Adsorptive removal of Pb(II) from aqueous solution using nano-sized hydroxyapatite

S T Ramesh,R Gandhimathi,N Rameshbabu,P V Nidheesh,M Srikanth Kumar

doi:10.1007/s13201-012-0064-z

S T Ramesh, R Gandhimathi + Show 3 more

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https://doi.org/10.1007/s13201-012-0064-z

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Abstract

This study investigated the sorption of Pb(II) in aqueous solution onto hydroxyapatite (HA) surfaces. Batch experiments were carried out using synthetic HA. The effect of contact time, HA dosage, and initial pH on removal efficiency were also investigated. The adsorption equilibrium and kinetics of Pb(II) on this adsorbent were then examined at 25 °C. Kinetic data were analyzed by pseudo first, second, and intra-particle diffusion models. The sorption data were then correlated with the Langmuir, Freundlich, Halsey, and Harkins–Jura adsorption isotherm models. The optimum dose of HA for Pb(II) removal is found to be 0.12 g/l with the removal efficiency of 97.3 % at an equilibrium contact time of 1 h. It is found that the adsorption kinetics of the Pb(II) on HA follow the pseudo second-order reaction. All the isotherms fitted well for experimental data. Capacity of HA is found as 357.14 mg Pb(II)/g of HA. The Pb(II) immobilization mechanism was studied. The results indicated that HA can be used as an effective adsorbent for removal of Pb(II) from aqueous solution.

Highlights

This study investigated the sorption of Pb(II) in aqueous solution onto hydroxyapatite (HA) surfaces
The sorption data were correlated with the Langmuir, Freundlich, Halsey, and Harkins–Jura adsorption isotherm models
It is found that the adsorption kinetics of the Pb(II) on HA follow the pseudo second-order reaction

Summary

Introduction

This study investigated the sorption of Pb(II) in aqueous solution onto hydroxyapatite (HA) surfaces. Drinking water containing Pb(II) ions for a long term, even if in a very low concentration, cause a wide range of spectrum health problems, such as renal failure, coma, nausea, cancer, convulsions and subtle effects on metabolism and intelligence (Rashed 2001; Li et al 2005). It can cause mental retardation and semipermanent brain damage in young children (Mohammad and Najar 1997). Among the various water-treatment techniques described, adsorption is generally preferred for the removal of heavy metal ions due to its high efficiency, easy handling, availability of different adsorbents, and cost effectiveness (Beauvais and Alexandratos 1998). The most widely studied adsorbent is activated carbon, while the application of other adsorbent materials for metal-ion removal is receiving considerable attention (Corami et al 2007)

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