Sulfur determination in coal using molecular absorption in graphite filter vaporizer

Area of Science:

• Analytical Chemistry
• Spectroscopy

Background:

• Sulfur determination in coal is crucial for environmental monitoring and combustion efficiency.
• Traditional methods for sulfur analysis can be time-consuming and require sample digestion.
• Molecular absorption by sulfur species at high temperatures presents a potential direct analysis avenue.

Purpose of the Study:

• To evaluate the feasibility of direct sulfur determination in coal using molecular absorption spectrometry.
• To compare the effectiveness of platform versus filter furnace atomizers for this analysis.
• To develop and validate a method for accurate sulfur quantification in coal.

Main Methods:

• Analysis of coal slurry using a continuum light source coupled to a low-resolution CCD spectrometer.
• Vaporization of sulfur-containing coal samples in graphite platform and filter furnaces.
• Characterization of molecular absorption spectra in the 200-210 nm range.

Main Results:

• Sulfur modification by carbon during vaporization leads to molecular absorption peaks.
• Platform furnaces exhibit analyte loss and high spectral background, hindering determination.
• Filter furnaces significantly reduce interferences, allowing for accurate sulfur determination.
• Method validated for coals with 0.13-1.5% sulfur content, showing random errors of 5-12%.

Conclusions:

• Direct determination of sulfur in coal via molecular absorption in the 200-210 nm range is viable.
• The filter furnace technique offers superior performance over the platform furnace for this application.
• The developed method provides sensitive and accurate sulfur analysis in coal matrices.