Water purifier principle, filter membrane, filter media details

Water purification industry brands, water treatment is complex, there is a single treatment method, there are a variety of filter membranes, filter media composite treatment. But from a technical point of view, all changes do not depart from the same, today Susan will take you to understand what this “Zong” is all about, so that you have a variety of water purification technology, configuration, advantages and disadvantages at a glance.

1. Domestic, commercial water purifier principle According to the accuracy of the filter membrane pore size and the ability to remove dissolved ions classification, water purification membrane including microfiltration, ultrafiltration, nanofiltration, reverse osmosis four categories. The main means of filtration of drinking water is only ultrafiltration, nanofiltration, reverse osmosis three categories.

1.1 Ultrafiltration membrane (UF)
Hollow fiber ultrafiltration membrane filament: 0.5-2.0mm, inner diameter of 0.3-1.4mm, hollow fiber tube wall covered with microporous filtration precision of 0.5-0.01 microns, pore size in order to be able to intercept the molecular weight of the substance up to a few thousand to several hundred thousand. Raw water flows under pressure on the outside or inside of the membrane, constituting external and internal pressure respectively. Ultrafiltration is a dynamic filtration process, the retained substances can be excluded with the concentration of small, without blocking the surface of the membrane, can be long-term continuous operation. Ultrafiltration membrane is one of the earliest developed polymer separation membranes, capable of removing bacteria, colloids, organic matter and other impurities larger than 0.01 micron.

1.2 Nanofiltration Membrane (NF)
Nanofiltration (Nanofiltration) is a membrane separation technology between ultrafiltration and reverse osmosis, with a molecular weight cutoff in the range of 80-1000 and a pore size of 1 nanometer, hence the name nanofiltration. Nanofiltration technology is a membrane separation technology separated from RO technology, which is the continuation and development branch of ultra-low pressure RO technology. In the past a long time, nanofiltration membrane is known as ultra-low pressure reverse osmosis membrane (LPRO: Low Pressure ReverseOsmosis), now, nanofiltration technology has been separated from reverse osmosis technology, and become between ultrafiltration and reverse osmosis technology, an independent separation technology, has been widely used in the preparation of potable water, pharmaceutical water preparation, food industry, It has been widely used in drinking water preparation, pharmaceutical water preparation, food industry, environmental protection and many other fields, becoming an important branch of membrane separation technology. Principle: Nanofiltration membrane, like ultrafiltration and reverse osmosis membrane separation process, is also a membrane separation process driven by pressure difference, which is an irreversible process. The separation mechanism can be described by using the charge model (space charge model and fixed charge model), fine pore model, and electrostatic rejection and three-dimensional obstruction model proposed only in recent years.

Advantages: Compared with other membrane separation processes, one of the advantages of nanofiltration is that it can retain small molecular weight organics and high valence ions through ultrafiltration membranes, and dialyze some of the inorganic salts and minerals retained by reverse osmosis membranes - that is, it can make “concentration” and desalting Synchronization. Can maximize the removal of all pollutants in the water and can retain the appropriate amount of human mineral needs.

1.3 Reverse osmosis membrane (RO)
RO is the abbreviation of English Reverse Osmosis Membrane, the Chinese meaning is: reverse osmosis / reverse osmosis, the general flow of water from low concentration to high concentration, water once pressurized, will flow from high concentration to low concentration, also known as reverse osmosis principle. As the pore size of RO membrane is five millionths of a hairline (0.0001 micron), which is generally invisible to the naked eye, bacteria, viruses are 5000 times, therefore, only water molecules can pass through, and any other impurities, ions, and heavy metals will be discharged from the waste water pipe, and the produced water will be pure water. All the desalination process, as well as astronauts waste water recycling treatment are used in this way, so the RO membrane is also known as in vitro high-tech “artificial kidney”. At present at home and abroad, medical military civil field, all take the top RO membrane for polymer filtration. China Yikang has also authoritatively released, in 2013, reverse osmosis water purification equipment year-on-year growth rate of up to 77.6%. In the future, reverse osmosis membrane processing technology will become the most mainstream product technology.

