Low BET Research Articles

Clay reinforced polyimide/silica hybrid aerogel

Silica aerogels are comprised of highly porous three-dimensional networks. They typically are very fragile and brittle due to the inter-particle connections in the pearl-necklace-like fractal network. This behavior prevents their wider utility. The present study aims to reinforce the silica-based gel to improve the poor mechanical strength through crosslinking the silica particles with polyimide and incorporating Lucentite STN clay into the skeletal silica–polyimide network. 3-Aminopropyltriethoxysilane (APTES) end-capped polyamic acid oligomers were first formed followed by gelation with TMOS at a range of clay concentrations to generate a silica network. The incorporation of clay leads to slightly lower BET surface area with little effect on shrinkage, porosity and density. Microscopy revealed that the aerogel preferentially grows from the edges of well dispersed clay particles while minimal growth occurs from clay surfaces. The formation of covalent bonds and hydrogen bonding through the OH functionalized clay edges is thought to enhance the connectivity with silica network and clay, leading to a substantial reinforcement effect as evidenced by an increase in modulus.

Quantitative Studies on the Oxygen and Nitrogen Functionalization of Carbon Nanotubes Performed in the Gas Phase

Gas-phase methods were applied for the oxygen and nitrogen functionalization of multiwalled carbon nanotubes (CNTs). The oxygen functionalization was performed by HNO3 vapor treatment at temperatures from 200 to 250 °C for 12 h up to 120 h. The oxygen-functionalized CNTs were used as the starting material for nitrogen functionalization through thermal treatment under NH3. The BET surface area increased after the treatment in HNO3 vapor, which also caused the weight loss due to carbon corrosion. The oxygen content increased with increasing treatment time but decreased with increasing temperature, as disclosed by elemental analysis, X-ray photoelectron spectroscopy, and temperature-programmed desorption (TPD) results. The surface acidity increased with increasing treatment time as shown by TPD using NH3 as a probe molecule. As to nitrogen functionalization, the amount of nitrogen was correlated with the oxygen amount in the starting CNTs. A higher NH3 concentration caused a lower BET surface area due to carbon corrosion. The incorporation of both oxygen and nitrogen lowered the thermal resistance of CNTs. The nitrogen-functionalized CNTs showed only a slight decrease, in contrast to a significant decrease observed for O-functionalized CNTs. The formation or removal of coordinatively unsaturated carbon like amorphous carbon or defects was found to be involved in all of the functionalization, desorption, and oxidation processes.

Swelling of MCM-56 and MCM-22P with a new medium — surfactant–tetramethylammonium hydroxide mixtures

Two different types of layered MWW zeolite, i.e., delaminated MCM-56 and multilayer MCM-22P, have been studied for swelling using a new surfactant/tetraalkylammonium combination as the swelling reagent. The commonly used in the past tetrapropylammonium hydroxide (TPA-OH) was replaced by its tetramethylammonium (TMA-OH) homologue. The latter was previously considered unsuitable for use in swelling of MCM-22P. The extent of swelling with different amounts of TMA-OH accompanying surfactant was determined first by X-ray diffraction. Selected samples were pillared with silica and evaluated quantitatively by nitrogen sorption at 77K and FTIR. The swelling of MCM-56, which is reported in detail for the first time, has been found to be more facile and extensive compared to the multi-layer MCM-22P, consistent with its delaminated nature. BET surface areas of pillared MCM-56 samples increase with the amount of hydroxide used for swelling and approach 700m2/g. Pillared MCM-22P show similar trend but have somewhat lower BET values than pillared MCM-56. The observed successful swelling of MCM-22P is notable because the presence of small cations was previously found to be unfavorable for this process. FTIR measurements of selected samples confirmed higher Al/acid center content in pillared MCM-56 products in comparison to MCM-22 ones. Compared to unmodified MCM-22, there was an increase in most cases in the concentration of acid sites interacting with di-tert-butyl-pyridine. This confirms increased access of larger molecules to acid sites, which is the main goal of such swelling/pillaring treatments.

Analysis of Estrogen Receptors Alpha Versus Beta in the Uterine Endothelial Cell Plasma Membrane and Their Interaction with Cav-1 for eNOS Activation.

