Simultaneous removal of Cs(I) and U(VI) by a novel magnetic AMP@PDA@Fe3O4 composite

Abstract

The development and use of clean energy produced by nuclear power plants is becoming a major international trend, but it will inevitably lead to the problem of radionuclide pollution. Radioactive nuclear wastewater containing Cs and U and produced as a byproduct of coastal nuclear power production can cause substantial environmental pollution. In order to simultaneously remove radioactive cesium and uranium, polydopamine (PDA) inlaid ammonium phosphomolybdate (AMP) has established a hydrophilic functional structural film on the surface of Fe3O4, forming AMP@PDA@Fe3O4 (APF) which is used to simultaneous remove Cs(I) and U(VI). Using the pH sensitive range of APF adsorption in the process of adsorbing Cs(I) and U(VI), synergistic adsorption can be achieved under the condition of weak acidity to neutral. The effects of temperature, and common cations on Cs(I) and U(VI) adsorption by APF were investigated, the adsorption was found to be sensitive to the presence of K+. The efficiency of Cs(I) and U(VI) adsorption by APF was 99.88% and 98.39%, respectively. The Cs(I) adsorption process was primarily ion exchange with NH4+ within APF composite, whereas that for U(VI) was primarily C-O complexation. Both the Cs(I) and U(VI) adsorption reactions were consistent with second-order kinetic and Langmuir isothermal adsorption models. After five cycles of experiments the removal efficiency of Cs(I) and U(VI) can reach 64.88% and 79.81%, respectively. APF was also found to have high selectivity for Cs and U in seawater with high salt content at pH 6.0–7.0. In mimic contaminated seawater, the efficiency of Cs(I) and U(VI) removal was 97.65% and 84.63%, respectively. These findings provide references for the remove of Cs(I) and U(VI) from radioactive wastewater, making the process of energy production safer.