Bench-scale Fixed-bed Reactor Research Articles

Morphologically tuned CuO-ZnO-CeO2 catalyst for CO2 hydrogenation to methanol.

Morphologically modified composite CuO-ZnO-CeO2 catalysts were synthesized using a single-step hydrothermal technique. The study highlights the influence of solvent on the structural and physico-chemical properties of the catalysts. Various techniques, such as XRD, FE-SEM, BET, XPS, and H2-TPR, were used to analyze the catalyst properties. Among the synthesized materials, the catalyst, prepared with a N,N-dimethyl formamide (DMF)-to-metal nitrates ratio of 20 (named as CZC-1), showed enhanced active sites in the form of surface features such as nanowire-like morphology, large surface area, low crystallite size, increased oxygen vacancies, and high CuO dispersion. A bench-scale fixed-bed flow reactor was used to examine the catalytic performance of the catalysts. At 225 °C reactor temperature, 30 bar reactor pressure, and with a space velocity of 6000 cm3 gcat-1 h-1, the CZC-1 catalyst showed 13.6% CO2 conversion and 74.1% methanol selectivity. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis confirmed the carbonate-formate-methoxy reaction pathway for methanol formation using the CZC-1 catalyst.

Valorisation of residual biomass by pyrolysis: influence of process conditions on products

In the context of sustainable residual biomass management, this work explores the pyrolysis process of residual biomass using a bench-scale fixed bed reactor.

Removal of Cr6+ from Synthetic Polluted Water using Fe Modified Sugarcane Bagasse & Peanut shell Powder

Unprocessed waste is dumped in lakes and rivers which possess a severe environmental risk through heavy metal’s contamination within the food chain, especially chromium Cr6+. It applies for sustainable development goals by using green solid waste as a precursor. This research mainly focuses upon the analysis of time effect for Cr6+ removal by FeCl3 modified biochar using sugarcane bagasse and peanut shell powder as biomass. Adsorbent preparation was done using Bench-Scale Fixed Bed Reactor (B-SFBR) and Cr6+ was found using the calorimetric method. Characterization was done by BET, SEM-EDX, and FTIR. The highest Cr6+ percentage removal was achieved by Modified Peanut shell Powder with 99.97% removal upon pH 2, shaking time 180 mints, speed = 150 rpm, dosage 0.3 g, Cr6+ conc 20 mg/L. Percentage Removal by Modified SB was 98.96% with Cr6+ conc 20 mg/L, dosage 0.3 g, pH 2, shaking speed 150 rpm, time 180 mints. Hence, the present experimental research concludes that FeCl3 modified peanut shell powder shows greater Cr6+ removal efficiency up to 99.97 %.

Banana pseudo-stem biochar derived from slow and fast pyrolysis process

This study evaluated the properties of banana pseudo-stem (BPS) biochar derived from two different types of pyrolysis. The fast pyrolysis experiment was performed using a worktable-scale fluidized-bed reactor, while a bench-scale fixed-bed reactor was used in the slow pyrolysis experiment. The preliminary analysis shows that the feedstock contains 80.6 db wt% of volatile matter, 12.5 db wt% of ash and 33.6% of carbon content. Biochar yield reduces as the pyrolysis temperature elevates for both pyrolysis experiments. Fast pyrolysis yields a higher percentage of biochar (40.3%) than biochar yield obtained from the slow pyrolysis experiment (34.9 wt%) at a similar temperature of 500 °C. The evaluation of biochar derived at 500 °C shows that the biochar obtained from the slow pyrolysis process has higher carbon content, heating value, and surface area with lower ash content. Meanwhile, FESEM images show significant differences in surface morphology and the number of pores for biochar derived from fast and slow pyrolysis. These findings indicate the potential and suitability of BPS biochar derived from the slow pyrolysis process in applications such as soil amelioration and solid biofuel.

