Improving the Method for Measuring Bromine Compounds in Flue Gas

The method detection limit (MDL) using UV-VIS spectrometry (UV/VIS) is the primary method to detect bromine compounds in the flue gas. However, the level of bromine compounds in the flue gas is 0.6 ppm, reaching 20% of the emission limit of 3.0 ppm, which limits the analysis of low-concentration samples. As per the United States Environmental Protection Agency and official test standards for water pollution, bromine compound analysis was performed using ion chromatography (IC). Hydrogen chloride was analyzed using IC, referencing official test standards for air pollution. Therefore, 0.1 M NaOH and distilled water (D.W.) were applied to the absorption solution of the IC analysis sample. Validation was conducted for IC (D.W.), IC (0.1 M NaOH), and UV/VIS (0.1 M NaOH) to improve the analysis method for bromine compounds in the flue gas. The linearity (R2) of the calibration curve for IC (D.W.) satisfied the R2 (0.98 or more) value calculated in the UV/VIS of the official test standards for air pollution. However, the R2 of UV/VIS (0.1 M NaOH) and IC (0.1 M NaOH) was not satisfied. In IC (D.W.) analysis results, the average values of MDL, MLQ (minimum level of quantification), accuracy and precision were 0.127 ppm, 0.403 ppm, 3.7%, and 102.9%, respectively. MDL and MLQ showed the lowest concentration compared to the other two methods, and had high accuracy and precision. Regarding the recovery rate by the absorbing liquid, IC (D.W.) was the highest at 93.55%, followed by UV/VIS (0.1 M NaOH) and IC (0.1 M NaOH). This study analyzed bromine compounds in flue gas with higher accuracy and precision using the IC (D.W.) method compared to IC (0.1 M NaOH) and UV/VIS (0.1 M NaOH).