The Role of Water Treatment Chemicals in Membrane Separation Technology

Membrane separation technology has become an important part of advanced water treatment due to its high separation efficiency, low energy consumption, and environmental friendliness. It is widely used in drinking water purification, industrial wastewater treatment, and seawater desalination. However, membrane fouling, membrane degradation, and low separation efficiency are key problems that restrict the development and application of membrane separation technology. Water treatment chemicals play a vital role in solving these problems, improving membrane performance, and extending membrane service life. This article explores the application of water treatment chemicals in membrane separation technology and their working mechanisms.

Membrane fouling is the main factor affecting the performance of membrane separation systems, which is caused by the adsorption and deposition of pollutants (such as colloids, microorganisms, and organic matter) on the membrane surface or in the membrane pores. To prevent and control membrane fouling, various water treatment chemicals are used, including membrane cleaners, antifouling agents, and pretreatments chemicals. Pretreatment chemicals, such as coagulants and flocculants, are used to remove suspended solids and colloidal substances in raw water, reducing the load of membrane fouling. Antifouling agents, such as quaternary ammonium salts, polyacrylic acid derivatives, and zwitterionic polymers, can form a protective layer on the membrane surface, inhibiting the adsorption of pollutants and reducing membrane fouling.

Membrane cleaners are used to remove existing fouling on the membrane, restoring membrane performance. They are divided into physical cleaners and chemical cleaners. Chemical cleaners, such as acids, bases, oxidants, and enzymes, are more effective in removing stubborn fouling. For example, citric acid and hydrochloric acid are used to remove inorganic scale fouling; sodium hydroxide and sodium hypochlorite are used to remove organic fouling and microbial fouling; enzyme cleaners (such as protease and lipase) are used to degrade protein and oil pollutants. In addition, membrane preservatives are used to prevent membrane degradation during storage and operation, ensuring the stability of membrane performance. The selection of water treatment chemicals for membrane separation technology should be based on membrane material, water quality, and operating conditions to avoid damaging the membrane and ensure the efficient operation of the system.