Crystals of lead sulfate were precipitated in the solutions of various polyelectrolyte polymers (acidic, neutral and basic polymers) using a double-jet crystallizer. Polyetyleneimine (PEI), basic polymer, controlled both nucleation rate and crystal growth rate, and enabled to produce fine mono-dispersed crystals. The on-line measurement of the variation in the lead concentration indicated that PEI lost its effect, when a certain amount of the reactants (Ntot) was supplied. Interaction between lead ions and PEI was detected by NMR analysis, to suggest that lead ions made some kind of complex with PEI. The values of Ntot were correlated well with weight of PEI in the solution, regardless of the feed flow rate and reactant concentration, as shown in the correlative equation Ntot = k W0.49 (Figurel). It was suggested that PEI could no longer control the precipitation rate, when reactants were supplied over the amount of Ntot. And after that, the rapid nucleation occurred. Precipitation with PEI could be controlled by a certain amount of PEI in a ground solution in order to produce mono-dispersed fine crystals. These results idea would give an effective idea to crate various nm size crystals.
|出版ステータス||Published - 2005 11月 7|
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