Facile Synthesis of Phytic Acid Impregnated Polyaniline for Enhanced U(VI) Adsorption

A novel phytic acid impregnated polyaniline (PA-PANI) was synthesized by a in situ polymerization and supermolecular self-assembly method and has been used as an adsorbent for efficient capture of U(VI) from aqueous solution. The structure and morphology of the adsorbent were well characterized. The influence of different factors such as pH value, ionic strength, contact time, initial U(VI) concentration and temperature on the adsorption of U(VI) onto PA-PANI-3 were carried out by batch adsorption experiments. The results demonstrated an enhanced U(VI) adsorption capacity of 86.6 mg/g for PA-PANI-3, greatly exceeding that of polyaniline (PANI, 8.8 mg/g). The adsorption process follows the pseudo-second order kinetic and Langmuir isotherm models with the theoretical maximum adsorption capacity of 90.3 mg/g. According to the calculation from the Dubinin-Radushkevich isotherm model equation, it is suggested that the adsorption is mainly a chemical adsorption mechanism. U(VI) is adsorbed on PA-PANI-3 via the phosphoric acid, amine, and imine groups. The U(VI) can be desorbed from the U(VI) adsorbed PA-PANI-3 with a desorption efficiency of 90.8% by using 0.1 mol/L Na2CO3 solution. This study demonstrated that PA-PANI could be used as an efficient adsorbent for removal and recovery of U(VI) from aqueous solution.