An experimental investigation of the surface tension of seawater

Abstract

Surface tension of seawater was measured for absolute salinities S = (20.01, 35.18, 40.49, 79.39, 121.54) g/kg across a temperature range of T = (0 - 90)°C at atmospheric pressure using the Wilhelmy plate method. The uncertainty within measurements varied between 0.04 - 0.33 mN/m with the average uncertainty being 0.12 mN/m. The experimental procedures were validated with tests conducted on ACS reagent grade water and aqueous sodium chloride solutions. A best fit correlation was developed expressing surface tension of seawater as a function of temperature and salinity. The average absolute deviation between measurements and the correlation was 0.19% while the maximum deviation was 0.60%. The surface tension of seawater was found to be comparable to within 1.37% of the surface tension of aqueous sodium chloride. The surface tension of 0.2 [mu]m microfiltered and ultraviolet radiation treated natural seawater was found to be similar to that of laboratory prepared seawater.