Osmotic processes are based on the natural ability of a solvent to pass from a concentrated medium, leaving foreign mineral particles. The delay of the latter is facilitated by semipermeable membranes and pressure, under the force of which diffusion (flow) occurs. In the usual sense, osmosis is a filtration that purifies water. For a visual representation of this process, you can turn to the technology of desalination and sterilization of water.
Obtaining a pure liquid occurs as a result of its natural passage through special barriers, behind which undesirable trace elements remain. On marine vessels, reverse osmosis can save water from salt. In industry and medicine, as a rule, careful treatment of aqueous media is required to obtain certain formulations.
Reverse osmosis
From the point of view of the cleansing function, it is advisable to use just reverse osmosis. Scientists have long discovered the ability of multicellular organisms to pass or retain water. Each cell has membranes protruding filters that allow passage of water, but leave solid and semi-dissolved elements. During these processes, a metabolism is carried out - the beneficial ones remain in the body, and toxins with slags - on the contrary, are excreted. It is worth noting that osmosis is a natural procedure, but pressure is often applied to achieve better cleaning results.
So, in the case of water, a semipermeable membrane will ensure the passage of H2O and the delay of elements dissolved in it only until equilibrium with the concentrated medium occurs. It is important to note here that osmosis is also direct diffusion, which can be discussed when the force of natural pressure begins to exceed hydraulic.
Reverse osmosis membranes
Synthetic polymers are used in the manufacture of osmosis membranes . The main objective of such elements is to create a barrier to high molecular weight pollutants, while ensuring the passage of low molecular weight substances, including oxygen, carbon dioxide and chlorine.
Water reverse osmosis systems built on polymer membranes contribute to the separation of pure liquid from impurities. Unlike other methods of modern filtration, osmosis involves the presence of water on both sides of the filtration component. However, on the one hand there is permeate (pure water), and on the other, there is a liquid with impurities, including salts, colloids, microorganisms, and various organics.
Osmosis membrane productivity
The artificial reverse osmosis process in its efficiency is able to process an average of 20% of the total volume of water. However, some high-tech installations bring this figure to 80%. Another thing is that for the most part they are highly specialized osmotic filters, inaccessible to the mass consumer. Nevertheless, the reverse osmosis system is currently considered one of the most high-quality and promising technologies to purify water of any quality.
Prefilters
As a rule, reverse osmosis systems involve several stages of filtration. The prefilter becomes the initial barrier to contaminants and impurities in water. Its task is not so much in preparing water for domestic needs as its primary purification from elements that can damage the membranes of the main filter. In particular, at this stage, the reverse osmosis system traps chlorine and other impurities that are undesirable for contact with the post-filter.
As a rule, carbon filters are used for initial cleaning - they are usually used in cartridge models. Coal "drainage" eliminates the liquid from chlorine, which is harmful to the polymer membrane. That is, it is important to understand the importance of preparing the fluid, which will further be processed by osmosis. Water purification - what is it from the point of view of safety of filtration equipment? First of all, protection from chemical processes that destroy the structure of cleaning elements. The elimination of the same chlorine at the preliminary stage will significantly increase the durability of the system.
Postfiltration Membranes
There are two types of membranes for basic filtration - flat and tubular. Flat models are film products having reinforcement or a base in the form of a substrate. For reverse osmosis osmosis, multilayer versions are usually used, where each film is designed for specific loads. The base layer of the membrane usually performs a strengthening or supporting task, the second one is directly involved in the filtration, and the final one provides external protection.
Tubular models - water filters, the osmosis of which is provided by special fibers, has a diameter of up to 0.5 mm. The hollow structure of the fibers is considered the most effective in cleaning. Due to the small size of the membrane fibers, a significant working surface is provided. But the principle of careful filtration naturally leads to a significant drawback - tubular membranes are quickly contaminated, requiring high-quality water treatment.
Installation and principle of operation of filters
To ensure long-term and effective cleaning, an appropriate installation of equipment is required, which involves drawing up a connection diagram for the filter and pump. As a rule, the installation of reverse osmosis also involves the introduction of booster pumps, due to which artificial pressure is created. There are high and low pressure sensors.
Water enters the reverse osmosis unit directly from the water supply, after which the treatment in prefilters with coal passes. The pump is installed immediately after the pre-treatment filter, but up to the diaphragm. After initial cleaning, water enters the inlet of the pump unit. The output of this device is connected to a shut-off valve. On the other side of the valve, it is necessary to connect a tube passing to the tap with clean water and the membrane.
Manufacturers and prices
Both domestic filter manufacturers and foreign firms offer osmosis at home, having the opportunity to use high-quality and clean water. In particular, AquaFor and Geyser companies will allow the installation of reverse osmosis, the price of which varies from 8 to 14 thousand rubles. The difference of several thousand is due to the performance and functionality of the filters. For example, the Prestige MP model is the top model in the Geyser line and allows water mineralization. Atoll company is betting on improving the basic parameters of its models, offering the Patriot modification with a 5-step cleaning and a 12-liter tank for 8.5 thousand.
Decent options in the domestic market of membrane filters are also offered by Japanese developers. For example, Expert Osmos company in the budget line provides a functional reverse osmosis, the price of which is 9 thousand. Paying another 6 thousand, you can provide the house with a Praktic Osmos filtration system, which is also equipped with a pump, electronic control and automatic washing of the membrane.
Pros and cons of reverse osmosis
There are no equal filters for reverse osmosis in the quality of the main task. For example, alternative jug installations even in the best modifications are not comparable in depth of cleaning. But it is precisely this factor that raises doubts about the usefulness of membrane devices, since osmosis is the process by which water becomes completely distilled. True, many modern models allow you to control cleaning, while maintaining the mineralization of the liquid.
Among the disadvantages of reverse osmosis and the need to use complex equipment. Several filters, a tank and a branching system exclude the possibility of compact installation of such systems. One way or another, reverse osmosis filtration, subject to development towards increased ergonomics, may well become the undisputed leader in the category of means of providing clean and healthy water.