Heavy metal ion sorption properties of porous glass beads with a core-shell structure

Porous glass beads with a core-shell structure have been successfully prepared through subcritical water treatment. The product has high capacity and fast mass transfer property due to its structure, and may serve as an inorganic adsorbent. Accordingly, the kinetics, the equilibrium isotherm, and the column breakthrough curve of this material were measured using Cu(II) as a model target ion. The results indicate that the material has an advantage over some other adsorbents, such as kaolinite and clinoptilolite, in both adsorption capacity and kinetics. The adsorption capacity for Cu(II) is almost twice as much as that of the Na-mordenite. The pseudo-second order kinetic and the Langmuir isotherm fit the experimental data. An adsorption mechanism was hypothesized in which the non-bridging oxygen ions in the glass network were hypothesized to be the functional site.