Defluoridation of drinking water using activated titanium rich bauxite.

The potential of thermally activated titanium rich bauxite (TRB) for adsorptive removal of excess fluoride from drinking water was examined. Adsorption with respect to variation of pH, adsorbent dose, initial fluoride concentration, presence of interfering ions and heat treatment were investigated by batch equilibrium experiments. Thermal activation at moderate temperatures (300-450 degrees C) greatly increased the adsorption capacity of TRB. The rate of adsorption was rapid and maximum level was attained within 90 min. The uptake of fluoride increased with increasing pH, reached to a maximum at pH 5.5-6.5 and thereafter decreased. The adsorption kinetics was found to follow first order rate expression and the experimental equilibrium adsorption data fitted reasonably well to both Langmuir and Freundlich isotherm models. The presence of common interfering ions in drinking water did not greatly affect the uptake of fluoride from aqueous solution indicating F specific sorption behaviour of TRB. Nearly complete desorption of adsorbed fluoride from loaded bauxite was achieved by treating with aqueous solutions of pH > or =11.1 ([NaOH] > or =0.015 mol/dm(3)).

[1]  Y. Ku,et al.  The Adsorption of Fluoride Ion from Aqueous Solution by Activated Alumina , 2002 .

[2]  J. A. Schwarz,et al.  Estimation of the point of zero charge of simple oxides by mass titration , 1989 .

[3]  J. Karthikeyan,et al.  A study on removal of fluorides from drinking water by adsorption onto low-cost materials. , 1998, Environmental pollution.

[4]  H. S. Altundoğan,et al.  Removal of hexavalent chromium by using heat-activated bauxite , 2004 .

[5]  A. Pauss,et al.  Fluoride removal with electro-activated alumina , 2004 .

[6]  H. Kay.  Environmental Health Criteria , 1980 .

[7]  Ji Liang,et al.  Preparation of alumina supported on carbon nanotubes and its application in fluoride adsorption from an aqueous solution , 2002 .

[8]  E. Underwood.  Trace Elements in Human and Animal Nutrition , 1956, Agronomy Journal.

[9]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[10]  B. B. Johnson,et al.  The effect of temperature and pH on the adsorption of copper(II), lead(II), and zinc(II) onto goethite , 1993 .

[11]  C. D. Cox,et al.  Adsorption of selenium on hydrous alumina , 1994 .

[12]  R. Qi,et al.  Precipitative Removal of Fluoride from Electronics Wastewater , 2001 .

[13]  Takahiro Kojima,et al.  Photocatalytic reduction of selenate and selenite solutions using TiO2 powders , 1999 .

[14]  Yanxin Wang,et al.  Activation and regeneration of a soil sorbent for defluoridation of drinking water , 2001 .

[15]  Jing Zhao,et al.  Preparation and Defluorination Performance of Activated Cerium(IV) Oxide/SiMCM-41 Adsorbent in Water. , 2001, Journal of colloid and interface science.

[16]  Thakur,et al.  Removal of Fluoride from Aqueous Solution by Using Alum Sludge. , 1998, Journal of colloid and interface science.

[17]  S. Faust,et al.  Adsorption processes for water treatment , 1987 .

[18]  Y. Ku,et al.  The removal of fluoride ion from aqueous solution by a cation synthetic resin , 2002 .

[19]  T. Ruiz,et al.  Modelisation of fluoride removal in Donnan dialysis , 2003 .

[20]  D. Mishra,et al.  Use of oxide minerals to abate fluoride from water. , 2004, Journal of colloid and interface science.

[21]  D. Parker,et al.  Adsorption kinetics of fluoride on low cost materials. , 2003, Water research.

[22]  Mehmet Mahramanlıoğlu,et al.  Adsorption of fluoride from aqueous solution by acid treated spent bleaching earth , 2002 .

[23]  Meetu Agarwal,et al.  Defluoridation of Water Using Amended Clay , 2003 .

[24]  A. Raichur,et al.  Adsorption of fluoride onto mixed rare earth oxides , 2001 .

[25]  A. Gupta,et al.  Development of new low cost defluoridation technology (krass) , 1999 .

[26]  Kulamani Parida,et al.  Physicochemical characterization and adsorption behavior of calcined Zn/Al hydrotalcite-like compound (HTlc) towards removal of fluoride from aqueous solution. , 2003, Journal of colloid and interface science.

[27]  Kamal K. Pant,et al.  Investigations on the column performance of fluoride adsorption by activated alumina in a fixed-bed , 2004 .

[28]  Yan-xin Wang,et al.  A Limestone Reactor for Fluoride Removal from Wastewaters , 2000 .

[29]  D. Killedar,et al.  Fluoride adsorption on fishbone charcoal through a moving media adsorber , 1992 .