2. Water purifier auxiliary filter media
The main means of purification of water treatment is membrane filtration technology, but the auxiliary filter media is also very critical, its role is to be able to low-cost directional removal of some of the impurities in the water, but also on the main high-precision filter membrane to play a protective role. Auxiliary filter media, including but not limited to: activated carbon, KDF, resin, PP cotton, metal filters, quartz sand, etc. as an auxiliary means of water purification to achieve the purpose of comprehensive treatment.

2.1 PP cotton
PP cotton filter made of polypropylene (PP) hot melt, the precision of 1um to 5um. is a high-efficiency, low-pressure differential, long service life and applicability of a wide range of filter elements. Main function: to intercept and screen out physical pollutants larger than the diameter of the filter hole through the logistics. Remove particulate impurities in water larger than 5 microns, such as: suspended solids, sediment, red worms, rust, colloids and other bulk substances, reduce the turbidity of water. Scope of use: Widely used in pure water, food and drinking water pre-filtration treatment; with RO reverse osmosis membrane, nanofiltration membrane, ultrafiltration membrane, etc. as pre-filtration pretreatment. Replacement cycle: the treatment of water is generally 5 tons, the replacement cycle of 3-6 months is appropriate, depending on the quality of the source water and water consumption.

2.2 Activated carbon
Manufacturing process: Activated carbon for water treatment is generally made of high-quality coconut shells, refined through a series of production processes, with a black appearance. The advantages are developed pore structure, large specific surface area, strong adsorption performance, 1 gram of coconut shell activated carbon filtration pore expansion area of about 2000 square meters. Small reservoir resistance, stable chemical properties, easy to regenerate. According to the need to make into powder, granular, sintered rod or fiber. Different water treatment occasions apply to different activated carbon properties Main function: through super adsorption capacity to remove residual chlorine, color, odor, heavy metals and other toxic and harmful substances, and can improve the taste of water. Scope of use: widely used in the treatment of pure water, food and drinking water; with nanofiltration membrane, RO reverse osmosis membrane, ultrafiltration membrane, etc. as a pre-filtration pretreatment.

2.3 Copper-zinc alloy (KDF)
KDF is a high-purity copper-zinc alloy, with a long service life, can be repeated recycling characteristics.KDF water treatment principle is the use of redox reaction, KDF and oxidizing harmful substances in the water for electron exchange, many harmful substances into harmless substances. Heavy metal ions and zinc ions replacement to achieve the purpose of removing heavy metal ions.

2.4 Softening resin
Introduction: Softening, i.e. reducing the hardness of water. The water softening system includes three parts, i.e. ion exchange part, salt regeneration part and control part. Ion exchange technology is the working principle of the softening system, the main body of which is the ion exchange resin, due to the hardness of the water is mainly formed by calcium, magnesium and expressed, so generally use cation exchange resin, the water in the Ca2+, Mg2+ (the main component of scale formation) replacement, with the increase of Ca2+, Mg2+ within the resin, the resin removes the effectiveness of the Ca2+, Mg2+ is gradually reduced. Therefore, when the water softening equipment is used for a period of time, it is necessary to regenerate the resin with 25% NaCl regeneration part to restore the efficiency of the resin and improve the service life of the resin. The control part can realize the automatic operation of the whole system, and salt regeneration can be carried out automatically according to the running time of the system or through the amount of water.

2.5 Silicon phosphate crystal
Silicon phosphate crystals from soda, phosphoric acid, calcium carbonate and other active ingredients in the 1200-1700 ℃ high-temperature technology fired from the glassy ball. Water system corrosion, scale inhibition, extend the service life of the equipment has played a positive role.

2.6 Water softener (high-purity sodium chloride)
Water softening salt, also known as ion exchange resin regeneration agent. Its main chemical composition is sodium chloride (NaCl), the content of 99.5% or more, generally shaped as a ball agent. When the impurities adsorbed by the resin of the water softening equipment are more and more, its adsorption capacity will be gradually reduced, and to remove the impurities adsorbed by the resin (mainly calcium Ca, magnesium Mg ions), it is necessary to use sodium ions (Na), through the method of backwashing, through the exchange of ions and impurities adsorbed by the resin ions (mainly calcium Ca, magnesium Mg ions), to replace out, so as to restore the resin's adsorption capacity, the process is also called ion exchange resin regeneration. This process is also called ion exchange resin regeneration.

2.7 Other auxiliary filter materials
Including metal filters, quartz sand, mineralized balls, mafic stone, etc..