Carbon Nanofilaments Functionalized with Iron Oxide Nanoparticles for in-Depth Hydrogen Sulfide Adsorption

Abstract

The purification of hydrogen prior of its use in various applications, such as fuel cells, is of paramount importance. Although there are many commercial ways to obtain hydrogen sulfide, the need to reach very low concentration values, at the ppm or even at the ppb level, is the main motivation behind this work. This work examines the production and utilization of a new, low H 2 S breakthrough and high capacity adsorbent, made of iron nanoparticles embedded in carbon nanofilaments. It is produced by a 2-step functionalization methodology: acid pretreatment and iron wet impregnation. This novel adsorbent was characterized by scanning transmission electron microscope, X-ray absorption near edge structure, Brunauer Emmet and Teller calculations, and thermogravimetric analysis, and the adsorption efficiency was measured for different iron-loadings, temperatures, and H 2 S breakthrough values. Operating conditions and metal-loading that allow a decrease of H 2 S concentration from 500 ppm to below 1.5 ppm are reported. It has also been found that acid treatment influences metal dispersion and, due to the nanometric nature of adsorbents, the process is not controlled by mass diffusion phenomena.

Biogas Cleaning: Activated Carbon Regeneration for H2S Removal

“…The adsorption capacity without oxygen in the biogas is slightly higher than the reference values at an operating temperature of 100 • C and breakthrough concentration of 1 ppm(v) [41,42]. Considering that the operating temperature selected was around 20 • C, this carbon has better H 2 S adsorption performance than results from literature [41].…”

“…Considering that the operating temperature selected was around 20 • C, this carbon has better H 2 S adsorption performance than results from literature [41].…”

“…at an operating temperature of 100 °C and breakthrough concentration of 1 ppm(v) [41,42]. This model was elaborated for SMAT conditions, but it could be applied to any inlet H 2 S concentration or biogas speed, even if less strictly, with similar trends (results unpublished).…”

Experimental methods in chemical engineering: Transmission electron microscopy—TEM

“…R&D research exploits TEM‐related techniques for several classes of materials relevant to the chemical engineering, including metals, ceramics (oxides, carbides, and nitrides,) polymer, and composites materials . TEM is common for probing carbon nanostructures such as nanotubes, nanofilaments, nanohorns, and graphene…”

Study on the Structure and Morphology of Iron Nanopowders Obtained by the Method of Electric Explosion of Wires

“…The iron nanoparticles have great potential for various applications, including their use as catalysts for formation of carbon nanofibers and nanotubes [1][2][3], contrast agents for magnetic resonance imaging [4], fillers of iron-nickel battery [5] and as adsorbents and catalysts for purification of exhaust gases [6]. Different sizes of iron nanoparticles are required depending on the application.…”