Selective catalytic oxidation of H2S over iron oxide supported on alumina-intercalated Laponite clay catalysts

Abstract

h i g h l i g h t s• Fe/Al-Lap catalysts with mesoporous structure were synthesized.• Iron oxide mainly exists in form of isolate Fe 3+ in an oxidic environment.• Fe/Al-Lap catalysts show high catalytic activities at low temperature.• The high catalytic activities are ascribed to the interaction between iron oxide and alumina.• The formed Fe 2 (SO 4 ) 3 and elemental sulfur deposits on surface cause catalyst deactivation. g r a p h i c a l a b s t r a c tThe catalytic reaction and deactivation mechanisms for H 2 S selective oxidation over Fe/Al-Lap catalysts are shown in the illustration. The catalytic reaction follows Mars-van Krevelen mechanism. Moreover, the interaction between iron oxide and alumina, the strong acidity of the catalysts and the well dispersion of iron oxide improve the catalytic performance efficiently. Meanwhile, the catalyst deactivation is mainly due to the formation of Fe 2 (SO 4 ) 3 and elemental sulfur deposits on the surface. a r t i c l e i n f o b s t r a c tA series of iron oxide supported on alumina-intercalated clay catalysts (named Fe/Al-Lap catalysts) with mesoporous structure and high specific surface area were prepared. The structural and chemical properties were studied by nitrogen sorption isotherms, X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis DRS), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FTIR), H 2 temperature-programmed reduction (H 2 -TPR) and NH 3 temperature-programmed desorption (NH 3 -TPD) techniques. It was realized that iron oxide mainly existed in the form of isolated Fe 3+ in an oxidic environment. Fe/Al-Lap catalysts showed high catalytic activities in the temperature range of 120-200 • C without the presence of excessive O 2 . This can be attributed to the interaction between iron oxide and alumina, which improve the redox property of Fe 3+ efficiently. In addition, the strong acidity of catalysts and good dispersion of iron oxide were also beneficial to oxidation reaction. Among them, 7% Fe/AlLap catalyst presented the best catalytic performance at 180 • C. Finally, the catalytic and deactivation mechanisms were explored.Crown

Vanadium oxide supported on porous clay heterostructure for the partial oxidation of hydrogen sulphide to sulfur

“…Vanadium oxide based materials constitute an interesting group of catalysts which have been reported recently as potential catalysts for the partial oxidation of H2S to sulfur [5][6][7][8][9][10][11][12][13]. The supported vanadium oxide has been the most studied catalysts.…”

Selective catalytic oxidation of H 2 S to elemental sulfur over titanium based Ti–Fe, Ti–Cr and Ti–Zr catalysts

“…In supported on alumina-intercalated laponite clay catalysts for selective oxidation of H 2 S were reported. The authors emphasized that strong acidity of catalysts was beneficial to the oxidation reaction [14]. XRD patterns of the used TieFe catalysts in the temperature range of 200e300 C were shown in Fig.…”

Modeling and simulation of an improved ammonia-based desulfurization process for Claus tail gas treatment

“…Currently, the Claus process is one of the most important and widely used technologies to recover elemental sulfur from H 2 S-containing gases. 3,4 Nevertheless, the sulfur recovery efficiency is only 90-96% for two-stage Claus reactors and 95-98% for three stage Claus reactors, [5][6][7][8] due to the thermodynamic limitations of the Claus equilibrium reaction. Thus, there are still 2-3% of sulfur compounds (elemental sulfur vapor, COS, CS 2 , SO 2 and H 2 S) le in Claus tail gas.…”