Year Established: 2019 Start Date: 2019-05-31 End Date: 2020-05-30
Total Federal Funds: $20,000 Total Non-Federal Funds: $40,000
Principal Investigators: Siamak Nejati
Abstract: Providing ample potable water to match the growing demand for the safe drinking water has been challenged by the quality of our water resources. In Nebraska, farming practices pose more challenging problems to the sustainability of drinking water resources. As a result, implementing tertiary water treatment for removing the excess Nitrate content will be necessary. Currently the most economical way of treating Nitrate-N contaminated water is to use Reverse Osmosis (RO). The economy of RO systems and plants are well-established, and it is expected that the application of RO to grow rapidly. Nonetheless, both the point-of-use and plant scale RO systems suffer from one major drawback; the biofouling of the RO modules. Biofouling is a possible condition for any open systems and needs to be addressed at the source. In RO modules biofouling is taking place on the active surface of the state-of-the-art thin-film composite (TFC) membranes. The active surface of a TFC membrane is composed of Polyamide (PA) layer, which is composed of a thin polymeric filmâ€“thinner than 20 nanometers. Biofouling often deteriorates membrane performance by decreasing separation efficiency and product water yield and leads to prematurely discarded membrane modules. Excluding maintenance and labor, the financial burden of replacing modules, due to biofouling, is often beyond the resources of a small community. As RO becomes the dominant water purification method for inland communities, it is necessary to devise methods and materials that can enhance the longevity of membranes through inhibiting bacterial growth. Here we propose a method to develop sustainable approaches for rendering the RO membranes resistant to biofouling. We approach this goal using our knowledge of surface science, polymer chemistry, and biology and will design materials and organic coatingsâ€“with a molecular precisionâ€“to mitigate fouling more efficiently and fight bacterial growth. We will establish a process to rejuvenate the surface of TFC membranes and move toward permanent antibacterial RO membranes. Our approach is to defend the surface from fouling and terminate the attached bacterial through using biocides, chelated in a supramolecular coating. To do so, we will develop a mild chemical reaction pathway, in aqueous media, and impart desired functionality to the membranesâ€™ surfaces without compromising their performances. The functionalized surface will be tuned, with molecular precision, to further apply an antibacterial coating. The supramolecular coatings, which possess significant ion exchange (IEX) capacity, will be our Trojan horses loaded with the biocidal copper ions. These IEX layer can be regenerated and thus the surface can be maintained active for a longer period.