Uterine endothelial nitric oxide (NO) production is partly responsible for the maintenance of vasodilatation during physiologic states of high circulating estrogen levels such as pregnancy. Estrogen receptors (ER-a and/or ER-β) are classically thought of as nuclear transcription factor receptors; however, a small pool (3-5%) of ERs is localized to the plasma membrane of endothelial cells that are responsible for nongenomic vasodilatory responses. We and others have previously shown that ERs induce very rapid activation of ERK signaling and eNOS to increase NO production. In addition, these rapid changes were observed with estradiol-17β bound to plasma membrane impermeable BSA and the NO responses were ER-mediated since they were blocked by ICI, 182,780. Various estrogenic effects have been shown to be mediated by one or both ERs and may be dependent on interactions with Cav-1, the main caveolae scaffolding protein. It is unclear whether rapid NO productions are mediated by plasma membrane Cav-1 associated ER-a and/or ER-β. We hypothesize that ER-a and ER-β maintain similar spatial partitioning between the plasma membrane and nucleus of Uterine Artery Endothelial Cell (UAECs), similar interactions with Cav-1 protein at the plasma membrane, and are capable of changing the eNOS phosphorylation patterns indicative of temporal and special NO activation state. UAECs lysates were subjected to Immunoisolation column chromatography using Cav-1 antibody to identify protein-protein interactions between Cav-1 and ER-a or ER-β. Transmission Electron Microscopy (TEM) was employ to visualized caveolae structures at the plasma membrane of UAECs under control and estrogen treatment. TEM ImmunoGold label visualization was employed to localize ER-a and ER-β at the UAEC plasma membrane and within the caveolae structures. Lastly, UAECs were treated with control or increasing concentrations of estradiol-17β (0.1-100nM) and changes in eNOS stimulatory phosphorylation sites, Ser 1177, Ser 635 vs. inhibitory site Thr 495 were evaluated via Western blot analyzes. UAEC protein Cav-1 immunoisolation columns showed that ER-a was tightly bound to Cav-1. In contrast, Cav-1 did not appear to interact with ER-β with high affinity. TEM revealed that UAECs have substantial numbers of caveolae structures on the plasma membrane. Immunogold labeling revealed that ER-a has relatively low expression bet very discrete focal caveolar allocations within the UAEC plasma membrane. However, ER-β showed a much higher expression patterns throughout the cell but similar focal patterns as ER-a at the plasma membrane. Increasing estradiol-17β concentrations directly increased stimulatory Ser 1177, Ser 635 phosphorylation with a concurrent decrease in inhibitory Thr 495 phosphorylation in eNOS, indicating elevations in eNOS activation. These data support the hypothesis that plasma membrane ERs mediate NO production through the activation of signaling cascades that alter eNOS multi-site phosphorylation state, protein-protein interactions with Cav-1, and its temporal spatial distribution. NIH GM083252, HL49210, HD38843, HL87144, AA19446.

Preparation and in situ spectroscopic characterization of Cu-clinoptilolite catalysts for the oxidative carbonylation of methanol

Cu-containing natural and synthetic clinoptilolite were prepared by Cu cation exchange and impregnation with copper nitrate solution. The samples were characterized and tested for the synthesis of dimethyl carbonate. The state of Cu(I) and Cu(II) species was proved by in situ FTIR spectroscopy using CO and NO as probe molecules. The observed bands of νCu(I)–CO and νCu(II)–NO modes are relatively broad indicating a location of the Cu cations at several sites in the zeolite lattice. Cu-clinoptilolite catalysts oxidize CO and NO to a certain extent even at room temperature where CO2 is partly captured in the zeolite cavities.The interaction of the catalysts with MeOH/CO/O2 gas mixtures was studied by in situ FTIR spectroscopy and operando DRIFTS/MS. Oxygenated products like dimethoxy methane and methyl formate were found besides CO2 in the gas phase while formate, methyl formate and methoxy species were adsorbed at the catalyst surface. In contrast to Cu-Y catalysts no dimethyl carbonate formation could be detected. Obviously, the different channel system of clinoptilolite and the distinct lower BET surface area are disadvantageous concerning dimethyl carbonate formation.

Crystallographically mapped ligand binding differs in high and low IgE binding isoforms of birch pollen allergen bet v 1.

