Potentiometric cell for measuring pH of supercritical aqueous solutions

Citation
K. Sue et al., Potentiometric cell for measuring pH of supercritical aqueous solutions, REV SCI INS, 72(12), 2001, pp. 4442-4448
Citations number
24
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences","Instrumentation & Measurement
Journal title
REVIEW OF SCIENTIFIC INSTRUMENTS
ISSN journal
0034-6748 → ACNP
Volume
72
Issue
12
Year of publication
2001
Pages
4442 - 4448
Database
ISI
SICI code
0034-6748(200112)72:12<4442:PCFMPO>2.0.ZU;2-P
Abstract
A flow-through electrochemical cell for subcritical and supercritical water systems was developed based on the cell of Lvov [J. Electroanal. Chem. 463 , 146 (1999)]. The cell consisted of two flow-through platinum hydrogen ele ctrodes and was constructed from a high nickel alloy (Hastelloy-B2). The in ner surface of electrochemical cell was coated with Al2O3 adhesive and cove red with the Al2O3 tube for corrosion resistance. Orifices were placed near the center of the cell to reduce concentration fluctuations around the tes t electrode. With the cell, a flow apparatus was used to measure the potent ials for HCl+NaCl aqueous solutions at supercritical conditions. The cell p otentials were measured at temperatures ranging from 23.9 to 400.2 degreesC and at pressures ranging from 25.0 to 35.1 MPa and the standard deviations of measured potentials were less than 0.4 mV for all tests. Comparison of the experimentally determined and theoretically calculated pH differences a re better than +/-0.03 logarithmic units over the range of conditions studi ed. (C) 2001 American Institute of Physics.