Adsorption of Pb(2+) ions on nanosized gamma-Fe(2)O(3): formation of surface ternary complexes on ligand complexation

Talanta. 2003 May 28;60(1):139-47. doi: 10.1016/S0039-9140(03)00119-X.

Abstract

Adsorption of Pb(2+) ions on the combustion derived nanosized gamma-Fe(2)O(3) and its thiourea complex composite is reported. The adsorbents upon adsorption of Pb(2+) ions are characterised by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray microanalysis and infrared spectroscopy techniques. The eluent is characterised by atomic absorption spectroscopy for the estimation of Pb(2+) ions. The reduction in the amount of lead after adsorption was estimated to be around 50% in case of complex composite adsorbent and around 15% in case of the gamma-Fe(2)O(3) adsorbents. Orthorhombic PbSO(4) precipitated out from the eluent and is reported with a model reaction. Adsorption of lead onto the complex composite is explained through the formation of a surface tertiary complex. The advantage of employing a thiourea-gamma-Fe(2)O(3) complex composite as solid adsorbent for the adsorption of heavy metal pollutants is envisaged in the present investigation.