Adsorption of Cl- ion with pyrolysis products of yttrium oxynitrate hydrate, Y2(OH)6-x(NO3)x·nH2O

We attempted adsorption of Cl- ion in HCl and NaCl solutions with compounds which were prepared by heating yttrium oxynitrate hydrate, Y2(OH)6-x(NO3)x·H2O up to 600degC. The X-ray powder diffraction patterns of the compounds obtained by heating up to 200degC was the same as that of Y2(OH)6-x(NO3)x·H2O; however, it changed to YONO3 in the temperature range from 300 to 400degC and finally changed to Y2O3 above 500degC. In 0.1 M NaCl solution the starting compound and its pyrolysis products little incorporated Cl- ion. On the contrary, in 0.1 M HCl solution the uptake of Cl- ion increased with the treatment temperature, and the maximum value was 3.1 mequiv g-1 for samples heated above 500degC. (author)