Forward Osmosis-Searching for New Technology of Water Treatment Desalination
Forward Osmosis, as a potential new technology of water purification and desalination, is undergoing theoretical research and practical exploration in the world from multiple perspectives and at a deep level. Forward osmosis and reverse osmosis are a pair of mutually reversible methods. Abroad, in 1976, there was the original attempt of liquid-liquid system, and domestically, in 1992, the positive osmosis (non-pressurized) adsorption osmosis desalination of liquid-solid system was invented (CN92110710.2). Until about 10 years later, and then re-follow the international trend, began to standardize the pattern of imitation reproduction, in 2008 there is a review report. With the rapid development of science and technology, pressure-driven reverse osmosis membrane separation technology (RO) in the membrane, membrane group device, equipment and process have been greater innovation and improvement, but people are also increasingly aware of RO technology in the field of energy saving, environmental protection limitations, and in terms of desalination, RO technology can be considered to be close to the peak of development. Therefore, foreign countries have carried out a "forward osmosis membrane separation technology (FO)" of the relevant research, and has achieved certain results in the field of desalination, sewage treatment, food processing, medicine and other fields have been applied, in particular, "pressure retarded osmosis (FRO) seawater generation In particular, "pressure retarded osmosis (FRO) seawater power generation" is a very promising technology for the development of clean renewable energy J. However, little attention has been paid to forward osmosis membrane separation technology in China, and there are not many related studies and papers. Although, in the 1990s, China had a creative invention "non-pressurized adsorption osmosis desalination" (CN92110710.2).
Forward osmosis separation technology has been applied for a long time. Long ago, people used salt for long-term food storage because most bacteria, molds, and pathogens die of dehydration or become temporarily inactive due to osmosis in a high-salt environment. Today, people have begun to use forward osmosis membrane separation technology for seawater desalination, industrial wastewater treatment, waste permeate treatment and other research; the food industry in the laboratory to use forward osmosis membrane separation to concentrate beverages; emergency rescue when the life-support system using forward osmosis membrane separation technology to produce fresh water. With the development of materials science, forward osmosis technology has been applied to the controlled release of drugs in the human body. (1990s)
Non-pressurized adsorption-permeation desalination, or "forward osmosis", allows water to pass through a porous membrane by forward osmosis into a super-absorbent adsorbent or salt concentration even more than seawater solutions or solids, without external pressurization, but the solution of the special salt extracts can easily evaporate without adding too much heat (heating can be used to make the water more concentrated). Need to add too much heat (heating energy and reverse osmosis pressurization energy ratio?) . Sub-solid salt, liquid salt direction. Solid salt desorption consumes less energy.
Desalination technology: non-pressurized adsorption osmosis seawater desalination method (CN92110710.2) 1992: Deng Yu's invention in the 1990s of the last century, "American Chemical Abstracts" included.
The other two methods are innovative and improved in the film structure: water softener principle and function: according to the principle of ion exchange, that is, Na + exchange Mg2 + Ca2 +, so that the hardness of the water is reduced to less than 70 mg / liter to become soft water, the main function of this water treatment equipment is to get rid of water alkali, scale.
Advantages and disadvantages of water softener water treatment equipment:
Advantages: remove scale, alkali effect is good, at the same time, the flow rate is large, basically does not reduce water pressure. After the water softener water treatment equipment produced by the water, cleaning ability is particularly strong, laundry, shower, beauty care effect; can also reduce energy consumption. At the same time also save washing supplies, reduce the intensity of household chores. Water softener water treatment equipment produced by the most suitable for domestic water.
Disadvantages: water softener water treatment equipment can not get rid of bacteria, viruses, organic matter, can not drink directly; regeneration requires salt consumption; and produce a certain amount of waste water.
Application of softened water:Bathroom, kitchen, laundry, heating, boiler, central air conditioning equipment water supply, beauty care and other vast areas. Water purifier principle and function: using PP cotton, activated carbon and RO membrane cartridge, five or more than five levels of filtration, the core of which is the RO membrane, RO membrane is currently the highest filtration accuracy of the cartridge. The water produced is pure water, and can be drunk directly.
Pure water machine water treatment equipment advantages and disadvantages:
Advantages: pure water machine water treatment equipment with high filtration precision, suitable for a variety of water quality, purified water is pure water, good taste, does not contain any impurities.
Disadvantages: water purifier water treatment equipment daily water production is small, can only solve the drinking and cooking; the first three filter cartridges short life, the need for regular replacement of the filter cartridge; is not suitable for a long period of time as drinking water, especially children and the elderly is more inappropriate for long-term drinking of purified water.
Ultra-filtration machine is a water purifier water treatment equipment in the mainstream products, with high precision, good purification effect, long filter life, and can automatically clean the filter.
Principle and function of the water purifier: 0.01 micron ultrafiltration membrane separation technology, can effectively get rid of water sediment, rust, suspended solids, colloids, bacteria, viruses, macromolecules, organic matter and other harmful substances.
Water purifier water treatment equipment advantages and disadvantages:
Advantages: water purifier water treatment equipment with high filtration accuracy; purified water close to mineral water, can be directly drinking; large flow; filter life; automatic cleaning of the filter cartridge; does not require electricity; no waste of water.
Disadvantages: water purifier water treatment equipment to get rid of scale, alkali effect is poor, applicable to the hardness of the region below the medium; a single ultrafiltration machine can not completely remove the odor in the water, the water taste is poor; change the core of the more troublesome, can not completely remove the heavy metals in the water. Nanofiltration membrane water treatment machine is a nanofiltration membrane as the main component, the structure is slightly loose, similar to the reverse osmosis membrane water treatment machine, nanofiltration membrane is a charged membrane, can be electrically adsorptive, on the electrically high F ions, etc., can be partially removed, and has a nano-micron level pore size, macromolecules can not be through the water molecules in the free state partially through the NaCl partially through the calcium ions, magnesium ion, a smaller portion of the can be passed. Includes the advantages of the above water treatment machine, and avoid the two water treatment.