According to the industry, when the raw water passes through the reverse osmosis membrane, the insoluble salts will stay on the surface of the membrane and precipitate as a solid. Specifically, during the operation of the reverse osmosis equipment, the pressure generated during the low pressure washing process will produce fresh water, and the concentration of the water on both sides will naturally deepen, and the deepening will cause the concentration of the salt to deepen, in the salt. Contains a large amount of precipitable material, which will cause scaling after a long time.
Therefore, as long as the poorly soluble salts do not exceed the saturation limit, the occurrence of fouling can be effectively prevented. Among them, in terms of design, in order to better replace the concentrated water, it is possible to ensure that the salt content of the concentrated water is low.
The main insoluble salts in natural water sources are: Calcium Carbonate, barium sulfate, calcium sulfate, calcium fluoride, barium sulfate and silica. Experts caution that in the design of reverse osmosis systems, special attention should be paid to barium sulphate and barium sulphate. An increase in the concentration of calcium sulfate and a decrease in the temperature of the water also cause a decrease in the solubility of barium sulfate.
In addition, some inorganic substances with low content in natural waters are brought into the feed water by human factors, such as dosing. For example, inorganic salts such as phosphate, iron and aluminum tend to have low solubility products and are highly prone to occur. Fouling, so when the system is dosed with chemicals (such as flocculants, coagulants, scale inhibitors, acids and bases, etc.), the effects of these artificially introduced ionic components must be considered.
It is understood that sometimes there are cases where different agents that are added to each other cause the precipitation of insoluble substances, which in turn contaminate the membrane elements. The industry recommends that if you encounter this kind of situation, you should pay attention to the ingredients of these medicines when you add a variety of medicines, and conditionally, you can confirm their compatibility through experiments.
In general, in order to better protect the reverse osmosis equipment and prolong the service life of the reverse osmosis equipment, the raw water can be pretreated in advance, and the large particle impurities can be filtered by activated carbon or quartz sand filtration, and then softened by the ion exchange resin. Descaling can be avoided by removing calcium and magnesium ions from the water.
At the same time, the technical staff in the industry also said that in order to prevent fouling, the filter speed of the filter should not be too fast or too slow in terms of filtration speed. The backwashing process must have a certain time and flow rate, and the backwashing effect is good. The operation of the filter can be good; when the water flow is running, the uniformity of the water flow should be ensured, only the water flow is uniform, and the filtration effect can be good; in the filter material, the particle size and uniformity of the filter material need to be considered. In short, the rational use of membrane treatment of reverse osmosis equipment can further effectively prevent the occurrence of fouling in reverse osmosis equipment.
Chlorinated polyethylene is a saturated polymer material with a white powder appearance. It is non-toxic and tasteless. It has excellent weather resistance, ozone resistance, chemical resistance and aging resistance. It has good oil resistance, flame retardancy and coloring properties. It is an excellent impact modifier for PVC plastics and a synthetic rubber with good comprehensive performance. It has a very wide range of applications and has been widely used in cables, wires, hoses, tapes, rubber and plastic products, sealing materials, flame retardant transport belt , Waterproof coiled material, film and various profiles and other products.
As a PVC impact modifier, CPE135A has many advantages such as low price, excellent performance, and excellent aging resistance, but it has certain disadvantages in the use of high impact and high hardness products and low temperature resistant products CPE135A. For example, in the formulation of rigid PVC, a large amount of CPE will reduce the hardness and rigidity, which reduces the physical properties of the product; in addition, when the low temperature resistance requirement of PVC products exceeds minus 30°C, CPE135A cannot meet the requirements. Under normal circumstances, modified CPE, such as ACM, RGC135A, etc., can be selected for rigidity and hardness improvement; for low-temperature resistance modification, impact-resistant ACR or other impact modifiers with lower glass transition temperature can be selected.
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