Reverse osmosis (RO) membranes are used in the field of desalination technology. Nowadays, more than 16 million m3/day of water is treated by this means. RO membranes can be classified by the type of membrane material as cellulose acetate, thin-film composite and ceramic membranes. Thin-film composites (TFC) are the most widely used membranes in the global market.
Recent developments focus on additives for the active layer of TFC desalination membranes, which change the chemistry and structure of the interfacially polymerized film, in order to increase hydrophilicity and water flux, improve adsorption and diffusion of reactants, or impart antifouling properties.
The aim of this technology is the use of zwitterionic moieties as co-reactants or coatings for the active layer of TFC desalination membranes in order to increase their performance. Zwitterionic trialkoxysilane sulfobetaine monomers (SPPT) were used in the interfacial polymerization process for the preparation of thin film composite (TFC) membranes for reverse osmosis (RO) applications.
Zwitterionic structures have attracted a great deal of interest in water treatment membrane preparation because of their high degree of hydrophilicity and antifouling properties. The zwitterionic nature of specially designed and properly incorporated compounds in this technology provides increased membrane hydrophilicity and electrostatic repulsion between the membrane surface and charged contaminants in the feed solution. The combination of these two properties results in a positive effect on membrane flux and salt rejection and also eventually decreases membrane fouling and membrane defects arising from chemical cleaning.
Technology Features, Specifications and Advantages
Significant improvements up to 30% in the water flux without loss of salt rejection at seawater desalination conditions were observed in the modified membranes with low SPPT concentrations. Our invention aims to desalinate high salinity seawater at higher recovery rates than the state of the art membranes. These are the most promising features of this invention:
- Higher water flux without loss of the salt rejection
- Decreasing membrane fouling and membrane defects
High-performance desalination membranes can be utilized in several areas such as;
- Desalination and wastewater treatment industry
- Chemical industry
- Pharmaceutical industry
- Food industry for the processing of liquid items
Improvements of TFC membranes in general and especially for seawater desalination purposes have many contributions to economy, wealth and scientific knowledge. As part of the water management strategy, global companies are increasingly employing membrane technologies to improve output efficiency.
- Longer membrane lifetime with a higher salt rejection after repeated cleaning
- Significant improvements in the performance of TFC membranes will increase the feasibility of desalination technology for drinking water production