Zr(IV) structure in aqueous zirconium chloride octahydrate solution from small-angle X-ray scattering analysis

In this work, the dominant structures of Zr(IV) in zirconium oxychloride octahydrate solution were measured by using small-angle X-ray scattering (SAXS). The results show that the dominant structures of Zr.. are in the form of polymers in the solution, and the degrees of polymerization are susceptible to acidity. The different effects of the concentration, heating treatment, standing time, and HCl concentration of zirconium oxychloride in octahydrate were studied. With 0.0-5.0 mol.L-1 HCl as the solvent, 10-300 g.L-1 zirconium oxychloride solution was prepared, moreover, the solution was heated and placed for a long time respectively. The SAXS tests were carried out for all the solutions, and the R-g experiments of the particles in the solution were calculated using the Guinier equation. Meanwhile, the CYLview program for solving the most minor enclosing cylinder problems was used to simulate the different polymer structures of Zr(IV) in zirconium oxychloride octahydrate solution and obtain the theoretical R-g values of different structures. By comparing the experimental R-g and the calculated R-g, the dominant structures of Zr(IV) in solution under different conditions were obtained. The results show that the dominant structures of Zr(IV) are affected by many factors such as acidity and concentration, especially the concentration of HCl is the key factor affecting the degree of polymerization. When the solvent is deionized water, the polymerization degree of zirconium is relatively high in solutions with low zirconium concentration.