "Do you feel relieved about such filtration accuracy?" In fact, this precision is ultrafiltration membrane. The precision of the ultrafiltration membrane is difficult to remove in the water and it is as difficult to remove. According to this statement, the filtration accuracy of the reverse osmosis membrane is one thousand times higher than that of this water purifier! Conversely, the purification accuracy of this water purifier is only one thousandth of that of the reverse osmosis water purifier. Are you still assured of the filtering accuracy? The facts are the same, but in other words, the effect is opposite. Therefore, when purchasing a water purifier, you will have to think a lot when you encounter a lot of rhetorical or figurative statements.
In addition to the filter element, filter membrane, and filtration accuracy, we will also see parameters such as “purified water flow rate†and “rated total water purification amountâ€. The meaning of “rated total water purification amount†is that without changing the filter element. The amount of water that can be purified from the time the consumer starts using it to when it is necessary to replace the filter element. However, due to the different water quality in different regions, this figure is only a reference; the greater the net water flow, the faster the water output.
Of course, in addition to what we just said, there are many other factors that will be included in the scope of our purchase of water purifiers, but know some common sense, at least we can make more judgments in the face of advertising. . Source: Pacific Internet Author: sea
Scan the QR code below, pay attention to the WeChat public number "Jiuzheng Cabinet network "; you can view the popular article " Buy a cabinet, 1550/m does not buy, 1500/m does not look back, 1450/m gimmick, the price is 1150/ How do you sell the cabinets of rice, let's go! 》 , want to communicate with peers can join the Jiuzheng building materials network cabinet exchange group]
Mosaic as a wall decoration product is widely in the interior wall and floor. It has Glass Mosaic,ceramci mosaic and Stone Mosaic. Normally the size is 300*300mm,305*305mm,also can customize the size.
Mosaic Tiles,Glass Mosaic Tiles,Mosaic Wall Decoration,Stone Mosaic Tiles
Foshan Castel IMP&EXP Co.,Ltd , https://www.foshancastel.com