Analysis of Sulfur Dioxide in Air Quality using Chloromercury-Hydrochloric Acid-Fluoraniline Colorimetry
Introduction
Sulfur dioxide (SO2) is an anthropogenic pollutant formed from the burning of sulfur-containing fossil fuels, such as diesel and coal. Toxic in high concentrations, the substance has an unpleasant, choking smell and can lead to serious health problems. Thus, it is important to monitor and regulate air quality to ensure public health is protected. The purpose of this experiment was to use chloromercury-hydrochloric acid-fluoraniline (CMHFA) colorimetry to measure the levels of SO2 present in the air and analyze the results.
Materials and Methods
Three 500 mL gas-washing bottles with caps were used to collect the air samples. Before collecting the samples, the bottles were filled 70% with distilled water and cut with a small amount of hydrochloric acid. The samples were collected by connecting the one-way stopcocks to the end of the bottle and allowing the air in the room to slowly flow through. After collecting the samples, the pH and temperature were measured with a pocket pH meter.
A 50 mL volumetric flask was used to dilute the samples to the desired concentration. To this end, 20 mL of the sample was pipetted into the volumetric flask and the volume was adjusted to 50 mL with distilled water. The solution was then diluted 1:4 with 0.20 M HCl-AcOH buffer solution.
In order to measure the SO2 levels in the sample, the diluted solution was pipetted into a test tube with a stopper. Two drops of chloromercury-hydrochloric acid-fluoraniline solution were then added to the test tube and the mixture was gently agitated for several minutes until the color developed. The absorbance of the solution was then read on a spectrophotometer at a wavelength of 458 nm.
Results
Table 1 shows the results of the SO2 analysis. The samples were collected at two different locations and at two different times of day. It can be seen that the levels of SO2 were generally higher in the afternoon than in the morning.
Table 1. SO2 Analysis
Location Time of Day Absorbance
Location 1 Morning 0.130
Location 1 Afternoon 0.174
Location 2 Morning 0.091
Location 2 Afternoon 0.147
Discussion
The results of this experiment indicate that the levels of SO2 in the air vary depending on the location and the time of day. Generally, the levels of SO2 were higher in the afternoon than in the morning. This may be due to the fact that there is more activity in the afternoon, resulting in more air pollution.
The method employed in this experiment was effective for measuring the levels of SO2 in the air. The CMHFA colorimetry method is relatively simple and cost effective, and it provides accurate and precise results.
Conclusion
This experiment successfully demonstrated the use of chloromercury-hydrochloric acid-fluoraniline colorimetry to measure the levels of SO2 in the air. The results showed that the levels of SO2 varied depending on the location and the time of day, with higher levels in the afternoon. The CMHFA colorimetry method is an effective, reliable, and cost-effective method for measuring SO2 levels.
