Influence of surface characteristics on carbon disulfide catalytic hydrolysis over modified lake sediment biochar and research on deactivated mechanism

Abstract

A series of lake sediment biochar (LSB) catalysts modified by metal oxides and basic functional groups were utilized for removal of carbon disulfide (CS2) in yellow phosphorus tail gas. The influences of preparation and modification conditions for surface characteristics of Fe‐KOH/LSB on removal of CS2 were investigated. Surface area and pore structure analyses indicated that preparation processes were aimed to increase the micropore structure of LSB. Diffuse reflection using transform of Fourier infrared radiation results showed that Fe had high hydrolysis activity for CS2 and low oxidation activity for H2S. Thermogravimetric/differential thermal analysis results indicated that low calcination temperature was not conducive to the generation of Fe2O3 and high calcination temperature led to the oxidation of LSB. CO2 temperature programmed desorption results stated that high alkalinity site strength could improve the catalytic hydrolysis performance. High KOH content could enhance alkalinity site strength but led to the block of pore. These modification factors mainly controlled the catalytic hydrolysis ability of Fe‐KOH/LSB. X‐ray photoelectron spectroscopy results claimed that the deactivation of Fe‐KOH/LSB was attributed to the generation of S and sulfate, and the consumption of active component. In the deactivation process, S and sulfate generated and covered the activity sites, and Fe2O3 was converted into FeSO4 or Fe2(SO4)3, which led to the deactivation.