In this study, a series of rare earth monosubstituted Dawson-type polyoxometalates were synthesized for highly effective removal of hydrogen sulfide (H 2 S). The unused, used and regenerated polyoxometalates were characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results confirmed that K 17 [Pr(P 2 Mo 17 O 61) 2 ] could maintain a complete Dawson-type structure even after absorption and regeneration. H 2 S absorption study showed that K 17 [Pr(P 2 Mo 17 O 61) 2 ] had the remarkable desulfurization and regeneration capabilities. Optimization experiments showed that K 17 [Pr(P 2 Mo 17 O 61) 2 ] under the condition of low H 2 S concentration or high dosage of K 17 [Pr(P 2 Mo 17 O 61) 2 ] had the ideal desulfurization performance. An appropriate temperature of 25°C is necessary for high removal efficiency. The optimum pH value for desulfurization is 6.8. The desulfurization product was proved to be SO 4 2- .

In this study, a series of transition metal mono-substituted heteropoly compounds H7PMo11MO39 (M=Co 2+ , Mn 2+ , Ni 2+ and Zn 2+ ) (HPMo11M) and single-absent heteropoly compounds H3PMo11O39 (HPMo11) were prepared for highly effective removal of hydrogen sulfide (H2S) from gas stream. The heteropoly compounds were characterized Fourier transform infrared spectroscopy (FT-IR), elemental analysis and scanning electron microscopy (SEM). The results confirmed that the transition metal ions successfully replaced the Mo atom. H7PMo11CoO39 showed that the outstanding desulfurization capacity and the H2S removal efficiency can reach more than 90% for 3 h. Besides, after regeneration, the desulfurization capacity of H7PMo11CoO39 towards H2S only a drop of 5.11% of the initial desulfurization capacity. Optimization experiments demonstrated that H7PMo11CoO39 had the ideal desulfurization performance under the condition of low H2S concentration or high