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

Abstract

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)2·4.8H2O and Na2O(UO3·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.