Improved Temperature Stability of Sulfur Dioxide Samples Collected by the Federal Reference Method,

摘要

This report describes an examination of the reagents present in the SO2Federal Reference Method (FRM) to determine if any change in reagent concentration or condition could bring about substantial,if not complete,retardation of the effect of temperature on the stability of collected SO2samples. The parameters initially evaluated were pH, tetrachloromercurate (TCM),and chloride ion concentration. With the development of a modified collecting solution based on these studies (0.04M TCM with a Hg(+2) to Cl(-) of 1/16),collection efficiency and order of reaction of the modified collecting reagent were determined. Using an Arrhenius plot of the experimental data,an equation was derived which describes the relationship between rate of decay of collected SO2samples and temperature. The modified collecting reagent was found to increase the stability of the collected SO2samples over a wider temperature range. Thus the effect of temperature was reduced by about 10C when compared against previous SO2 FRM data. The improvements developed here could be used to liberalize the present temperature specification required to insure the stability of collected SO2samples.