Electroactive magnetic microparticles for the selective elimination of cesium ions in the wastewater

To improve operability as well as the removal efficiency for cesium ions in the wastewater treatment, a novel electrochemically switched ion exchange (ESIX) technique by using electroactive Prussian-blue(PB)-based magnetic microparticles (PB@Fe3O4 microparticle) with different uniform particle sizes in the range of 300-900 nm as the adsorption materials was developed. The obtained PB@Fe3O4 microparticle were characterized by Scanning electron microscopy (SEM), Transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Thermogravimetric analysis (TGA). It is found that the PB can be well coated on the surface of Fe3O4 microsphere, which can be easily adsorbed on the magnetic electrode substrate for the electrochemical adsorption of Cs+ ions. Electrochemical adsorption of 97% Cs+ on PB/Fe3O4 was achieved in less than 10 min, and the maximum adsorption capacity was 16.13 mg/g, and the distribution coefficient (KD) of Cs+ ions reached as high as 3938. In addition, the electrochemical adsorption behavior of PB@Fe3O4 microparticle fitted well with the Freundlich adsorption isotherm and the Pseudo-second-order kinetic models. It is expected that such an ESIX technique using PB@Fe3O4 microparticle can be applied for the separation and recovery of dilute Cs+ ions from cesium-contaminated solution in a practical process.