The ability of pathogenesis-related proteins of family 10 to bind a broad spectrum of ligands is considered to play a key role for their physiological and pathological functions. In particular, Bet v 1, an archetypical allergen from birch pollen, is described as a highly promiscuous ligand acceptor. However, the detailed recognition mechanisms, including specificity factors discriminating binding properties of naturally occurring Bet v 1 variants, are poorly understood.Here, we report crystal structures of Bet v 1 variants in complex with an array of ligands at a resolution of up to 1.2 Å. Residue 30 within the hydrophobic pocket not only discriminates in high and low IgE binding Bet v 1 isoforms but also induces a drastic change in the binding mode of the model ligand deoxycholate. Ternary crystal structure complexes of Bet v 1 with several ligands together with the fluorogenic reporter 1-anilino-8-naphthalene sulfonate explain anomalous fluorescence binding curves obtained from 1-anilino-8-naphthalene sulfonate displacement assays. The structures reveal key interaction residues such as Tyr83 and rationalize both the binding specificity and promiscuity of the so-called hydrophobic pocket in Bet v 1.The intermolecular interactions of Bet v 1 reveal an unexpected complexity that will be indispensable to fully understand its roles within the physiological and allergenic context.

Pilot Plant Scale Synthesis of CNS: Influence of the Operating Conditions

The present work was an in-depth study related to synthesis of carbon nanospheres (CNSs) at different scales (lab and pilot) with the end goal to economize the production of these materials on a large scale. Synthesis of large amounts of CNSs relies on the careful control of the operating conditions such as space velocity (helium flow rate), hydrocarbon (benzene) content in feed stream, and synthesis time. The alteration of these variables caused important changes in both the yield and properties of the obtained materials. In general, characterization results of the synthesized CNSs demonstrated that they showed low BET surface area and pore volume values typical of spherical geometrical bodies, good thermal stability, and good crystallinity. Normally, CNSs are presented as conglomerates as consequence of the accretion via the carbon atoms at the edge of the “curling” graphitic flakes. Finally, results demonstrated a successful scale up, obtaining a CNSs yield at pilot scale considerably superior (factor of 3.9) to that obtained at laboratory scale.

Improvement of cetane number of LGO by ring opening of naphthenes on Pt/Al-SBA-15 catalysts

Al-SBA-15 with high surface area and avg. pore diameter was prepared using hydrothermal synthesis. Platinum (0–1.75wt.%) was incorporated in the Al-SBA-15 support and the catalytic activity was tested using hydrotreated light gas oil (HLGO) as the feed. All the catalysts were thoroughly characterized using N2 adsorption, ICP, TPD, SAX, FTIR, NMR and TEM analysis. Most of the Al in the support was in the framework with tetrahedral coordination (27Al NMR) and the prevalence of the hexagonal mesoporous structure with Pt doping was confirmed from the low angle SAX, BET and TEM study. The incorporation of Al in the framework and the corresponding acidity improvement were confirmed from the TPD and Pyridine FTIR (Py-FTIR) analysis. The dispersion of the Pt was improved until 1.5% Pt incorporation, beyond which the Pt clusters were formed. Screening of the catalysts was carried out in a Parr autoclave and observed that 1.5%Pt/Al-SBA-15 is an effective catalyst for improvement in cetane index of HLGO. These activity results are in correlation with the dispersion of the Pt on Al-SBA-15. More than 90% of aromatic conversions were observed on 1.5%Pt/Al-SBA-15. A maximum cetane index of 64 was observed on 1.5%Pt/Al-SBA-15 at 350°C, whereas reference (Pt/HY) catalyst could not improve the cetane index mainly due to the formation of secondary cracking products.

The effect of microstructure on air oxidation resistance of nuclear graphite

Oxidation resistance in air of three grades of nuclear graphite with different structures was compared using a standard thermogravimetric method. Differences in the oxidation behavior have been identified with respect to both (i) the rate of oxidation in identical conditions and the derived apparent activation energy and pre-exponential factor and (ii) the penetration depth of the oxidant and the development of the oxidized layer. These differences were ascribed to structural differences between the three graphite grades, in particular the grain size and shape of the graphite filler, and the associated textural properties, such as total BET surface area and porosity distribution in the un-oxidized material. It was also found that the amount of strongly bonded surface oxygen complexes measured by thermodesorption significantly exceeds the amount afforded by the low BET surface area, and therefore low temperature oxygen chemisorption is not a reliable method for determining the amount of surface sites (re)active during air oxidation. The relationship between nuclear graphite microstructure and its oxidation resistance demonstrated in this work underlines the importance of performing comprehensive oxidation characterization studies of the new grades of nuclear graphite considered as candidates for very high temperature gas-cooled reactors.

