Role of Surface Chemistry and Morphology in the Reactive Adsorption of H₂S on Iron (Hydr)Oxide/Graphite Oxide Composites

Abstract

Composites of magnetite and two-line ferrihydrite with graphite oxide (GO) were synthesized and tested as hydrogen sulfide adsorbents. Exhausted and initial composites were characterized by the adsorption of nitrogen, X-ray diffraction, potentiometric titration, thermal analysis, and FTIR. The addition of GO increased the surface area of the composites due to the formation of new micropores. The extent of the increase depended on the nature of the iron (hydr)oxide and the content of GO. The addition of GO did not considerably change the crystal structure but increased the number of acidic functional groups. While for the magnetite composites an increase in the H2S adsorption capacity after GO addition was found, the opposite effect was recorded for the ferrihydrite composites. That increase in the adsorption capacity was linked to the affinity of the composites to adsorb water in mesopores of specific sizes in which the reaction with basic surface groups takes place. Elemental sulfur and ferric and ferrous sulfates were detected on the surface of the exhausted samples. A redox reactive adsorption mechanism is proposed to govern the retention of hydrogen sulfide on the surface of the composites. The incorporation of GO enhances the chemical retention of H2S due to the incorporation of OH reactive groups and an increase in surface heterogeneity.

Environmental implications and applications of engineered nanoscale magnetite and its hybrid nanocomposites: A review of recent literature

“…Although the preferential oxidation of CO in H2-rich stream is used in the production of clean H2 for H2-based fuel cells, this catalyst can be used for CO removal from contaminated air [214]. Composites of magnetite and two-line ferrihydrite with GO have been tested as H2S adsorbents ( Figure 12) [215]. The addition of GO increases the surface area of the composites due to the formation of new micropores, leading to an increase in the H2S adsorption capacity; the opposite effect is recorded for the ferrihydrite composites [215].…”

“…Composites of magnetite and two-line ferrihydrite with GO have been tested as H2S adsorbents ( Figure 12) [215]. The addition of GO increases the surface area of the composites due to the formation of new micropores, leading to an increase in the H2S adsorption capacity; the opposite effect is recorded for the ferrihydrite composites [215]. Magnetic TiO2@SiO2@Fe3O4 and Cu/TiO2@SiO2@Fe3O4 photocatalysts show good catalytic activity in the CO2 reduction reaction to produce methanol and the addition of Cu improves the productivity [216].…”

Efficient Air Desulfurization Catalysts Derived from Pig Manure Liquefaction Char

“…Since the samples were synthesized at 900 • C, all changes observed at temperatures below that should be linked to H 2 S exposure. For the exhausted AB and AB-NG, the new weight loss appears at 200, 400 and about 600 • C. Based on the history of the samples, the decomposition temperature and the results published in the literature [45,49], we assign those peaks to the removal of sulfuric acid, elemental sulfur and SO 3 from the decomposition of iron sulfate, respectively [50]. The peak related to the removal of elemental sulfur from BA at 400 • C is very sharp, which indicates the deposition of a rather small amount of sulfur on the external surface of this low porosity sample.…”

Highly esthetic, deodorant, and antibacterial tile with natural zeolite set via a blast furnace slag-based geopolymer

“…This was probably due to high alkalinity of the tile surface, so that H 32) iron oxide/graphite (114 mg H 2 S•g ¹1 ). 33) Nonetheless, the tiles developed in this study may be enough applied to interior building products providing us with comfortable lifestyle.…”