Fluorescence Zn-based metal–organic frameworks for the detection of hydrogen sulfide in natural gas

Abstract

Fluorescent zinc-based metal–organic frameworks (Zn-MOFs) were synthesized via the solvothermal method. The materials were characterized by scanning electron microscopy, Brunauer–Emmett–Teller analysis, X-ray diffraction, Fourier transform infrared spectroscopy, fluorescence spectroscopy and fluorescence photography. The results illustrated that the synthesized Zn-MOFs were highly porous with a maximum surface area of 5755 m² g⁻¹. These MOFs had excellent fluorescence properties, which could be efficiently quenched by trace amounts of hydrogen sulfide (H₂S). The experimental results indicated that Zn-MOFs were responsive to H₂S at the nmol mL⁻¹ level, which is advantageous for fluorescent Zn-MOF-based sensing materials. The synthesized Zn-MOFs also displayed high adsorption abilities toward H₂S. It was illustrated that adsorption played an important role in the preconcentration of H₂S, which can further increase the fluorescence quenching efficiency and improve the sensitivity for H₂S. Under optimized conditions, this Zn-MOF probe exhibited rapid response, excellent selectivity and sensitivity in detection of H₂S. The decrease in FL intensity was linearly related to the H₂S concentration between 0.094 μmol mL⁻¹ and 18 μmol mL⁻¹. The developed strategy was applied to real natural gas well samples. These results indicated that Zn-MOF is a usable functional material for H₂S detection in natural gas, and potentially useful in monitoring natural gas quality and removing H₂S.