The effect of temperature on the sorption of U(VI) onto ZrP2O7 in the presence of oxalic acid

The sorption of uranium onto ZrP2O7 in the presence of oxalic acid has been investigated as a function of temperature (20, 40 and 60 deg C). Using several complementary analytical methods to characterize the solid surface, it has been shown that the oxalic acid interact with the zirconium diphosphate affecting its surface reactivity. A significant influence of temperature on the sorption reaction has been revealed in the batch experiments. Temperature dependence sorption data and microcalorimetric measurements have been used to determine enthalpy change associated to the sorption reaction. The results have shown that oxalic acid has an important effect on uranium sorption, which is more evident at 60 deg C. (author)