Kinetic modelling and experimental validation of single large particle combustion of coal char

Understanding apparent kinetics of single large fuel particle combustion is of significance to the design and optimization of grate-firing and circulating fluidized bed boilers. Based on the concept of finite reaction zone approximation, a simple heterogeneous single particle model was formulated to consider the effects of external gas film, ash layer and chemical reaction simultaneously. To validate the proposed model and gain insight into the prevailing rate-controlling mechanism during the single particle combustion process at different combustion temperatures and particle sizes, the experiments on the combustion of coal char powder and single large char particles were carried out in a thermal gravimetric analyzer and a bench scale fixed-bed reactor, respectively. The intrinsic and apparent kinetics as well as the effective reacting zone thickness of single large particle combustion were quantified by combining theoretical analyses and experimental data. Both the bulk flow temperature and particle size have a remarkable influence on the global reactivity. The rate-controlling process was found to shift from the intrinsic chemical reaction to ash layer diffusion and return again to the intrinsic kinetics at the burnout stage. Particularly, an external effectiveness factor was defined as a function of conversion degree to better describe the ash diffusion effect on the apparent reactivity of large particles. The proposed model is physically general but simple enough to be incorporated into the computational fluid dynamic simulation of large-scale grate-firing and fluidized bed boilers.

Biochar production from sugarcane biomass using slow pyrolysis: Characterization of the solid fraction

Understanding how the type of biomass t and parameters of the pyrolysis process influence the characteristics of the biochar obtained, including its calorific value and potential as solid fuel, is important in generating alternative energy sources. In this context, this study assesses biochar production by pyrolysis of parent biomass (B), straw (S), and treated biomass (T, processed with H2SO4 0.5% (w/v) at 140 °C for 15 min). The pyrolysis process of B at 450, 550, and 650 °C, S at 450 °C, and T at 450°C was conducted in a bench-scale fixed-bed reactor at a heating rate of 10°C/min. The higher yield of biochar (50.3 wt% db) and bio-oil (26.0 wt% db) for the B was observed at 450°C. Furthermore, the biochar yields for S and T at 450 °C were 36.8 and 31.3 (wt% db), respectively. The biochar produced from B, S, and T at 450 °C shows a higher heating value of 27.9, 25.4, and 27.0 MJ/kg db, respectively. The elemental analysis of the biochar produced from the different feedstocks showed a higher C (64.91–80.93%) and a lower O content (22.58–30.5%) than the parent biomass, indicating that the biochar has good stability and potential as an energy carrier. The approach followed in this work was to contribute to a more in-depth understanding of the valorization of subproducts of the sugarcane industry through pyrolysis to produce biochar that can be used as an energy vector or material for different environmental applications, contributing to the goals of a circular bioeconomy.

Ultra-high adsorption of Hg0 using impregnated activated carbon by selenium.

Activated carbon was one of the main adsorptions utilized in elemental mercury (Hg0) removal from coal combustion flue gas. However, the high cost and low physical adsorption efficiency of activated carbon injection (ACI) limited its application. In this study, an ultra-high efficiency (nearly 100%) catalyst sorbent-Sex/Activated carbon (Sex/AC) was synthesized and applied to remove Hg0 in the simulated flue gas, which exhibited 120 times outstanding adsorption performance versus the conventional activated carbon. The Sex/AC reached 17.98 mg/g Hg0 adsorption capacity at 160 °C under the pure nitrogen atmosphere. Moreover, it maintained an excellent mercury adsorption tolerance, reaching the efficiency of Hg0 removal above 85% at the NO and SO2 conditions in a bench-scale fixed-bed reactor. Characterized by the multiple methods, including BET, XRD, XPS, kinetic and thermodynamic analysis, and the DFT calculation, we demonstrated that the ultrahigh mercury removal performance originated from the activated Se species in Sex/AC. Chemical adsorption plays a dominant role in Hg0 removal: Selenium anchored on the surface of AC would capture Hg0 in the flue gas to form an extremely stable substance-HgSe, avoiding subsequent Hg0 released. Additionally, the oxygen-containing functional groups in AC and the higher BET areas promote the conversion of Hg0 to HgO. This work provided a novel and highly efficient carbon-based sorbent -Sex/AC to capture the mercury in coal combustion flue gas. Graphical abstract Selenium-modified porous activated carbon and the interface functional group promotes the synergistic effect of physical adsorption and chemical adsorption to promote the adsorption capacity of Hg0.

