Efficient uranium electrochemical deposition with a functional phytic Acid-Doped Polyaniline/Graphite sheet electrode by Adsorption-electrodeposition strategy

The extraction of uranium is critical because it is an essential radioactive element for sustainable fuel supply. Herein, a phytic acid-doped polyaniline/graphite sheet (PA-PANI/GS) electrode is demonstrated for efficient uranium extraction from aqueous solutions by adsorption-electrodeposition strategy. The doping of phytic acid activates conductivity to intrinsic polyaniline, brings hydrophilicity and offers surface-specific binding sites for uranyl ions. The phosphate groups released from the PA-PANI/GS surface, the high electron transfer on the polyaniline chain, and the presence of Na+ allow the formation of (UO2)(3)(PO4)(2), (UO2)(3)(PO4)(2)center dot 4.8H(2)O and Na2O (UO3 center dot H2O)(x) precipitates during electrochemical deposition, which can easily be collected. The extraction capacity for uranium with the PA-PANI/GS is 1058 mg/g without reaching saturation. The reduction of the uranium concentration in spiked seawater from 3 mg/L to 29 ug/L is achieved with an extraction amount of about 266 ug within 36 h, which is below the US Environmental Protection Agency uranium limits for drinking water (30 ug/L). The PA-PANI/GS electrode after deposition cycles still recover more than 82 % of uranium through the "3 + 1" mode of physicochemical adsorption, which achieve maximum utilization in performance and economy. Low-energy of extraction processes and low-cost of electrode synthesis have many advantages in large-scale industrial applications.