Bipolar Electrochemical Uranium Extraction from Seawater with Ultra-low Cell Voltage

The efficient extraction of abundant uranium resources from seawater can provide important raw materials for the sustainable development of green nuclear energy. The electrochemical extraction with fast kinetics and adjustable selectivity is a very promising method, which overcomes the capacity limitations of traditional physicochemical adsorption. However, conventional electrochemical systems face challenges such as high energy consumption, low extraction efficiency, and poor selectivity. Herein, we have proposed a bipolar electrochemical uranium extraction (EUE) system with ultra-low voltage. The working principle of this bipolar EUE system are based on anodic electrochemistry-assisted indirect uranium reduction coupled with cathodic direct electro-reduction of uranium species. Such a bipolar EUE device exhibits most promising EUE voltage. At an ultra-low voltage (0.6 V), the bipolar EUE efficiency is ~100% within mere 4 h encompassing a wide range of uranium concentrations (1-100 ppm). This bipolar EUE system in natural seawater displays excellent U selectivity, extraction percentage (above 85.3%), long-term stability (45 cycles) and the low energy consumption (1944 kWh kg-1 U) and economic cost (83.2 USD kg-1 U). This design and research concept of the bipolar EUE system also provides a reference for sustainable recycling of other waste resources.