Rapid determination of sulfide sulfur in anaerobic system by gas-phase molecular absorption spectrometry

Abstract

Sulfide sulfur, an important indicator for environmental monitoring and anaerobic bioengineering, has attracted increasing attention because of its significance in the anaerobic biotreatment processes and its high toxicity to humans and aquatic microorganisms. A detection system was designed for rapid and accurate determination of sulfide sulfur in an anaerobic system by gas-phase molecular absorption spectrometry (GPMAS). On the basis of the maximum absorption of hydrogen sulfide (H₂S) at 202.6 nm, the calibration curve between sulfide content and absorbance was obtained, and then used to calculate the sulfide concentration in samples. The simulated samples of landfill leachate were used for detection after the anaerobic reaction. A new method for the removal of the effects of interference ions on the determination of sulfide in the fermentation broth is proposed. The results showed that the method obtained satisfactory precision and recovery. The detection limit of H₂S in biogas is 5.1 × 10⁻³ mg L⁻¹, the quantification limit is 1.7 × 10⁻² mg L⁻¹; in fermentation broth the detection limit of S²⁻ is 1.2 × 10⁻² mg L⁻¹, the quantification limit is 4.1 × 10⁻² mg L⁻¹; the detection limit of acid volatile sulfide (AVS) in the fermentation residue is 2.7 × 10⁻² mg g⁻¹ (dry sample) and the quantification limit is 8.9 × 10⁻² mg g⁻¹ (dry sample). This indicates that the proposed method is suitable for the determination of sulfide sulfur derived from anaerobic systems.