Preparation and characterization of a new Ca/Fe-phosphate composite and its adsorption properties for uranyl ions

A new type of Ca/Fe-phosphate composite CFP(CN) was prepared by a sol–gel method. The effects of pH, reaction time, initial uranium concentration, reaction temperature, and Mn(II) selective adsorption were investigated by static batch experiments. The adsorption process of CFP(CN) on U(VI) was in line with the quasi-second-order kinetic model and the Langmuir adsorption isotherm model. The results of thermodynamic analysis show that the adsorption of U(VI) by CFP(CN) is a spontaneous process with heat absorption and entropy increase. The adsorption mechanism of U(VI) on CFP(CN) was investigated by SEM, XRD and FT-IR.