SURFACE POTENTIALS OF AQUEOUS ELECTROLYTE SOLUTIONS

Abstract

The effect of added electrolytes on the surface potential of water was determined using the radioactive electrode technique. Changes in surface potential were found to vary from +64 mV for Na2SO4 at 1.8m to -180 mV for NaCNS at 7.5m. The Group IA chlorides in water gave surface potential differences that decreased in the order K(+) = NH4(+) > Na(+) > Li(+), and the surface potentials of the Group IIA cations decreased in the order Ba(++) > Sr(++) > Mg(++). At a constant anion concentration of 2m the surface potential differences due to the sodium salts were in the order SO4(--) > CO3(--) > CH3COO(-) > Cl(-) > NO3(-) > Br(-) > I(-) > CNS(-). In general the anion with the smaller hydration energy gave the greatest decrease in surface potential. The magnitude of each surface potential change, however, does not appear to be a simple function of the hydration energy or of some related property. The surface potential changes must involve the orientation and structure of the water molecules at the water/air interface, which may be only partially dependent upon the ionic properties as determined in bulk solution.

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Document Details

Document Type
Technical Report
Publication Date
Oct 10, 1967
Accession Number
AD0662656

Entities

People

  • M. A. Scheiman
  • N. L. Jarvis

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Abstracts
  • Agreements
  • Aqueous Solutions
  • Chemical Compounds
  • Chemical Synthesis
  • Chemistry
  • Contamination
  • Electrical Properties
  • Electrolytes
  • Energy
  • Materials
  • Measurement
  • Military Research
  • Organic Materials
  • Surface Properties
  • Surface Tension
  • Water

Fields of Study

  • Chemistry
  • Materials science

Readers

  • Materials Science and Engineering.
  • Mathematics or Statistics
  • Thin Film Deposition Science.