Role of Pore Structure of Activated Carbon Fibers in the Catalytic Oxidation of H₂S

Abstract

Na2CO3-impregnated activated carbon fibers (ACFs) have been developed as low-concentration H2S oxidation catalysts at ambient temperature. Two series of commercial pitch-based and poly(acrylonitrile)-based ACFs were used to evaluate the role of pore structure in the oxidation of H2S. The initial, impregnated, and exhausted materials were characterized using elemental analysis, N2 adsorption, scanning electron microscopy (SEM), thermogravimetry analysis, and activity tests. The catalytic oxidation of H2S continued until all effective pores of the catalysts were blocked by the oxidation products. The saturation sulfur capacity was found to be in the range of 0.10−0.81 g of H2S/g of catalyst, with the value strongly dependent on the pore structure (especially the volume of pores larger than 0.7 nm) but independent of the nitrogen functional groups. Further quantitative analysis suggested that elemental sulfur as a dominant product mostly deposited in large pores (d > 0.7 nm), whereas sulfuric acid was preferably produced in small micropores (d < 0.7 nm). A possible mechanism of H2S oxidation with respect to the pore size of catalysts is proposed.

Nanocarbons for Catalytic Desulfurization

“…ent temperature. [30] The sulfur saturation capacitiesa re in the range of 0.10 to 0.81 g H 2 S g catalyst À1 ,a nd the values are dependent on the pore structurer ather than the nitrogen functional groups.F or the oxidized products,e lemental sulfur is the main product, and it is mostly formed in large pores (diameter > 0.7 nm), in which Na 2 CO 3 is deposited. Sulfuric acid is preferably formed in the smaller micropores (diameter < 0.7nm) owing to high surface energy and space limitations.…”

“…Ling et al. have introduced alkaline chemicals into activated carbon fibers (ACFs) and have studied their catalytic behavior for the oxidation of low concentrations of H 2 S at ambient temperature . The sulfur saturation capacities are in the range of 0.10 to 0.81 g g catalyst −1 , and the values are dependent on the pore structure rather than the nitrogen functional groups.…”

Application of an Electrochemical NAD+ Recycling System Involving a String-Like Carbon Fiber to an Enzyme Reactor

“…On the other hand, poly(acrylonitrile)-based and pitch-based carbon fibers activated by Na 2 CO 3 -impregnation have very recently been reported to have catalyzing activity for H 2 S oxidation. 15) Therefore, the surface structure of the carbon fiber might have slightly catalyzing activity of oxidation for NADH. In cyclic voltammogram A (Fig.…”

Hydrogen Sulfide (H2S) Removal via MOFs

“…Hydrogen sulfide (H 2 S) is a colorless, corrosive, water-soluble, highly toxic, and flammable acid gas with the characteristic foul odor of rotten eggs, which can be typically found in natural gas, petroleum, and biogas (a byproduct of anaerobic decomposition) [1][2][3][4]. Its separation has significant economic and environmental repercussions for the relevant industries.…”