Method for assessing the inertia of carbon dioxide gas exchange across the water-air interface

The article considers changes in water properties under the influence of various external factors and points out the absence of a generally accepted technique for accounting for the effect of air on distilled water. The possibility of instrumental assessment of the effect of carbon dioxide CO2 on the electrical conductivity of distilled water is analyzed. For this purpose, the inertia of CO2 gas exchange at the water/air interface in sealed conductometric cells with a degree of filling with distilled water within 10–100 % and water heating (cooling) rates of 0.04–2.00 °C·min–1 was experimentally studied. A method for numerical assessment of the inertia of CO2 gas exchange at the water/air interface using a special coefficient of gas exchange inertia is proposed. This coefficient is calculated based on the ratio of the change in the specific electrical conductivity of water to the average value of this parameter in the “heating – cooling” mode. When measuring the electrical conductivity of water, its temperature varied within 20–55 °C. Based on the results of the experiments, the dependences of the gas exchange inertia coefficient on the water heating rate at different cell filling factors were obtained. It was shown that the gas exchange inertia is maximum at the maximum water heating (cooling) rate and minimum cell filling with water. The highest value of the CO2 gas exchange inertia coefficient in the experiments was about 8 %. The results obtained can be used in practice for quantitative assessment of the permeability of the water/air interface for CO2 molecules under various external influences on water.

water/air interface, gas exchange inertia, water conductivity, carbon dioxide