Location: Cool and Cold Water Aquaculture ResearchTitle: Adsorption of hydrogen sulfide in biogas using a novel iron-impregnated biochar scrubbing system
|CHOUDHURY, ABHINAV - Freshwater Institute
|LANSING, STEPHANIE - University Of Maryland
Submitted to: Journal of Environmental Chemical Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2020
Publication Date: 11/25/2020
Citation: Choudhury, A., Lansing, S. 2020. Adsorption of hydrogen sulfide in biogas using a novel iron-impregnated biochar scrubbing system. Journal of Environmental Chemical Engineering. 9:104837. https://doi.org/10.1016/j.jece.2020.104837.
Interpretive Summary: Hydrogen sulfide is a biogas impurity produced from anaerobic digestion of organic matter, which can corrode piping and energy generation systems. Adsorbents with high surface areas, such as biochar or activated carbon, can be used to capture hydrogen sulfide from biogas in a gas filtering system. The primary objective of this research was to enhance the hydrogen sulfide adsorption effectiveness of biochar by dispersing iron particles on the biochar surface. The iron containing biochar resulted in up to 3.9 times increase in hydrogen sulfide capture from biogas. Iron containing biochar may be a low-cost, high efficiency alternative to activated carbon for hydrogen sulfide capture from biogas.
Technical Abstract: Two biochar substrates, corn stover biochar (CSB) and maple wood biochar (MB), with and without Fe-impregnation were evaluated for H2S adsorption from biogas. The H2S adsorption capacity was quantified using dynamic breakthrough experiments. Iron-impregnated maple biochar (MB-Fe) had the highest H2S saturation adsorption capacity (23.9 mg H2S/g biochar), which was 3.9 times higher than the unmodified MB (6.1 mg H2S/g biochar). The Fe-impregnated corn stover biochar (CSB-Fe) saturation H2S sorption capacity (8.2 mg H2S/g biochar) was 2.5 times higher than the unmodified CSB (3.3 mg H2S/g biochar). The presence of iron oxide (Fe3O4) was observed through X-ray diffraction and scanning electron microscopy in the Fe-impregnated biochar substrates, with ferrous sulfate (FeSO4) as one of the end products in the saturated biochar surface and elemental sulfur in the pores. The study showed how Fe-impregnation can result in a multifold increase in H2S adsorption from biogas compared to unmodified biochar.