Adsorption equilibrium and kinetics of fluoride on sol-gel-derived activated alumina adsorbents

Lucy M. Camacho, Arely Torres, Dipendu Saha, Shuguang Deng

Research output: Contribution to journalArticlepeer-review

150 Scopus citations


Adsorption equilibrium and kinetics of fluoride on a sol-gel-derived activated alumina and its modifications with calcium oxide or manganese oxide were studied to explore the feasibility of applying these adsorbents for fluoride removal from drinking water. The activated alumina adsorbents were characterized with SEM/EDS and N2-adsorption for their chemical and pore textural properties. The adsorption isotherms were correlated with the Langmuir and Freundlich adsorption equations. The fluoride adsorption isotherms on the sol-gel-derived activated alumina followed the Freundlich model while the fluoride adsorption isotherms on the calcium oxide- or manganese oxide-modified activated alumina adsorbents followed the Langmuir model. The calcium oxide-modified alumina adsorbent showed the highest fluoride adsorption capacities of 0.99 and 96.23mg/g at fluoride concentrations of 0.99 and 432mg/L, respectively. A pseudo-second-order model and an intraparticle kinetic model fitted well the adsorption kinetic data. It was found that both external and intraparticle diffusions contribute to the rate of removal of fluoride from the activated alumina-based adsorbents produced in our laboratory. The adsorption kinetic models evaluated in this work fitted well the adsorption uptake of fluoride from a Mexican groundwater on both calcium oxide- and manganese oxide-modified alumina adsorbents.

Original languageEnglish (US)
Pages (from-to)307-313
Number of pages7
JournalJournal of Colloid And Interface Science
Issue number1
StatePublished - Sep 2010
Externally publishedYes


  • Activated alumina
  • Adsorption
  • Calcium oxide
  • Equilibrium
  • Fluoride
  • Kinetics
  • Manganese oxide

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry


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