Synthesis, characterisation and adsorption properties of a porous copper(ii) 3D coordination polymer exhibiting strong binding enthalpy and adsorption capacity for carbon dioxide

The synthesis and characterisation of microporous coordination polymers containing copper(II) or cobalt(II) and 2-(pyridin-4-yl)malonaldehyde (Hpma) is described and the gas adsorption properties evaluated. Single-crystal X-ray structure determinations identified the structures as [M(pma)(2)]·2X (M = Cu, 1; Co, 2; X = MeOH, MeCN), which contain 3D networks with rutile topology and continuous 1D rectangular channels with diameters ranging from 3 to 4 Å. The materials exhibit low BET surface areas of 143 m(2) g(-1), but possess large capacities for carbon dioxide capture of 14.1 wt%. The small pore channels are shown to account for this, delivering a particularly strong binding enthalpy to adsorbed CO(2) of 38 kJ mol(-1), and a very large adsorption capacity relative to the low surface area.

Catalytic oxidation of toluene and p-xylene using gold supported on Co 3O 4 catalyst prepared by colloidal precipitation method

Gold supported on cobalt oxide has been successfully synthesized through a colloidal precipitation method and tested in toluene and p-xylene total oxidation. It has been demonstrated that the catalytic activity of Au/Co 3O 4 for toluene and p-xylene oxidation is much higher than that of Au/Al 2O 3 and Au/MgO in spite of its lower BET surface area and larger gold crystalline size. The enhanced catalytic activity in toluene and p-xylene oxidation has been linked to a high concentration of superficial electrophilic oxygen species and oxygen vacancies, which may be originated from a strong interaction in the colloidal Au–Co 3O 4 system.

Activated carbons from sewage sludge: Application to aqueous-phase adsorption of 4-chlorophenol

Activated carbons of different characteristics have been prepared from dried sewage sludge using CO 2, air and KOH as activating agents. The adsorption capacity of the resulting materials has been checked using 4-chlorophenol as a target compound in aqueous solution. CO 2 and air-activation led to carbons of low BET area which increased with the activation temperature but did not reach 100 m 2/g at the best. The high ash content of the starting material (23%, d.b.) limits the development of porosity since the partial gasification does not affect the inorganic matter. In the case of air-activation, the resulting surface remains fairly low even in ash-free basis, reaching no more than 250 m 2/g. Activation with KOH allows a much higher development of porosity. Using a KOH to solids ratio of 3:1 and a temperature of 750 °C a BET area above 1800 m 2/g with a mesopore volume higher than 0.35 cm 3/g was reached. In spite of those dramatic differences on the textural properties, the air-activated carbons showed an adsorption capacity for 4-chlorophenol of almost 85% that of the KOH-activated carbons. These results warrant in principle air-activation at moderate temperature as a promising way of sewage sludge valorisation to inexpensive adsorbents for the removal of water pollutants.

Synthesis of higher surface area mayenite by hydrothermal method

Mayenite (Ca 12Al 14O 33) is an important material, being used as a transparent conductive oxide (TCO), catalysts for VOCs cleaning and ionic conductor. Unfortunately, the material has a very low BET surface area, generally below 10 m 2/g and requires higher calcination temperature for the formation of mayenite phase. In this study, a new synthesis method, namely hydrothermal method, was employed for the synthesis of mayenite with higher BET surface area of about 70 m 2/g, and also the calcination temperature decreased from over 1000 to just 400 °C. It was found that mayenite from different method shows different shapes.

Three-component commitment and turnover: An examination of temporal aspects

SEM ( N = 182) was employed to examine implied temporal aspects of three-component commitment theory as they relate to turnover. Consistent with expectations, affective commitment predicted subsequent turnover in an immediate and relatively short interval of 4 months, but failed to do in a much longer but outlying interval of 5–12 months. Side bet commitment failed to predict turnover in the short, immediate interval, but did so robustly over the longer albeit more distant interval. Normative commitment predicted turnover in neither the near term nor outmonths. Turnover rates for employees with low affective commitment were much higher than those with high affective commitment in the first quarter of a 1-year monitoring period, but subsequent turnover rates were roughly the same for the two groups. In contrast, turnover for employees with low side bet commitment was only slightly higher than the high side bet group in the first quarter, but over the remainder of the year cumulative turnover for the low side bet group exceeded that for the high side bet group by increasingly large margins. These results are consistent with theory suggesting that decrements in affective commitment (1) often occur suddenly and just prior to employees' leaving and (2) reflect general disaffection and an impetus to leave that is already exists at the point of attitude measurement. Results comport with theory describing side bet commitment as (1) an appraisal of leaving costs that, in the aggregate, are unlikely to change suddenly and (2) a relatively stable attitude that serves primarily to prevent turnover should some independent motivation to leave arise.

