2017/06/17 by James W. Palko, Palko, James W., Diego I. Oyarzun +7
Chemical Engineering · #Ammonia Synthesis and Nitrogen Reduction
paper · pdf · doi:10.48550/arxiv.1706.05482
Nitrate is an important pollutant in drinking water worldwide, and a number\nof methods exist for the removal of nitrate from water including ion exchange\nand reverse osmosis. However, these approaches suffer from a variety of\ndisadvantages including requirements for supply and disposal of brine used for\nregeneration in ion exchange and low water recovery ratio for reverse osmosis.\nHere, we demonstrate the use of high surface area activated carbon electrodes\nfunctionalized with moieties having high affinity for adsorption of nitrate\nfrom aqueous solution, such as those used in ion exchange. Adsorption of\nsurfactant molecules having a quaternary amine ionic group to the activated\ncarbon surfaces provides functionalization of the surfaces without complex\nchemistries. The functionalized electrodes have adsorption capacities of about\n80 mg NaNO3 per gram of activated carbon material. Unlike a traditional ion\nexchanger, the functionalized surfaces can be repeatedly regenerated by the\napplication of an electrostatic potential which displaces the bound NO3-\nwhile leaving an excess of electronic charge on the electrode. The cell is\ncompleted by an inert counter electrode where Faradaic reactions occur during\nregeneration. Up to approximately 40% of the initial capacity of the electrode\nis accessible following electrical regeneration.\n