Abstract
The hydrous oxides of metallic elements are known to adsorb some ion species in aqueous media. In this study, ten Si-Al-Mg mixed hydrous oxide samples were synthesized using various Si, Al and Mg molar ratios, and the adsorption properties of these samples were evaluated in terms of ion adsorption rate. The adsorption equilibrium was attained only within 8 hours and completed at 24 hours for most of the prepared adsorbents. In particular, adsorbent No. 10, for which the molar ratio of Si-Al-Mg = 0.1:0.1:0.8, the greatest Mg ratio in the 10 adsorbents, was found to uptake large amounts of arsenite and phosphate ions. The Freundlich equation could be successfully applied to the isotherms for fluorine, boron, arsenate, arsenite, phosphate, selenate and selenite ions. The Freundlich parameter of 1/n ranged 0.1 – 0.5 for adsorbent No. 10 indicating that harmful ions could be easily removed from aqueous solution in broad concentration range.