Influence of Pyrolysis Temperature on Biochar Property and Function as a Heavy Metal Sorbent in Soil

While a large-scale soil amendment of biochars continues to receive interest for enhancing crop yields and to remediate contaminated sites, systematic study is lacking in how biochar properties translate into purported functions such as heavy metal sequestration. In this study, cottonseed hulls were pyrolyzed at five temperatures (200, 350, 500, 650, and 800 °C) and characterized for the yield, moisture, ash, volatile matter, and fixed carbon contents, elemental composition (CHNSO), BET surface area, pH, pHpzc, and by ATR-FTIR. The characterization results were compared with the literature values for additional source materials: grass, wood, pine needle, and broiler litter-derived biochars with and without post-treatments. At respective pyrolysis temperatures, cottonseed hull chars had ash content in between grass and wood chars, and significantly lower BET surface area in comparison to other plant source materials considered. The N:C ratio reached a maximum between 300 and 400 °C for all biomass sources considered, while the following trend in N:C ratio was maintained at each pyrolysis temperature: wood≪cottonseed hull≈grass≈pine needle≪broiler litter. To examine how biochar properties translate into its function as a heavy metal (NiII, CuII, PbII, and CdII) sorbent, a soil amendment study was conducted for acidic sandy loam Norfolk soil previously shown to have low heavy metal retention capacity. The results suggest that the properties attributable to the surface functional groups of biochars (volatile matter and oxygen contents and pHpzc) control the heavy metal sequestration ability in Norfolk soil, and biochar selection for soil amendment must be made case-by-case based on the biochar characteristics, soil property, and the target function.

Surface area and pore structure properties of urethane-based copolymers containing β-cyclodextrin

The surface area and pore structure characteristics were investigated for a series of aliphatic- and aromatic-based polyurethane (PU) copolymers containing a macromolecular porogen (β-cyclodextrin). The bi-functional diisocyanates used as crosslinker units were: 1,6-hexamethylene, 4,4′-dicyclohexylmethane, 4,4′-diphenylmethane, 1,4-phenylene, and 1,5-naphthalene diisocyanate, respectively. The macromolecular porogen content was controlled by fixing the composition of β-CD and varying the co-monomer mole ratio from unity to larger integer values. Nitrogen adsorption results reveal that copolymer materials with variable mole ratios (β-CD: crosslinker) from 1:1 to 1:3 displayed relatively low BET surface areas (SA ∼ 10 1 m 2/g) and mesopore diameters (∼16–29 nm). In contrast, a dye adsorption method in aqueous solution with p-nitrophenol (PNP) at pH = 4.60 and 295 K provided estimates of the surface area (1.5–6.2 × 10 2 m 2/g) for the corresponding copolymer materials. Variation of the copolymer SA was attributed to the type of diisocyanate crosslinker and its relative mole ratio. The differences in the estimated SA values from porosimetry and the UV–Vis dye adsorption method for these nanoporous copolymers were attributed to the role of solvent as evidenced by swelling of the copolymer framework in aqueous solution and the respective temperature conditions.

