NH3 Separation Membrane for CO2 Utilization

There are abundant, valuable mineral resources available in seawater, brines, and bitterns. These mineral resources are generally not being exploited because the separation of these minerals from salt mixtures is challenging and cost prohibitive. New methods for separating minerals from salt waters have been recently demonstrated to be versatile and effective. The critical, limiting problem with ammonia-based separation methods is that the ammonia needs to be recovered and recycled. Recycling the ammonia is needed to minimize energy costs and avoid the intensive carbon dioxide emissions associated with original ammonia production. Efficient ammonia recovery will instead enable the consumption of carbon dioxide by producing salable carbonate minerals while processing the salt waters. Instead of mining sodium carbonate, magnesium carbonate, and calcium carbonate from the ground, these minerals should be produced by treating salt waste waters and profitably consuming millions of tons of carbon dioxide per year. A separation membrane technology will be developed for recovering the ammonia. The Department of Energy is supporting the development of membranes for industrial applications because passive membrane separation is an energy efficient separation method. The proposed separation membrane technology will selectively extract ammonia using the acid/base properties of ammonia. Luna will demonstrate the complete process for recovering ammonia using the separation membrane. The ammonia recovery process will be demonstrated on the benchtop scale in conditions relevant to practical application. The application of ammonia to actually separate minerals from salt waters is outside the scope of this project and is expected to be applied by the end-user of the proposed ammonia recovery technology. Commercial Applications and Broader Benefits The technology will facilitate the production of several marketable minerals by enabling better processing methods in the salt industry. These minerals are consumed on the order of millions of tons per year in the US. The US salt industry produces 60 million tons of salt per year and is large enough to sustain the production of most of these additional minerals. Producing these minerals with less expense and energy costs will benefit agricultural, metal, chemical, and energy industries. Many salt production facilities in the US are be large enough to consume all of the carbon dioxide produced by a typical fossil fuel power plant for producing carbonate minerals. Lowering anthropogenic carbon dioxide emissions by enabling profitable carbon capture and utilization is also a benefit to society.