Support features govern the properties of the active phase and the performance of bifunctional ZnFe2O4-based H2S adsorbents

Abstract

Wood-, coal-, and coconut-based activated carbons and ordered mesoporous silica (SBA-15) were selected as supports to synthesize bifunctional ZnFe2O4 adsorbents for an H2S removal from air under ambient conditions. The effects of supports on active phase nanoparticle features and on the efficiency of the H2S removal were investigated. The collected results showed the differences in the composition, morphology and dispersion of the active phase. The carbon supports demonstrated superiority over SBA-15 owing to their electron-rich matrix, abundance of surface defects and the ability to catalyze H2S oxidation. In the case of silica, strong interactions between ZnFe2O4 and SBA-15 leading to the formation of Me–O–Si (Me=Zn, Fe) bonds inactivated metal ions, which was demonstrated in an inferior performance in the H2S removal. The results also indicated that the differences in the graphitization degree, microporosity, and surface pH of the carbon supports result in remarkable differences in the adsorbents efficiency for the H2S removal. This study provides new insights for the rational fabrication of efficient metal oxides-based adsorbents and for a full utilization of their reactive adsorption capability in a nanoscale range.