1 research outputs found
Role of Surface Chemistry and Morphology in the Reactive Adsorption of H<sub>2</sub>S on Iron (Hydr)Oxide/Graphite Oxide Composites
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 H<sub>2</sub>S 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 H<sub>2</sub>S due to the incorporation of OH reactive groups and
an increase in surface heterogeneity