The 13 factors that affect the desalination rate of reverse osmosis are the percentage of soluble impurities removed from the inlet water of the equipment through the reverse osmosis membrane. Desalination rate=(1- salt content in produced water/salt content in influent) × 100%. The desalination rate of reverse osmosis membrane elements is determined during their manufacturing process, and the high or low desalination rate depends on the density of the ultra-thin desalination layer on the surface of the reverse osmosis membrane element. The denser the desalination layer, the higher its desalination rate and the lower its water production. The removal rate of different substances by reverse osmosis is mainly determined by the structure and molecular weight of the substances. Imported reverse osmosis membrane elements can achieve a removal rate of over 99% for high valence and complex monovalent ions, while the removal rate for monovalent ions such as sodium ions, potassium ions, and chloride ions is slightly lower but still exceeds 98%; The removal rate of organic compounds with a molecular weight greater than 100 can also reach 98%.
The factors that affect the desalination rate of reverse osmosis include: ◆ The desalination rate of ion valence increases with the increase of ion valence, and the desalination rate of divalent and trivalent salts is also higher than that of monovalent salts ◆ The desalination rate of molecular size increases with the increase of molecular diameter ◆ When the raw water temperature increases, the desalination rate increases due to the decrease of water viscosity ◆ When the raw water concentration increases, the desalination rate decreases ◆ When the working pressure increases, the desalination rate increases slightly but not significantly ◆ Although the membrane is not easily blocked under acidic pH conditions, the desalination rate decreases ◆ Dissolved gases are easy to permeate in a free state without removing CO2 SO2, O2, Cl2, H2S, etc; Hydrogen bonding tends to occur in compounds containing strong hydrogen bonds, with low removal rates, such as water, phenol, and ammonia; (This is precisely why the removal of impurities and dissolved substances in water is achieved to separate it from other substances. ◆ Organic matter in water has a polluting effect on the membrane, and the more organic matter there is, the more likely the membrane performance is to deteriorate. ◆ The hardness of water is higher, and the membrane is more prone to clogging. For high hardness water, softening treatment should be carried out first to reduce hardness before entering reverse osmosis. ◆ Solid particles and solid particles pose great harm to reverse osmosis membranes and must be pretreated. ◆ Microorganisms and bacteria in microbial water are harmful to the membrane and must be pretreated (our company uses ultrafiltration membranes for treatment, which is at an advanced level in China). ◆ Metal oxides cannot be removed by themselves when entering reverse osmosis, and should be regularly removed by chemical drugs.
