Hydrogen Sulfide (H2S) Removal via MOFs

In the work presented herein, a joint experimental and theoretical approach has been carried out to obtain an insight into the desulfurization performance of an industrial molecular sieve (IMS), resembling a zeolitic structure with a morphology of cubic crystallites and a high surface area of 590 m 2 g –1 , with a view to removing H 2 S from biogas. The impact of temperature, H 2 S inlet concentration, gas matrix, and regeneration cycles on the desulfurization performance of the IMS was thoroughly probed. The adsorption equilibrium, sorption kinetics, and thermodynamics were also examined. Experimental results showed that the relationship between H 2 S uptake and temperature increase was inversely proportional. Higher H 2 S initial concentrations led to lower breakpoints. The presence of CO 2 negatively affected the desulfurization performance. The IMS was fully regenerated after 15 adsorption/desorption cycles. Theoretical studies revealed that the Langmuir isotherm better described the sorption behavior, pore diffusion was the controlling step of the process (Bangham model), and that the activation energy was 42.7 kJ mol –1 (physisorption). Finally, the thermodynamic studies confirmed that physisorption predominated.

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“…However, in most cases, they need energetically demanding regeneration processes (typically above 450 °C). 17 …”

Section: Introductionmentioning

confidence: 99%

Adsorption of Hydrogen Sulfide at Low Temperatures Using an Industrial Molecular Sieve: An Experimental and Theoretical Study

et al. 2021

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“…Such numbers are comparable with the literature data of CO 2 adsorption by 1b ′ (122 cm 3 ·g −1 at 273 K, 46 cm 3 ·g −1 at 298 K). Taking into account the crystallographic densities, the corresponding volumetric uptakes for 1se ′ were calculated to be 116 cm 3 ·cm −3 (273 K) and 48.5 cm 3 ·cm −3 (298 K), which exceeds those for 1b ′ by 15% (101 cm 3 ·cm −3 ) at 273 K (see Figure 4 ) and by 28% (38 cm 3 ·cm −3 ) at 298 K, respectively, convincingly confirming a positive effect of the polarizable heteroatom (Se) on the absorption properties of porous materials [ 38 , 39 , 40 , 41 ]. Similarly, the isosteric heat of CO 2 adsorption at zero coverage Q st (0) for 1se ′ (19.9 kJ·mol −1 ) is greater than for 1b ′ (19.0 kJ·mol −1 ), indicating stronger binding of CO 2 with the porous framework containing the selenophene heterocycle.…”

Section: Resultsmentioning

confidence: 69%

A Selenophene-Incorporated Metal–Organic Framework for Enhanced CO2 Uptake and Adsorption Selectivity

et al. 2020

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A new metal–organic coordination polymer [Zn2(sedc)2(dabco)] (1se; sedc2− = selepophene-2,5-dicarboxylate; dabco = 1,4-diazabicyclo[2.2.2]octane) was synthesized and characterized by single-crystal X-ray diffraction analysis. This MOF is based on {Zn2(OOCR)4N2} paddle wheels and is isoreticular to the family of [Zn2(bdc)2(dabco)] derivatives (1b; bdc2− = 1,4-benzenedicarboxylate) with pcu topology. The gas adsorption measurements revealed that 1se shows a 15% higher CO2 volumetric uptake at 273 K and 28% higher CO2 uptake at 298 K (both at 1 bar) compared to the prototypic framework 1b. Methane and nitrogen adsorption at 273 K was also investigated, and IAST calculations demonstrated a pronounced increase in CO2/CH4 and CO2/N2 selectivity for 1se, compared with 1b. For example, the selectivity factor for the equimolar CO2/CH4 gas mixture at 1 bar = 15.1 for 1se and 11.9 for 1b. The obtained results show a remarkable effect of the presence of selenium atom on the carbon dioxide affinity in the isoreticular metal–organic frameworks with very similar geometry and porosity.

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“…Generally, a variety of physicochemical methods have been applied for the removal of the H 2 S generated from industrial processes such as petroleum refining, natural gases, biogas processing and coal gasification [170][171][172]. Compared to naphtha which contains about 1.5% sulfur, bio-oil derived from the fast pyrolysis of biomass has a sulfur content in the range of 0.01-0.2% [142].…”

Section: Sulfur Poisoningmentioning

confidence: 99%

Recent Progress in the Steam Reforming of Bio-Oil for Hydrogen Production: A Review of Operating Parameters, Catalytic Systems and Technological Innovations

et al. 2021

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The present review focuses on the production of renewable hydrogen through the catalytic steam reforming of bio-oil, the liquid product of the fast pyrolysis of biomass. Although in theory the process is capable of producing high yields of hydrogen, in practice, certain technological issues require radical improvements before its commercialization. Herein, we illustrate the fundamental knowledge behind the technology of the steam reforming of bio-oil and critically discuss the major factors influencing the reforming process such as the feedstock composition, the reactor design, the reaction temperature and pressure, the steam to carbon ratio and the hour space velocity. We also emphasize the latest research for the best suited reforming catalysts among the specific groups of noble metal, transition metal, bimetallic and perovskite type catalysts. The effect of the catalyst preparation method and the technological obstacle of catalytic deactivation due to coke deposition, metal sintering, metal oxidation and sulfur poisoning are addressed. Finally, various novel modified steam reforming techniques which are under development are discussed, such as the in-line two-stage pyrolysis and steam reforming, the sorption enhanced steam reforming (SESR) and the chemical looping steam reforming (CLSR). Moreover, we argue that while the majority of research studies examine hydrogen generation using different model compounds, much work must be done to optimally treat the raw or aqueous bio-oil mixtures for efficient practical use. Moreover, further research is also required on the reaction mechanisms and kinetics of the process, as these have not yet been fully understood.

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Hydrogen Sulfide (H2S) Removal via MOFs

Cited by 52 publications

References 129 publications

Adsorption of Hydrogen Sulfide at Low Temperatures Using an Industrial Molecular Sieve: An Experimental and Theoretical Study

Adsorption of Hydrogen Sulfide at Low Temperatures Using an Industrial Molecular Sieve: An Experimental and Theoretical Study

A Selenophene-Incorporated Metal–Organic Framework for Enhanced CO2 Uptake and Adsorption Selectivity

Recent Progress in the Steam Reforming of Bio-Oil for Hydrogen Production: A Review of Operating Parameters, Catalytic Systems and Technological Innovations

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