Effects of SO3 formation on high temperature flue gas desulphurization performance

The removal of SO2 from a synthetic flue gas using limestone sorbent was investigated. The formation of SO3 in situ was quantified and its effect on the desulphurization performance of the sorbent was determined. The transient response was measured in a bench-scale fixed-bed reactor at 700 °C, 800 °C and 900 °C, and under inert and catalytic wall conditions. Under the homogeneous gas-phase reaction conditions (inert wall effects), it was found that the breakthrough times increased as the temperature increased, indicating an increasing sorbent capacity. The SO3 molar yields under these conditions were found to remain constant at 0.24% at all temperatures. It was found that after the pickling and cleaning of the reactor vessel, the iron oxide on the exposed stainless steel reactor walls had catalytically accelerated the conversion of SO2 to SO3 as the temperature increased. Longer breakthrough times were thus obtained for SO2 removal and increased SO3 molar yields of 1.62%, 2.8% and 4.65% were obtained at each of the temperatures, respectively. The increasing SO3 molar yield had an adverse effect on the desulphurization performance of the sorbent as indicated by decreasing desulphurization ratios (0.95, 0.91 and 0.864), where the desulphurization ratio is the ratio of the actual degree of desulphurization to the apparent degree of desulphurization. It was determined that under these mild desulphurization conditions, the conversion of SO2 to SO3 influences the overall desulphurization performance of the hot-gas system, with increased effects at higher temperatures and a catalytically active reactor wall.

Kinetic mechanism on elemental mercury adsorption by brominated petroleum coke in simulated flue gas.

A waste byproduct of petroleum coke was obtained as a precursor modified with bromine for elemental mercury capture from simulated flue gas on a bench scale fixed-bed reactor. The reaction temperature, the initial inlet elemental mercury concentration and the individual flue gas components of O2, NO, SO2 and HCl were determined to explore their influence on elemental mercury capture by the brominated petroleum coke. Results indicate that high initial inlet mercury concentration can enhance initial mercury accumulation and the optimal temperature for elemental mercury capture by brominated petroleum coke is about 150 °C. Kinetic models reveal that the pseudo-second order and Elovich models are best fitted to the mercury adsorption process, indicating that chemisorption is the control step with the intra-particle diffusion and external mass transfer taking place simultaneously. The kinetic parameters demonstrate that the initial mercury adsorption rate (h or a) and the equilibrium adsorption quantity (Qe) increase remarkably, when higher concentrations of O2 or NO exist in N2 atmosphere. On the contrary, Qe decreases with the presence of high SO2 or HCl, which indicates a two-sided effect on the performance of mercury adsorption owing to their concentrations.

Upgrading of banana leaf waste to produce solid biofuel by torrefaction: physicochemical properties, combustion behaviors, and potential emissions.

This study is the first report that focuses on investigating the effects of torrefaction on the bioenergy-related properties, combustion behavior, and potential emissions of banana leaf waste (BLW). Experiments were first conducted in a bench-scale fixed-bed reactor operating at light (220 °C), mild (250 °C), and severe (280 °C) torrefaction conditions to torrefy the raw BLW. Torrefaction pretreatments reduced the weight of the raw BLW by about 60%, but the resulting solid biofuel can preserve up to 77% of the energy content of the raw biomass. It was found that torrefied BLW contains more concentrated fixed carbon than the raw BLW, volatile matter content of up to 59.8 wt.%, and a higher HHV of up to 20.7 MJ kg-1 with higher concentrations of carbon, nitrogen, and ash. Bulk density increased 13.0% over the raw BLW, and the torrefied BLW became a solid biofuel with 51.5% greater energy density under the severe torrefaction condition. The upgrading of BLW by torrefaction enhanced its combustion performance in terms of comprehensive combustion, ignition, burnout, and flammability indices. Compared with commercial hard coal, BLW torrefied at the mild condition (250 °C) had lower potential emissions per unit of energy, 25.3% less CO2 emission, 3.1% less CO emission, 96.4% less SO2 emission, and 18.4% less dust emission, except for NOX emission. This study conclusively indicates that BLW after torrefaction has enhanced bioenergy-related properties, improved combustion performance, and reduced emissions potential, proving to be a promising method for its valorization.

Gas-phase elemental mercury removal by bamboo charcoal impregnated with KMnO4: mechanism study

Bamboo charcoal is made from biomass with porous structure. The performance of bamboo charcoal (BC) and KMnO4-modified BC was studied with a bench-scale fixed-bed reactor. X-ray photoelectron spectroscopy, X-ray diffraction, elemental analysis and BET surface area analysis were used to determine the physical and chemical property of the sorbents. The results show that the modification increased the oxygen functionalities and π electrons, which facilitate the mercury oxidation on sorbent surface and act as possible active centers for elemental mercury.

