(538c) Polyamide Thin Film Nanocomposite (TFN) Membranes for Simultaneous Boron Removal and Desalination of Seawater

Production of potable water has become a worldwide concern. For many countries the available water resources are not adequate due to population growth and industrialization. Desalination of brackish or seawater has emerged as a solution to the limited water supplies. Reverse osmosis (RO) today is the leading technology that is responsible for producing more than half of the worldâ??s desalination capacity. Polymeric membranes have dominated the RO market since they offer high salt rejection, durability, small footprint and simple operation. An emerging problem is removing boron from seawater in order to meet the World Health Organization (WHO) recommendation of 2.4 ppm for potable water and 0.5 ppm for water used for irrigating crops such as citrus fruits and nuts. Since boron is present in seawater as boric acid whose effective diameter is nearly the same as that of a hydrogen-bonded cluster of water molecules, conventional RO membranes cannot effective achieve the WHO recommendations for boron removal. Recently, a new concept of mixed-matrix composite RO membranes was advanced whereby nanoparticles are embedded into the selective layer of thin film composite polyamide RO membranes fabricated on porous supports via interfacial polymerization. These mixed-matrix RO membranes offer considerably promise for r achieving desalination while concurrently reducing the boron concentration to the WHO recommendations. Incorporating materials such as zeolites and functionalized carbon nanotubes into the selective thin layer of polyamide RO membranes offer the potential for improving the boron rejection as well as the, flux and anti-fouling properties. However, this requires optimizing the conditions for loading, size, type, and functional groups of the nanomaterials as well as the interfacial polymerization and post-treatment protocols. This study reports the first assessment of the performance of thin film nanocomposite (TFNC) desalination membranes for more effectively removing boron from seawater.