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Synthesis and characterization of a bentonite-alginate microspherical adsorbent for removal of uranyl ions from aqueous Solutions

Tayyebi, A ; Sharif University of Technogy | 2010

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  1. Type of Document: Article
  2. DOI: 10.1080/01496390903255903
  3. Publisher: 2010
  4. Abstract:
  5. A novel microspherical adsorbent for the removal of uranium from aqueous solutions was developed by immobilizing of natural bentonite in the polymeric matrix of calcium alginate. Different uptake properties of the prepared microspheres were examined using batch, stirred and column methods. The adsorbent showed high affinity toward uranium ions, especially at pHs above 3. Major uptake mechanisms included ion exchange, chelating of the (UO2)2+ ions to the -OH groups of alginate, and surface complexation with bentonite. Surprisingly, the capacity of microspheres was higher than both its constituents, revealing that a synergetic effect occurs. Adsorption kinetics was controlled by slow chemical reaction of UO2 2+ ions with bentonite, and it obeyed a shrinking core model. Also a pseudo-second order chemical reaction fairly fitted the kinetics data. The synthesized microsphrese, in addition to cost efficiency, showed a relatively good column performance and high durability and reusability
  6. Keywords:
  7. Alginate microspheres ; Selectivity ; Synergetic effect ; Adsorption kinetics ; Aqueous solutions ; Calcium alginate ; Column methods ; Column performance ; Cost efficiency ; High affinity ; High durability ; Natural bentonite ; OH group ; Polymeric matrices ; Pseudo second order ; Shrinking core model ; Surface complexation ; Synthesis and characterization ; Uptake mechanism ; Uptake properties ; Uranium ion ; Reusability ; Bentonite ; Calcium ; Ions ; Microspheres ; Newtonian flow ; Reaction kinetics ; Synthesis (chemical) ; Transuranium elements ; Uranium ; Adsorption ; Alginate ; Chemical reaction ; Durability ; Ion exchange ; Matrix ; Shrinking ; Synthesis
  8. Source: Separation Science and Technology ; Volume 45, Issue 2 , 2010 , Pages 288-298 ; 01496395 (ISSN)
  9. URL: http://www.tandfonline.com/doi/abs/10.1080/01496390903255903