A comprehensive study on upgradation of pyrolysis products through co-feeding of waste tire into rice straw under broad range of co-feed ratios in a bench-scale fixed bed reactor

A comprehensive study investigating all co-pyrolysis products (bio-oil, char, and gas) utilizing bench-scale reactor is essential for potential use in upscaling and techno-economic analysis for commercialization and integration of pyrolysis with conventional systems. This study explores the co-pyrolysis of rice straw (RS) and waste tire (WT) to assess the impact on products under a broad range of feedstock ratio (20, 40, 60, and 80 wt% of WT into RS) in fixed bed reactor at 550 °C. Results revealed that feedstock mass ratio played a crucial role to transform the oxygenates into hydrocarbons (HCs). Liquid yield, organic phase, pH, aromatics, and olefins increased with increase of WT proportion in blend. Bio-oil yield, aromatics and olefins reached to 45 wt%, 42%, and 30% at WT/RS (80:20) compared to 36 wt%, 2%, and 4% in the case of RS alone, respectively. Likewise, at the same blend ratio, 85% reduction in oxygenates was observed while higher heating value (HHV) of bio-oil (41.40 MJ/kg) was comparable to that of WT (41.50 MJ/kg). Significant positive synergy was achieved for non-condensable gas after incorporation of WT into RS. Hydrogen (H2) and methane (CH4) along with higher HCs were increased while oxides of carbon reduced with the addition of WT compared to RS alone. Char characteristics also improved with addition of WT into RS in terms of increased carbon content, HHV, and reduced ash content.

Catalytic Conversion of Free Fatty Acids to Bio-Based Aromatics: A Model Investigation Using Oleic Acid and an H-ZSM-5/Al2O3 Catalyst.

The catalytic conversion of oleic acid to aromatics (benzene, toluene, and xylenes, BTX) over a granular H-ZSM-5/Al2O3 catalyst (ϕ 1.2–1.8 mm, 10 g loading) was investigated in a continuous bench-scale fixed-bed reactor (10 g oleic acid h–1). A peak carbon yield of aromatics of 27.4% was obtained at a catalyst bed temperature of 550 °C and atmospheric pressure. BTX was the major aromatics formed (peak carbon yield was 22.7%), and a total BTX production of 1000 mg g–1 catalyst was achieved within a catalyst lifetime of 6.5 h for the fresh catalyst. The catalyst was deactivated due to severe coke deposition (ca. 22.1 wt % on the catalyst). The used catalyst was reactivated by an ex situ oxidative regeneration at 680 °C in air for 12 h. The regenerated catalyst was subsequently recycled, and in total, 7 cycles of reaction-regeneration were performed. A gradual decrease in the peak carbon yield of BTX was observed with reaction-regeneration cycles (e.g., to 16.3% for the catalyst regenerated for 6 times). However, the catalyst lifetime was remarkably prolonged (e.g., >24 h), leading to a significantly enhanced total BTX production (e.g., 3000 mg g–1 catalyst in 24 h). The fresh, used, and regenerated catalysts were characterized by N2 and Ar physisorption, XRD, HR-TEM-EDX, 27Al, and 29Si MAS ssNMR, NH3-TPD, TGA, and CHN elemental analysis. Negligible changes in textural properties, crystalline structure, and framework occurred after one reaction-regeneration cycle, except for a slight decrease in acidity. However, dealumination of the H-ZSM-5 framework was observed after 7 cycles of reaction-regeneration, leading to a decrease in microporosity, crystallinity, and acidity. Apparently, these changes are not detrimental for catalyst activity, and actually, the lifetime of the catalyst increases, rationalized by considering that coke formation rates are retarded when the acidity is reduced.

Jatropha curcas L. biomass transformation via torrefaction: Surface chemical groups and morphological characterization

The effect of torrefaction on the chemical compositions and surface morphology of raw and pretreated (dilute acid and mild alkaline) of Jatropha curcas L. seed shell (JSS) and fruit hull (JFH) were investigated using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The biomass samples were torrefied using a bench-scale fixed bed reactor (torrefaction device), which was developed by the authors. The raw and pretreated biomass was heated in an oxygen-free environment or oxygen-reduced condition at 200–300 ​°C using particle size of 1.14 ​mm, and residence time of 30 ​min. The FTIR data of the raw, treated and torrefied biomass bands were similar. The O–H stretch peak (hydrogen bonded) around 3763-3200 ​cm−1 is visible in all the samples. The infrared spectra revealed the presence of the peak between 2800 ​cm−1 and 3000 ​cm−1 corresponding to the presence of the aliphatic groups (C–H stretching) in the raw and pretreated samples. Band waves between 900 ​cm−1 and 700 ​cm−1 indicated aromatic C–H deformation in all samples and much more. The chemical components of the JSS and JFH were changed after pretreatment with H2SO4 and NaOH. The SEM images of the raw JSS revealed a highly dense structure which are coarsely grained. The microparticles are rough and multidispersed with significant pore aperture. The SEM image of raw JFH had cracked, fibrous tissue with a relatively smooth surface while the pretreated samples had large number of pores. The acid and alkali pretreatment enhanced the surface structure.

