Abstract
In this study, solubility behavior of lead magnesium niobate (PMN) powders in water was investigated in the presence of pure polyacrylic acid and polyacrylic acid/polyethylene oxide comb polymers. Experiments were performed by measuring the solubility of PMN in terms of the concentration of Pb+2 and Mg+2 ions in supernatant as a function of pH and dispersing agent dosage. The concentrations of the metal ions in supernatant were found to be affected by the dispersant concentration, stirring time and the suspension pH. Results revealed that both dispersing agents enhance the cation dissolution from PMN surface at pH 9 due to weak (reversible) adsorption and complexation of Pb+2 and Mg+2 by carboxylate groups. On the other hand, under acidic conditions cation dissolution from PMN is inhibited and this was attributed to the strong adsorption of dispersing agents onto the powder surface and formation of a dense polymer layer.
Acknowledgments
The authors would like to thank Prof. Dr. Jennifer A. Lewis for her support and contributions and Environmental Research Center at Izmir Institute of Technology for use of the ICP-AES. Dynamic light scattering measurements were performed in University of Illinois at Urbana Champaign, Materials Science and Engineering Department. The grant by The Scientific and Technological Research Council of Turkey (Tubitak NATO-A2) is gratefully acknowledged.