BACKGROUND: The retention behaviour of Pb(II) by hematite was studied as a function of various environmental parameters such as contact time, pH, ionic strength, foreign ions, humic substances and temperature under ambient conditions.
RESULTS: Pb(II) sorption on hematite was rapid and the sorption could be described by a pseudo-second-order model very well. The sorption of Pb(II) on hematite was strongly dependent on pH and ionic strength. The presence of humic substances enhanced the sorption of Pb(II) on hematite at low pH, but reduced Pb(II) sorption at high pH. The Langmuir model fitted the sorption isotherms of Pb(II) better than the Freundlich model at three different temperatures, 293.15, 313.15 and 333.15 K. The thermodynamic parameters (ΔH°,ΔS° and ΔG°) calculated from the temperature dependent sorption isotherms indicated that the sorption process of Pb(II) on hematite was endothermic and spontaneous.
CONCLUSIONS: The results indicate that hematite is a promising candidate for the treatment of heavy metal ions from large volume solution. Copyright © 2011 Society of Chemical Industry