In:
Annali di Chimica, Wiley, Vol. 95, No. 9-10 ( 2005-09), p. 643-656
Abstract:
The protonation of polyacrylate (PAA, MW 2 kDa) was studied potentiometrically at 25 °C, in mixed electrolyte aqueous solution simulating the composition of seawater, in the salinity range 30 ≤ S ≤ 40. The salt composition of different solutions was varied in order to study its effect on apparent protonation constants. Results were analysed using two fairly different approaches: by simple regression analysis on a combination of concentration parameters and salinity, and by canonical correlation analysis. Unexpectedly we found that variations on protonation constants, due to the different relative component concentrations, are fairly low, revealing a sort of buffering capacity of seawater respect to protonation properties of polyacrylate (and likely for other HMW and LMW polycarboxylates). The intrinsic protonation constant of polyacrylate 2 kDa at 25 °C and 35 salinity is ${\rm log} \bar K^{\rm H^\ast} = {\rm log} K_{\rm int} = 4.399 \pm 0.004$ . The use of different pH scales and standard seawater compositions is also discussed.
Type of Medium:
Online Resource
ISSN:
0003-4592
,
1612-8877
DOI:
10.1002/adic.v95:9/10
DOI:
10.1002/adic.200590075
Language:
English
Publisher:
Wiley
Publication Date:
2005
