Influence of Dispersing Agents on the Solubility of Perovskites in Water

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 þ2 and Mg þ2 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 þ2 and Mg þ2 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.

Flow behavior of hydroxypropyl methyl cellulose/polyacrylic acid interpolymer complexes in aqueous media

“…Because both screening efficiency and bridging interactions intensify with increasing counter-ion valency, divalent counter-ions are more effective at promoting attractions between polyelectrolyte species than monovalent counter-ions. 28,29 The previous study of Şakar-Deliormanlı et al 30 showed that under fully ionized conditions (at pH 9) MgCl 2 -containing PAA solutions were only stable in the range (0-2) ×10 −2 mol L −1 MgCl 2 . At higher salt concentrations PAA starts to make complexes with Mg 2+ ions in solution and turbidity increases.…”

“…The previous study of Şakar‐Deliormanlı et al showed that under fully ionized conditions (at pH 9) MgCl 2 ‐containing PAA solutions were only stable in the range (0–2) × 10 −2 mol L −1 MgCl 2 . At higher salt concentrations PAA starts to make complexes with Mg 2+ ions in solution and turbidity increases.…”