Preparation of zirconium phosphate (ZrP)/Nafion1135 composite membrane and H+/VO2+ transfer property investigation

The zirconium phosphate (ZrP)/Nafion1135 composite membranes were prepared by impregnating method and characterized by SEM, XRD, ac impedance and electron probe microanalysis (EPMA) techniques. The results show that ZrP(α-Zr(HPO4)2·H2O) deposited both on Nafion1135 membrane surface and in its inner structure, and the amount of deposited ZrP increases with the immersion time. A test of membrane resistance shows that the membrane resistance increases with the immersion time greatly in image = 0.009:0.1 mol L−1 H2SO4 + VOSO4 solution than in 0.05 mol L−1 H2SO4 solution. Subsequently, the proton diffusion coefficient image and VO2+ diffusion coefficient image in membrane are evaluated. It is found that both image and image decrease with the immersion time based on the retarding effect of the deposited ZrP. The proton diffusion coefficient in Nafion1135 was determined to be 3.412 × 10−12 m2 s−1, and a slightly lower value of 2.827 × 10−12 m2 s−1 was found in Nafion1135/ZrP5 membrane. However, the VO2+ diffusion coefficient image of the Nafion1135 membrane, 4.012 × 10−13 m2 s−1, is much higher than that of 1135/ZrP5 composite membrane, 0.3226 × 10−13 m2 s−1. The results show that the composite membrane has better permselectivity as to H+ and VO2+ than Nafion®1135 membrane.