Adsorption and wetting characterization of hydrophobic SBA-15 silicas

This work describes adsorption and wetting characterization of hydrophobic ordered mesoporous silicas (OMSs) with the SBA-15 motif. Three synthetic approaches to prepare hydrophobic SBA-15 silicas were explored: grafting with (1) covalently-attached monolayers (CAMs) of C n H 2 n +1Si(CH 3) 2N(CH 3) 2, (2) self-assembled monolayers (SAMs) of C n H 2 n +1Si(OEt) 3, and (3) direct (“one-pot”) co-condensation of TEOS with C n H 2 n +1Si(OEt) 3 in presence of P123 ( n = 1–18). The materials prepared were characterized by nitrogen adsorption, TEM, and chemical analysis. The surface properties of the materials were assessed by water contact angles (CAs) and by BET C constants. The results showed that, while loadings of the alkyl groups (%C) were comparable, the surface properties and pore ordering of the materials prepared through different methods were quite different. The best quality hydrophobic surfaces were prepared for SBA-15 grafted with CAMs of alkylsilanes. For these materials, the water CAs were above ∼120°/100° (adv/rec) and BET C constants were in the range of ∼15–25, indicating uniform low-energy surfaces of closely packed alkyl groups on external and internal surfaces of the pores respectively. Moreover, surfaces grafted with the long-chained (C 12–C 18) silanes showed super-hydrophobic behavior (CAs ∼ 150–180°) and extremely low adhesion for water. The pore uniformity of parental SBA-15 was largely preserved and the pore volume and pore diameter were consistent with the formation of a single layer of alkylsilyl groups inside the pores. Post-synthesis grafting of SBA-15 with SAMs worked not as well as CAMs: the surfaces prepared demonstrated lower water CAs and higher BET C constants, thereby indicating a small amount of accessible polar groups (Si–OH) related to packing constrains for SAMs supported on highly curved surfaces of mesopores. The co-condensation method produced substantially more disordered materials and less hydrophobic surfaces than any of the grafting methods. The surfaces of these materials showed low water CAs and high BET C constants (∼100–200) thereby demonstrating a non-uniform surface coverage and presence of unmodified silica. It is concluded that CAMs chemistry is the most efficient approach in preparation of the functionalized OMS materials with uniform surfaces and pores.

Catalytic performance of Ir/CeO 2 for NO–C 3H 6–O 2 reaction in a stoichiometric condition

Supported iridium catalyst was found to be highly active for NO reduction with C 3H 6 in a stoichiometric condition. Among the supported iridium catalysts tested here, Ir/CeO 2 showed the highest activity. In order to examine the influence of CeO 2 support on the catalytic performance of supported iridium, we prepared CeO 2 by precipitation method using different cerium precursors. Iridium catalyst supported on CeO 2 prepared by using Ce(IV) precursor (Ce(NH 4) 2(NO 3) 6) showed higher activity for NO reduction with C 3H 6 than that by using Ce(III) precursor (Ce(NO 3) 3·6H 2O), although the former catalyst has low BET surface area and low iridium dispersion. The activity of iridium catalyst supported on CeO 2, which was prepared by using Ce(III) precursor, calcined at different temperature was also found to increase with increasing the calcination temperature of CeO 2 support. The low activity of iridium catalyst supported on CeO 2 calcined at 600 °C was considered to be due to a strong metal support interaction (SMSI) effect by the reaction gas treatment at 600 °C, resulting in the formation of less active Ir–CeO 2 interacting species. On the other hand, the use of CeO 2 calcined at higher temperatures was found to be important to obtain a catalytically active iridium species under the stoichiometric reaction condition.

RuxTi1-xO2 as Catalyst Support for PEM Fuel Cell

Electrochemical stability and electrocatalytic activity of Pt supported on RuxTi1-xO2 were examined. The binary metal oxides were found to possess high stability during potential cycling between 0 and 1.8 V. The ECA of Pt/ RuxTi1-xO2 changes slightly after up to 1000 cycles, which suggests a strong interaction between Pt particles and the metal oxides. The synthesized RuO2 showed low BET surface areas, which may cause the low ECA and performance of Pt/ RuO2. Thus, RuxTi1-xO2 may be a promising material as a stable support for PEM fuel cells with increased specific surface area.

Removal of Carbonyl Sulfide from Syngas Using a Novel Mixed-Oxide Sorbent

In order to develop a highly sulfur capacity and reactive COS removal sorbent from syngas, Fe-Mn-Ce oxides were studied in this work. The sorbents can remove COS from 1.5% to less than 0.3 mg/m3 in appropriate conditions. Sulfur capacity of the fresh sorbent was about 20 gS/100 g sorbent in the temperature of 320–400°C. Tests showed that Fe2O3 was reduced to Fe3O4 or FeO with the simulated syngas and the presence of Fe3O4 can account for the high COS removal efficiency. The reactivity of the sorbent decreased when Fe3O4 was partially reduced to FeO. It was found that the desulfurization behavior was also influenced by the calcination temperatures, desulfurization temperatures, and gas compositions. High calcination temperature has a negative effect on the desulfurization performance of the sorbent due to lower BET. Hydrogen favors the desulfurization efficiency, whereas CO exhibits a negative effect on the COS removal.