MSA  Vol.2 No.11 , November 2011
Fluoride Adsorption onto Acid-Treated Diatomaceous Mineral from Kenya
Abstract: Acid treated diatomaceous earth (ATDE) from a mining site in Kenya was evaluated for its removal of F from aqueous solutions using adsorption batch experiments. The effect of initial F concentration, adsorbent dosage, contact time, temperature, pH and competing anions was studied. The adsorption process was very fast reaching an initial equilib- rium in just 10 min. Fluoride adsorption onto ATDE increased strongly from just about 40% to over 92% when the solution temperature was raised from 293 to 303 K. The process was however, almost unresponsive to pH changes drop- ping by a margin of < 1% from 98.8% to 98% when the solution pH was raised from 1.59 to 6.89. It was obvious therefore that increase in concentration of OH- ions does not affect F adsorption onto ATDE. More so apart from the Cl- ions which marginally reduced F adsorption onto ATDE, there was no obvious effect of the SO42- , NO3- and PO43- ions on F uptake by ATDE. Complete F removal (100% adsorption) could be achieved at 400 mg/L initial F concentra- tions using 0.5 g/mL ATDE batch loading ratio at 303 - 313 K and pH = 3.4 ± 0.2. The F adsorption iso- therm was well correlated to the Freundlich and Langmuir models and could be classified as H-Type according to Giles classification of isotherms. The maximum Langmuir F adsorption capacity of ATDE was 51.1 mg/g. It has been demonstrated that a diatomaceous mineral from Kenya could be use as an inexpensive adsorbent for the removal of F ions from aqueous streams.
Cite this paper: nullE. Wambu, C. Onindo, W. Ambusso and G. Muthakia, "Fluoride Adsorption onto Acid-Treated Diatomaceous Mineral from Kenya," Materials Sciences and Applications, Vol. 2 No. 11, 2011, pp. 1654-1660. doi: 10.4236/msa.2011.211220.

[1]   World Health Organization, “WHO Chemical fact sheets: Fluoride,” Vol. 1, 3rd Edition, WHO, Geneva, 2006, pp. 375-377.

[2]   G. L. Waldbott, “Systematic Poisons: Fluoride and Cad- mium,” In G. L. Waldbott, Ed., Health Effects of Environ- mental Pollutants, 2nd Edition, C. V. Mosby Company, St. Louis, 1978, pp. 150-168.

[3]   A. A. Yates, S. A. Schlicker and C. W. Suitor, “Food and Nutrition Board, Institute of Medicine, National Academy of Sciences. Dietary Reference Intakes: The New Basis for Recommendations for Calcium and Related Nutrients, B Vitamins, and Choline,” Journal of American Dietetic Association, Vol. 98, No. 6, 1998, pp. 699-706. doi:10.1016/S0002-8223(98)00160-6

[4]   C. Reimann, K. Bjorvatn, B. Frengstad, Z. Melaku, R. T. Haimanot and U. Siewers, “Drinking Water Quality in the Ethiopian Section of the East African Rift Valley I—Data and Health Aspects,” The Science of the Total Environ- ment, Vol. 311, No. 1-3, 2003, pp. 65-80. doi:10.1016/S0048-9697(03)00137-2

[5]   E. W. Wambu and G. K. Muthakia, “High Fluoride Water in the Gilgil Area of Nakuru County, Kenya,” Fluoride, Vol. 44, No. 1, 2011, pp. 37-41.

[6]   S. K. Nath and R. K. Dutta, “Fluoride Removal from Wa- ter Using Crushed Limestone,” Indian Journal of Chemi- cal Technology, Vol. 17, 2010, pp. 120-125.

[7]   S. A. Esmaili, A. S. Nasseri, A. R. Mahvi and R. Atash- Dehghan, “Adsorption of Lead and Zinc Ions from Aque- ous Solution by Volcanic Ash Soil,” 2003.

[8]   Y. Vijaya and A. Krishnaiah, “Sorptive Response Profile of Chitosan Coated Silica in the Defluoridation of Aque- ous Solution,” E-Journal of Chemistry, Vol. 6, No. 3, 2009, pp. 713-724.

[9]   G. Karthikeyan, A. Shanmuga Sundarraj, S. Meenakshi and K. P. Elango, “Adsorption Dynamics and the Effect of Temperature of Fluoride at Alumina Solution In- terface,” Journal of the Indian Chemical Society, Vol. 81, No. 6, 2004, pp. 461-466.

[10]   Y. Ku and H. Chiou, “The Adsorption of Fluoride Ion from Aqueous Solution by Activated Alumina,” Water, Air and Soil Pollution, Vol. 133, No. 1-4, 2002, pp. 249- 361.

[11]   G. Alagumuthu, V. Veeraputhiran and R. Venkataraman, “Fluoride Sorption Using Cynodon dactylon-Based Acti- vated Carbon,” Hemijska Industrija, Vol. 65, No. 1, 2011, pp. 23-35. doi:10.2298/HEMIND100712052A

[12]   A. V. Jamode, V. S. Sapkal, V. S. Jamode and S. K. Deshmukh, “Adsorption Kinetics of Defluoridation Using Low-Cost Adsorbents,” Adsorption Science & Tech- nology, Vol. 22, No. 1, 2009, pp. 65-73. doi:10.1260/026361704323151006

[13]   M. Karthikeyan, V. Gopal and K. P. Elango, “Adsorption of Fluoride Ions onto Naturally Occurring Earth Mate- rials,” Journal of Applied Sciences and Environmental Management, Vol. 14, No. 4, 2010, pp. 90-95.

[14]   C. H. Weng, C. Z. Tsai, S. H. Chu and Y. C. Sharma, “Adsorption Characteristics of Copper (II) onto Spent Activated Clay,” Separation and Purification Technology, Vol. 54, No. 2, 2007, pp. 187-197. doi:10.1016/j.seppur.2006.09.009

[15]   S. Ho, D. A. J. Wase and C. F. Forster, “Batch Nickel Removal from Aqueous Solution by Sphagnum Moss Peaty,” Water Research, Vol. 29, No. 5, 1995, pp. 1327- 1332. doi:10.1016/0043-1354(94)00236-Z

[16]   E. W. Wambu, G. K. Muthakia, J. K. Wa-Thiong’o and P. M. Shiundu, “Kinetics and Thermodynamics of Aqueous Cu(II) Adsorption on Heat Regenerated Spent Bleaching Earth,” Bulletin of the Chemical Society of Ethiopia, Vol. 25, No. 2, 2011, pp. 1-10.

[17]   J. Zhang, S. Xie and Y. S. Ho, “Removal of Fluoride Ions from Aqueous Solution Using Modified Attapulgite as Adsorbent,” Journal of Hazardous Materials, Vol. 165, No. 1-3, 2009, pp. 218-222. doi:10.1016/j.jhazmat.2008.09.098

[18]   R. N. Yadav, O. P. Singh and R. Yadav, “Study of the Aluminum Ammonium Sulphate as Defluoridated Agent in Drinking Water Earthenware,” Archives of Applied Science Research, Vol. 2, No. 3, 2010, pp. 11-22.

[19]   G. Karthikeyan, A. Pius and G. Alagumuthu, “Fluoride Adsorption Studies of Montmorillonite Clay,” Indian Journal of Chemical Technology, Vol. 12, No. 3, 2005, pp. 263-272.

[20]   S. Janta, S. Watanesk, R. Watanesk and S. Thiansem, “Cost Effective Natural Adsorbent for Fluoride Re- moval,” Advanced Material Research, Vol. 55-57, 2008, pp. 865-868. doi:10.4028/