Experimental Investigation of Fast Pyrolysis of Isoberlina doka-Derived Sawdust for Bio-Oil Production

Fast pyrolysis is considered an emerging technology for biomass conversion into liquid oil. In this paper, the conversion of waste from Isoberlina doka tree processing into bio-oil using a bench-scale fixed bed reactor with a fluidized behavior within the bed zone has been investigated at temperatures of 400–500 °C and particle size ranges of < 0.5 and 0.5–1 mm. Reactor with the total height of 140 mm consisting of three zones with gas inlet diameter of 10 mm, reaction zone diameter of 70 mm, outlet diameter of 15 mm and a coupled detachable inlet with a diameter 15 mm for biomass loading was used for experimentation. Nitrogen was used as the carrier gas, and the products were biochar, bio-oil and non-condensable gas. Thermogravimetric and derivative thermal analysis (TG/DTA) was carried out in order to understand the thermal behavior of wood particles. Bio-oil produced was analyzed using the gas chromatography mass spectrometry and the Fourier transform infra-red spectrophotometry methodologies. TG/DTA analysis revealed an initial 30.639% mass loss which correlates to hardwood thermal characteristics. Bio-oil yield from bench-scale pyrolysis increased with increasing temperature. A maximum bio-oil yield of 49.84 wt % was observed at the particle size range of 0.5–1 mm, bed temperature of 500 °C and time of 30 min. Volatile generation was at the peak of 54.54% (0.002655 kg/min). However, changes in the chemical composition and functional groups of bio-oil with temperature of production suited it for different usage purposes.

Enhanced pyrolysis of palm kernel shell wastes to bio-based chemicals and syngas using red mud as an additive

In the present study, the red mud (RM, a waste from aluminium industry) was employed to catalyze the pyrolysis of palm kernel shell (PKS, a waste from palm oil generation industry) to produce bio-chemicals and syngas using a bench scale fixed bed reactor. The composition of the achieving bio-oil was determined by a GC/MS analyzer. The results show that RM could promote the conversion of PKS biochar and bio-oil to non-condensable gases during the pyrolysis process of PKS. The addition of RM enhanced the decomposition of oxygen-containing functional groups and double bonds in side chains on benzene rings, resulting in the formation of phenol and aromatics accounting for 85.61 area% in bio-oil. Moreover, the total energy-based yield of gaseous and liquid products reached up to 87% at 800 °C with a PKS/RM mass ratio of 1:1.8. The steam gasification reactivity of PKS biochar was also significantly improved with the addition of RM. The findings imply that RM is a promising additive that allows the utilization of PKS waste riched in lignin component to generate valuable products via pyrolysis.

Preparation of fly ash adsorbents utilizing non-thermal plasma to add S active sites for Hg0 removal from flue gas

This paper proposed a method of preparing efficient, cost-effective and eco-friendly fly ash (FA) adsorbents utilizing non-thermal plasma technology in H2S atmosphere to remove elemental mercury (Hg0) in the coal-fired flue gas. Characterization of fly ash samples showed plasma treatment had little effect on porous structure, surface morphology and crystal structure of fly ash samples. It was found that elemental sulfur (S) particles, which were active site for Hg0 removal, was incorporated successfully on the adsorbents’ surface. The loaded S particles showed superior Hg0 oxidation ability and low remission possibility. The Hg0 removal experiments were conducted in a bench-scale fixed-bed reactor. After plasma treatment, the initial Hg0 removal efficiency of modified fly ash had increased significantly compared to raw fly ash (2.8–3.6 times). The effects of treatment time (0.5–5 min), adsorption temperature (60–180 °C) and flue gas components on Hg0 removal efficiency were also analyzed in the present study. The Hg0 removal efficiency had a positive correlation with adsorption temperature. HCl, O2 and NO in the flue gas could promote the removal of Hg0, whereas SO2 had an adverse effect. The Hg0 adsorption performance was better with longer treatment time largely due to more S was loaded on the fly ash surface, which was confirmed by XPS and SEM results. Additionally, the temperature-programmed decomposition (TPD) experiments further proved existing species of mercury in used modified fly ash were black HgS and red HgS. Finally, the mechanism of fly ash adsorbents modified by non-thermal plasma technology to remove Hg0 was proposed.

