Inkjet-based facile fabrication of a copper ferrocyanide-embedded magnetic alginate microadsorbent for highly enhanced cesium removal

For the first time, simple and facile fabrication of a magnetic alginate microadsorbent via piezoelectric inkjet technology was developed for the selective removal of ¹³⁷Cs via magnetic separation. Through the ejection of an alginate solution containing potassium ferrocyanide and magnetic nanoparticles (MNPs) into a Cu²⁺ solution via an inkjet device, the fabrication of a copper ferrocyanide-embedded magnetic alginate microadsorbent (CuFC-MAM) with an average size of 39.38 μm was easily achieved in a one-pot fabrication process; here, the Cu²⁺ ions acted as both a cross-linker for the gelation of alginate and a Cu source for the in situ synthesis of CuFC with potassium ferrocyanide. The Cs adsorption behavior of CuFC-MAM was effectively fitted by the pseudo-second-order kinetic model and Langmuir isotherm. Owing to the increased specific surface area of CuFC-MAM, its pseudo-second-order rate constant and maximum adsorption capacity were 76.54 and 1.486 times greater than those of CuFC-embedded magnetic alginate macroadsorbents fabricated without inkjet devices. Compared with other Cs adsorbents, CuFC-MAM presented the highest maximum capacity and K_d value; these results were attributed to the high content of CuFC in CuFC-MAM (50.15%). In addition, our CuFC-MAM exhibited an excellent removal efficiency of radioactive Cs, exceeding 99% from seawater.