What Factors Affect the Normal Operation of the Desalination Rate of a Reverse Osmosis Pure Water System?

Most ultrapure water systems and laboratory pure water systems are equipped with reverse osmosis systems. Reverse osmosis is a crucial component of pure water equipment, removing impurities such as inorganic salts, heavy metal ions, and organic matter from raw water. Many customers have requirements for the desalination rate when using ultrapure water, as this is an indicator of water quality. So, what factors affect the normal operation of the desalination rate of a reverse osmosis pure water system?

1. Ion valence: Desalination rate increases with increasing ion valence; divalent and trivalent salts have higher desalination rates than monovalent salts.

2. Molecular size: Desalination rate increases with increasing molecular diameter.

3. Raw water temperature: As raw water temperature increases, the desalination rate increases due to decreased water viscosity.

4. Raw water concentration: As raw water concentration increases, the desalination rate decreases.

5. Operating pressure: Increasing operating pressure slightly increases the desalination rate.

6. pH value: Although the membrane is less prone to clogging under acidic conditions, the desalination rate decreases.

7. Dissolved gases: Soluble gases in their free state easily permeate without removing CO2, SO2, O2, Cl2, H2S, etc.

8. Hydrogen bonding tendency: For compounds containing strong hydrogen bonds, the removal rate is very low, such as water, phenols, and ammonia. (This is precisely why impurities and dissolved substances in water are removed, achieving the separation of water from other substances.)

9. Organic matter: Organic matter in water fouls the membrane; the more organic matter, the more easily the membrane's performance deteriorates.

10. Water hardness: Higher water hardness makes the membrane more prone to clogging. High-hardness water should be softened before reverse osmosis.

11. Solid particles: Solid particles are extremely harmful to reverse osmosis membranes and must be pretreated.

12. Microorganisms: Microorganisms and bacteria in water are harmful to the membrane and must be pretreated.

13. Oxides: Metal oxides entering the reverse osmosis system cannot be removed automatically and should be removed periodically using chemical agents.