Browsing by Author "Getachew, Girum"

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    Zeolites and Mixed Oxides in the Removal of Cr (Vi)
    (Addis Ababa University, 2014-06-06) Getachew, Girum; Diaz, Isabel (Professor); Pérez, Eduardo (PhD)
    In this work, different natural zeolites, namely Clinoptilolite (Mexico) and Sample 7 (Ethiopia), mesoporous material SBA-15 calcined and uncalcined as well as mixed oxides Hydrotalcite and SBA-15 supported hydrotalcite were employed for removal of chromate from aqueous solution. This materials show adsorption capacity with different mechanisms and ion (cation and anion) exchange properties. UV-Vis spectroscopy was used for determining the concentration of Cr (VI) before and after the treatment. Obtained data from chromate adsorption experiments over the mentioned materials were compared. It was shown that adsorption data for natural zeolite was very good having 66.5% and 74.5% adsorption capacity for Clinoptilolite and Sample 7, respectively. Maximum chromate adsorption was found over mixed oxides: 98.4% and 88.7% for SBA-15/HT and HT, respectively. It was much greater than that of the natural zeolites and mesoporous materials. For comparison purpose, pure silica mesoporous materials calcined and uncalcined SBA-15 were tested, showing retaining capacity of 13.6% and 39.89%, respectively. Finally, SBA-15/HT composite appears as a promising adsorbent for removal of chromate ion from waste waters.