Removal of excess fluoride ions from Saharan brackish water by adsorption on natural materials

A. Ramdani, S. Taleb*, A. Benghalem, N. Ghaffour

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

81 Scopus citations


Water supply for people in the Sahara region is mainly assured by poor quality ground water which has excessive minerals, hardness and high concentration of fluoride. This leads to many teeth and bones diseases such as fluorosis. The purpose of this study is to eliminate the excess of fluorides from the El Oued Souf City water supply located in the South East of the Algerian Sahara by retention process onto montmorillonite clay using potentiometric method. Two types of natural clays were tested. The first one contains a higher percentage of calcium (AC) and the second one without calcium (ANC). These adsorbents were activated chemically and thermally with temperatures ranging between 200 and 500 °C. Experimental results showed that chemical activation proved effective adsorption reaching up to 88% whereas the thermal activation is ineffective and reached only around 5%. Moreover, the acidity of the medium and the alkalinity affect the adsorption considerably. The retention predicted from the adsorption isotherms is in agreement with Langmuir's model. The kinetic analysis of the reactions indicates that reaction is slow with diffusional control. The low values obtained for the heat of adsorption mean that the adsorption is exothermic with no specific type. An ionic mechanism exchange for fluoride removal is proposed in this study. Crown

Original languageEnglish (US)
Pages (from-to)408-413
Number of pages6
Issue number1
StatePublished - Jan 1 2010
Externally publishedYes


  • Adsorption
  • Clay
  • Desalination
  • Fluoride removal
  • Saharan brackish ground water

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • General Materials Science
  • Water Science and Technology
  • Mechanical Engineering


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