Antifouling performance of spiral wound type module made of carbon nanotubes/polyamide composite RO membrane for seawater desalination

Robust nanocomposite reverse osmosis (RO) module was assembled using crosslinked polyamide (PA) and carbon nanotubes (CNT) membranes, and their fouling resistance in real seawater desalination conditions was evaluated. The CNT-PA nanocomposite membrane was used to build a 2 in. and 4 in. RO module. The modules were tested for fouling in the laboratory using bovine serum albumin (BSA) dissolved in simulated seawater. The synthesis of the crosslinked CNT polyamide structure resulted in a lower foulant interaction and high salt rejection rates (99.87 wt%). The RO-laboratory scaled modules showed excellent antifouling behavior compared with commercial antifouling membranes, maintaining a continuous operation without substantial pressure drop variations. Pilot-plant tests with real seawater were performed at the water plaza facility, Kitakyushu city, Japan. A RO industrial vessel built with CNT-PA nanocomposite modules showed superior antifouling performance with a stable operation for more than 100 days due to changes in surface charge and superficial fouling blocking. In contrast, antifouling commercial vessel showed 2.3 times higher foulant deposition. These CNT-PA nano composites RO antifouling modules for uninterrupted operation performance are ideal for desalination plants because they require less operation maintenance than commercial membranes, promoting green desalination technology, which is becoming increasingly important due to current environmental concerns.

Automated summary

The robust nanocomposite reverse osmosis (RO) module, assembled using crosslinked polyamide (PA) and carbon nanotubes (CNT) membranes, showed high salt rejection rates and excellent antifouling behavior in laboratory tests using bovine serum albumin in simulated seawater. The industrial vessel built with CNT-PA nanocomposite modules demonstrated superior antifouling performance and stable operation for over 100 days in pilot-plant tests with real seawater, compared to a commercial antifouling vessel. These CNT-PA nanocomposite RO antifouling modules are ideal for desalination plants, requiring less maintenance and promoting green desalination technology.