Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Ion-exchange properties of ion-sieve-type manganese oxides prepared by using different kinds of introducing ions

Journal Article · · Sep. Sci. Technol.; (United States)
Three ion-sieve-type manganese oxides, HMnO(Li), HMnO(Na), and HMnO(K), were prepared by acid treatment of Li/sup +/-, Na/sup +/-, and K/sup +/-introduced manganese oxides, respectively. Three oxides were obtained from ..gamma..-MnO/sub 2/ and the corresponding alkali metal hydroxides by heating at 600/sup 0/C. The ion-exchange properties of the adsorbents were investigated by pH titration, K/sub d/ measurements, and the adsorption of metal ions from seawater. The selectivity sequences of alkali metal ions were Na/sup +/ < Cs/sup +/ < Rb/sup +/ < K/sup +/ < Li/sup +/ for HMnO(Li) and Li/sup +/ approx. = Na/sup +/ < Cs/sup +/ < K/sup +/ < Rb/sup +/ for HMnO(Na) and HMnO(K). The high selectivity of Li/sup +/ on HMnO(Li) can be ascribed to an ion-sieve effect of spinel-type manganese oxide which was produced from LiMn/sub 2/O/sub 4/. Since HMnO(Na) and HMnO(K) had (2 x 2) tunnels of edge-shared (MnO/sub 6/) octahedra, the high selectivities of K/sup +/ and Rb/sup +/ on these samples were used to explain that the sizes of the (2 x 2) tunnels were suitable for filling ions of about 1.4 A in radius in a stable configuration. The order of metal-ion uptake from seawater was Sr/sup 2 +/ < K/sup +/ < Mg/sup 2 +/ < Ca/sup 2 +/ < Na/sup +/ < Li/sup +/ for HMnO(Li), Li/sup +/ < Sr/sup 2 +/ < Mg/sup 2 +/ < Ca/sup 2 +/
Research Organization:
Government Industrial Research Institute, Kagawa (Japan)
OSTI ID:
5183191
Journal Information:
Sep. Sci. Technol.; (United States), Journal Name: Sep. Sci. Technol.; (United States) Vol. 22:7; ISSN SSTED
Country of Publication:
United States
Language:
English