TY - JOUR
T1 - Potentiometric pH measurements in high subcritical and supercritical aqueous solutions
AU - Lvov, S. N.
AU - Gao, H.
AU - Kouznetsov, D.
AU - Balachov, I.
AU - Macdonald, D. D.
N1 - Funding Information:
The authors gratefully acknowledge the support of this work by the Electric Power Research Institute (Contract #WO8031-04) and the National Science Foundation (NSF Grant EAR 9725191). The authors thank H.L. Barnes for helpful discussions during the course of this study.
PY - 1998
Y1 - 1998
N2 - An operational electrochemical thermocell is proposed for potentiometric pH measurements in high subcritical and supercritical aqueous solutions. The thermocell consists of the silver-silver chloride flow-through external pressure-balanced reference electrode (FTEPBRE) and the flow-through platinum-hydrogen pH sensor. Using this thermocell we have measured the potentials of the thermocell fora few HC1(aq) and NaOH(aq) solutions of different concentrations and derived the corresponding pH differences (ΔpH) over a wide range of temperatures from 25 to 400°C at pressures between 27.5 and 33.8 MPa. Comparison of the experimentally derived and theoretically calculated ΔpH values clearly demonstrates an ability of the thermocell to measure pH with accuracy better than ±0.1 units, and this result in turn demonstrates the viability of the FTEPBRE as a versatile reference electrode for use at high subcritical and supercritical temperatures.
AB - An operational electrochemical thermocell is proposed for potentiometric pH measurements in high subcritical and supercritical aqueous solutions. The thermocell consists of the silver-silver chloride flow-through external pressure-balanced reference electrode (FTEPBRE) and the flow-through platinum-hydrogen pH sensor. Using this thermocell we have measured the potentials of the thermocell fora few HC1(aq) and NaOH(aq) solutions of different concentrations and derived the corresponding pH differences (ΔpH) over a wide range of temperatures from 25 to 400°C at pressures between 27.5 and 33.8 MPa. Comparison of the experimentally derived and theoretically calculated ΔpH values clearly demonstrates an ability of the thermocell to measure pH with accuracy better than ±0.1 units, and this result in turn demonstrates the viability of the FTEPBRE as a versatile reference electrode for use at high subcritical and supercritical temperatures.
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U2 - 10.1016/s0378-3812(98)00298-2
DO - 10.1016/s0378-3812(98)00298-2
M3 - Conference article
AN - SCOPUS:0032173092
SN - 0378-3812
VL - 150
SP - 515
EP - 523
JO - Fluid Phase Equilibria
JF - Fluid Phase Equilibria
IS - 151
T2 - Proceedings of the 1997 13th Symposium on Thermophysical Properties
Y2 - 22 June 1997 through 27 June 1997
ER -