American Society of Civil Engineers


Sorption of Pb²+, Cd²+, and Sr²+ Ions on Calcium Hydroxyapatite Powder Obtained by the Hydrothermal Method


by S. Lazarevic´, (Master Student, Dept. of Inorganic Chem. Technol., Fac. of Technol., and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia. E-mail: nht@tmf.bg.ac.yu), I. Jankovic´-Castvan, (Master Student, Dept. of Inorganic Chem. Technol., Fac. of Technol. and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia. E-mail: nht@tmf.bg.ac.yu), D. Tanaskovic´, Ph.D., (Student, Dept. of Inorganic Chem. Technol., Fac. of Technol. and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia. E-mail: nht@tmf.bg.ac.yu), V. Pavic´evic´, (Sr. Teaching Asst., Dept. of Envir. Engrg., Fac. of Technol. and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia. E-mail: nht@tmf.bg.ac.yu), Dj. Janac´kovic´, (Assoc. Prof., Dept. of Inorganic Chem. Technol., Fac. of Technol., and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia. E-mail: nht@tmf.bg.ac.yu), and R. Petrovic´, (Asst. Prof., Dept. of Inorganic Chem. Technol., Fac. of Technol. and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia. E-mail: radaab@tmf.bg.ac.yu)

Journal of Environmental Engineering, Vol. 134, No. 8, August 2008, pp. 683-688, (doi:  http://dx.doi.org/10.1061/(ASCE)0733-9372(2008)134:8(683))

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Document type: Journal Paper
Abstract: The sorption of Pb²+, Cd²+, and Sr²+ ions from aqueous solutions by carbonate-substituted calcium hydroxyapatite (HAP) obtained by the hydrothermal decomposition of urea and calcium – ethylenediaminetetraacetic acid chelates was investigated. The shift of the point of zero charge (pHpzc) of HAP toward lower pH values in solutions of Pb²+ and Cd²+ ions, which was more pronounced for Pb²+ ions than for Cd²+ ions, indicates that specific adsorption of these cations on HAP had occurred. There was no shift of the pHpzc in the solution containing Sr²+ ions, suggesting that specific adsorption of this cation on HAP had not occurred. The sorption isotherms suggest that the sequence of the efficiency of sorption by HAP is Pb²+>Cd²+>Sr²+. Ion exchange is the main mechanism of removal of Sr²+ ions from aqueous solution by apatite, whereas during the sorption of Cd²+ ions, this mechanism occurs simultaneously with the process of specific adsorption. The interaction of the apatite with Pb²+ ions includes the previously mentioned mechanisms and dissolution of the apatite, followed by the precipitation of lead hydroxyapatite.


ASCE Subject Headings:
Ion exchange
Metals (chemical)
Sorption
Water quality