Performances of syngas production and deposited coke regulation during co-gasification of biomass and plastic wastes over Ni/γ-Al2O3 catalyst: Role of biomass to plastic ratio in feedstock

In order to improve the quality of syngas and regulate the deposited coke, co-gasification of biomass and polyethylene wastes without and with steam were investigated in a bench-scale fixed bed reactor, where the feedstock was pyrolyzed at the temperature of 600 °C followed by catalytic reforming at 800 °C over Ni/γ-Al2O3 catalyst. The influences of different biomass to plastic ratios in feedstock on the quality of gas products were analyzed by means of gas chromatography. The as-formed deposited coke was examined by TEM, Raman, FTIR and TPO analysis. The results showed a synergistic effect on both gas and tar yields when PE was co-fed to RH, especially at PE content of 50%. For higher PE content (>50%), the total gas and H2 decreased due to more chain hydrocarbons with relatively large molecular size derived from PE volatiles being more difficult to be cracked than oxygenates from pyrolysis of biomass. Two natures of the deposited coke were identified as amorphous carbon and multi-walled carbon nanotubes (CNTs). With increasing PE proportion, CNTs growth exhibited a denser distribution with uniform diameter (~18 nm) and longer tube walls extending to a few microns. In the absence of steam, amorphous carbons was the leading type in coke depositions. The introduction of steam improved the quality and purity of CNTs and decreased amorphous carbon remarkably, owning to a stronger interaction between steam and amorphous carbon rather than CNTs with high graphitization, leading to high CNTs proportion of 61.5%. A significant synergistic effect on the CNT growth was observed particularly for 50–75% of PE. The CNT-predominated deposited coke slowed down the deactivation rate of catalysts, thus producing positive impact to total gas production.

Pyrolysis study of hydrothermal carbonization-treated digested sewage sludge using a Py-GC/MS and a bench-scale pyrolyzer

The disposal of digested sewage sludge is becoming a global problem. Hydrothermal carbonization (HTC) combined with the pyrolysis of digested sewage sludge was investigated by using a new conversion route for the exploitation of sewage sludge in energy applications. The thermochemical properties of the material were investigated by using HTC pre-treatments, thermogravimetric analyses, pyrolysis tests in Py-GC/MS and a bench-scale fixed bed reactor at temperatures of 450, 550, and 650 °C. It was found that the thermal decomposition of the hydrothermally treated digested sewage sludge takes place in a two-stage reaction. After pyrolysis, the ash in the sample was oxidized in the O2 atmosphere at 900 °C. Therefore, a new characterization method for determination of the non-oxdized ash content and fixed carbon content was proposed. The result from Py-GC/MS shows that the abundance of aromatic hydrocarbons in pyrolytic vapors present a positive correlation with increased temperature. In the bench-scale experiments, the highest HHV of the organic fraction was obtained at 650 °C as 38.46 MJ/kg.

Efficient Removal of Elemental Mercury from Coal-Fired Flue Gas over Sulfur-Containing Sorbent at Low Temperatures.

In the work, sulfur-containing sorbents were employed to remove elemental mercury (Hg0) from coal-fired flue gas. The work used the thermogravimetric analysis, Brunauer–Emmett–Teller method, scanning electron microscopy with energy-dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy to characterize the physicochemical properties of the sorbents. The Hg0 removal performance of these used sorbents from the simulated coal-fired flue gas was evaluated by a bench-scale fixed-bed reactor. The results indicated that a generous amount of elemental sulfur covered the surface and pore structure of the used sorbent. With the rise of H2S selective oxidation temperature, both the sulfur content and specific surface area decreased rapidly. Used-Fe/SC120 could achieve the mercury removal efficiency of above 90% at 90 °C. The high temperature was not conducive to the mercury capture due to the release of surface elemental sulfur. The presence of O2 and SO2 inhibited Hg0 removal in different degrees because of the decreased active sulfur sites and competitive adsorption. Meanwhile, NO promoted the Hg0 removal efficiency by enhancing the Hg0 oxidation. The further analysis showed that the surface elemental sulfur was vital to capture the Hg0 from coal-fired flue gas, which reacted with Hg0 to form HgS.