Novel Electrochemical Process for Treatment of Perchlorate in Waste Water

摘要

The presence of toxic perchlorate in the environment is a growing public health and environmental health concern. Military munitions and the chemical and nuclear industries are major sources contributing to the presence of perchlorate in the natural environment. Perchlorate is very stable in the environment and difficult to remove with conventional techniques. Novel technologies are needed for for removing perchlorate in the environment in a simple, fast, cost-effective, and environmentally friendly manner. At the Pacific Northwest National laboratory, we developed an electrically switched ion exchange (ESIX) system based on a conducting polymer/carbon nanotube nanocomposite for removing perchlorate from drinking water and wastewater. The ESIX technology combines ion exchange and electrochemistry to provide a selective and reversible method for removing target species from wastewater. In this technique, an electroactive ion exchange layer is deposited on a conducting substrate, and ion uptake and elution are controlled directly by modulating the potential of the layer, resulting in a highly efficient use of electrical energy. The elution solution can be used repeatedly, minimizing secondary wastes and reducing costs normally required for standard ion exchange waste treatment. This project has used conductive nanocarbon materials as the support for electrochemically fabricating a conducting polymer nanostructure and for improving the stability and electrochemical properties of an electroactive ion exchanger. The electroactive ion exchanger nanocomposite has been incorporated into a flow reactor to selectively remove the perchlorates in wastewater. The results indicate that the ESIX technology is effective and selective for perchlorate removal and can potentially be used for large-scale treatment of wastewater.