Membraneless Water Desalination System

Access to freshwater is an increasingly important national and international issue. Today, about three billion people around the world have no access to clean drinking water. To address the challenge of providing clean fresh water to meet the earths growing population, new innovative solutions are required to desalinate water without using membranes. A new membraneless desalination system was developed based on capacitive deionization technology. A desalination reactor was designed that incorporated inexpensive carbon-based electrodes that were enhanced to give high capacitance. These material and reactor design enhancements were operated in the desalination mode as well as in the regeneration mode to recover some of the energy. A Phase I program demonstrated a new capacitive deionization cell design that can process high flow rates of brackish to seawater sources. Inexpensive carbon based electrodes were functionalized using low cost materials and methods to enhance the capacitance. Cells were developed and shown to desalinate water showing the merits of the electrode materials and reactor design. A mathematical model of the capacitance deionization cell was developed to help elucidate the desalination and regeneration operating modes. A Phase II program is focusing on optimizing the electrode capacitance, optimizing a mathematical model of the capacitive deionization reactor, scaling the cells to larger sizes, developing, and optimizing the cell manufacturing process, and producing a 400 gallon/day operational system that will process seawater to 500 ppm salinity levels. This membraneless desalination system simplifies the operation and maintenance of the reactor by eliminating membrane fouling while helping to lower the operating costs for desalinating water. The initial market for this reactor is as an onsite water deionization system that can provide potable drinking water from ocean and brackish waters.