NaPAA

Sodium polyacrylate (NaPAA) [9003-04-7]. Commercial polyacrylamide was neutralised with an aqueous solution of NaOH and the polymer ppted with acetone. The ppte was redissolved in a small amount of water and freeze-dried. The polymer was repeatedly washed with EtOH and water to remove traces of low... 

Fig. 15. Comparison of the experimental data for the polyelectrolyte effect on ki of NH4-OCN reaction at 50 °C with the theoretical curves obtained from eq. 16. O NaPAA added, [NH4OCN] = 0.0205 M, O DECS added, [NH4OCN] = 0.1025 M (Ref.15 ))...

Analytical grade NaCl, polyvinylchloride (Aldrich, high mol. wt.), bls(2-ethylhexyl)phtalate (GR, Aldrich), and tetrahydrofuran (AR, BDH Chemicals) were used without further purification. Polyacrylic acid, mol. wt. 250,000 (Aldrich) was titrated with NaOH to obtain a stock solution of NaPAA of known carboxylate concentration. 

For all radioisotopes present in the waste sample DFs, in the case where cyanoferrate and chelating polymer were applied subsequently in two-stage process, were higher than those obtained when the complexing agents were added to the feed solution simultaneously. All decontamination factors were higher than DFs obtained for a single soluble polymer (NaPAA or PEI) (Table 30.9). 

The membrane performance was good, during almost 60-h operation and the permeate flux was stable after initial decline. The biggest flux decrease was observed when macromolecular sodium polyacrylate was introduced first after dosing 0.4 g/L of NaPAA, then after injection of the next portion (1 g/L NaPAA). In that time, permeate flux declined from 52 L/m h in the beginning (without the complexing agent), to 11 L/m h after injection of 1 g/L of the polymer. Further increase of polymer concentration did not result in the flux decline, as well as addition of CoCF suspension. 

FIGU RE 25.11 DFs for europium-152 in function of concentration of NaPAA (M = 8000), Membralox 5 kDa, 0.5 g/L EujOj, and pH 8. (Reprinted from J. Membr. ScL, 225, Zakrzewska-Trznadel, G., Radioactive solutions treatment by hybrid complexation—UF/NF process, 25-39, Copyright 2003, with permission from Elsevier.)... 

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