Spectroscopic Characterization of Molybdenum-Containing Zinc Titanate Desulfurization Sorbents

Molybdenum-containing zinc titanate has been identified as a potential regenerable desulfurization sorbent, removing H[sub 2]S from coal-derived fuel gas up to temperatures of 1,035 K. Sorbents were tested in a laboratory scale fixed bed reactor using simulated coal-derived fuel gas and then removed for analysis. The analyses consisted of X-ray photoelectron spectroscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, and X-ray diffraction. In the sulfided sorbent, migration of zinc to the surface and sulfur in the sulfide form were observed. In the regenerated sorbent, residual sulfur in the sulfate form was observed. In the sulfided and regenerated sorbent after multicycle testing, a small decrease in the Zn/Ti ratio was detected, indicating some zinc migration. The chemical structure of the sulfided sorbent was different from that of the original sample, as observed by Fourier transform infrared spectroscopy.