Simulated Flue Gas Research Articles

Hydrophobic hyper-cross-linked polymer shells encapsulating dispersed nanoscale CuS boosting mercury immobilization

Metal sulfides (MSs) hold significant promise for environmental remediation but are hindered by their low accommodation capacity and poor water resistance. Herein, this work reports a hybrid strategy to address these limitations by assembling highly dispersed CuS nanoparticles within the hyper-cross-linked polymer (HCP). Benefiting from the super-hydrophobicity and well-developed porosity of HCP, alongside the high dispersion and multiple active sites of CuS nanoparticles, the resultant CuS@HCP exhibits exceptional water resistance, enhanced surface area, high mass transfer ability, and substantial Hg0 adsorption capacity. The Hg0 adsorption capacity (Q90) of CuS@HCP3 reaches 1.25 and 1.391 mg/g under N2 and simulated flue gas, respectively. Notably, the normalized Q90 of coated CuS surpasses that of pristine CuS by 25-fold under N2 + 15 % H2O and its durability outstrips most previously reported mineral sulfides even in complex simulated flue gas. Universal research confirms MSs@HCP (M = Zn, Sn, and Fe) equally demonstrate over 15-fold increment in Hg0 retention under high humidity conditions compared to the pristine MSs. Such HCP hybrid strategy universally and effectively optimizes the accommodation capacity and water resistance of MSs, endowing MSs@HCP broad application prospects.

Influence of Absorbent Composition and Operating Parameters on CO2 Removal Efficiency Using Aqueous Blends of 1-Dimethylamino-2-propanol in Tray Column

The CO2 absorption performance in aqueous blends of monoethanolamine (MEA)—1-dimethylamino-2-propanol (DMA2P) and piperazine (PZ)—DMA2P was investigated using a bench-scale tray column under atmospheric pressure. The removal efficiency of CO2 (ηCO2) and the overall volumetric mass transfer coefficient (KGav) in DMA2P-MEA and DMA2P-PZ solutions were determined at 313.2 K. The simulated flue gas was composed of 15% (mole fraction) CO2 and 85% N2. The effects of inlet gas flow rate (G), absorbent composition (w), inlet liquid flow rate (L), and plate number (NP) on ηCO2 and KGav were demonstrated. Our results showed that the absorption of CO2 in DMA2P aqueous solution can be accelerated by the addition of MEA/PZ in a tray column, and both ηCO2 and KGav can be significantly improved.

Online in-situ modification of biochar for the efficient removal of elemental mercury and co-benefit of SO2/NO removal

In this study, non-thermal plasma discharge was proposed for online in-situ modification of biochar injected into coal-biomass co-combustion flue gas, aiming to achieve the combined removal of elemental mercury (Hg0), NO, and SO2 from flue gas. After plasma discharge, the pore structure of biochar was slightly improved whereas the surface morphology of biochar was almost unchanged. After plasma discharge under O2, SO2, and HCl atmospheres, the oxygen, sulfur, and chlorine contents of biochar were obviously increased. More exactly, additional functional groups were formed on the modified biochar surface, such as CO, C(O)OC, CS, and CCl. Compared with raw biochar, the biochar modified under HCl, SO2, O2, H2O and CO2 atmospheres exhibited higher Hg0 removal efficiency, and longer modification time resulted in better Hg0 removal performance. The optimal modification atmosphere and reaction temperature were the simulated flue gas (SO2 + HCl + CO2 + O2 + H2O + NO + N2) and 20 ℃-100 ℃, respectively. The modified biochar exhibited excellent resistance to SO2 and H2O. The addition of HCl, CO2, NO, and O2 contributed to Hg0 removal. The removal efficiency of NO and SO2 attained a maximum of 100 %. The Hg0 removal mechanism was further revealed, where CO, C(O)OC, CS, and CCl served as active components.

Tailoring d‑Band Center of Single-Atom Nickel Sites for Boosted Photocatalytic Reduction of Diluted CO2 from Flue Gas.

Photocatalytic reduction of diluted CO2 from anthropogenic sources holds tremendous potential for achieving carbon neutrality, while the huge barrier to forming *COOH key intermediate considerably limits catalytic effectiveness. Herein, via coordination engineering of atomically scattered Ni sites in conductive metal-organic frameworks (CMOFs), we propose a facile strategy for tailoring the d‑band center of metal active sites towards high-efficiency photoreduction of diluted CO2. Under visible-light irradiation in pure CO2, CMOFs with Ni-O4 sites (Ni-O4 CMOFs) exhibits an outstanding rate for CO generation of 13.3 μmol h-1 with a selectivity of 94.5%, which is almost double that of its isostructural counterpart with traditional Ni-N4 sites (Ni-N4 CMOFs), outperforming most reported systems under comparable conditions. Interestingly, in simulated flue gas, the CO selectivity of Ni-N4 CMOFs decreases significantly while that of Ni-O4 CMOFs is mostly unchanged, signifying the supremacy for Ni-O4 CMOFs in leveraging anthropogenic diluted CO2. In-situ spectroscopy and density functional theory (DFT) investigations demonstrate that O coordination can move the center of the Ni sites' d-band closer to the Fermi level, benefiting the generation of *COOH key intermediate as well as the desorption of *CO and hence leading to significantly boosted activity and selectivity for CO2-to-CO photoreduction.

The effects of different functional groups in Ni3-cluster MOFs on the efficient capture and transformation for flue gas CO2

As the greenhouse effect continuous increasing, the efficient CO2 capture and conversion into high-value fine chemicals have been necessary and meaningful. However, the CO2 coupling reaction always requires harsh catalytic reaction conditions and focuses on pure CO2 gas. Herein, three nickel-cluster metal-organic frameworks (MOFs) with different functional groups on the bridging-ligands have been synthesized and characterized structurally, presenting unique cages and channels architectural features. Catalytic investigations demonstrated that the amino-functionalized MOFs as a catalyst {[H2N(CH3)2]2[Ni3(µ3-O)(XN)(BDC-NH2)3∙7DMF}n (Ni3-NH2, XN = 6′′-(pyridin4-yl)-4,2′′:4′′,4′′′-terpyridine, H2BDC-NH2 = 2-aminoterephthalic acid) owns higher catalytic activity (96 %) than the other two in the CO2 transformation reaction with aziridine into oxazolidinones under 0.5 MPa within 4 h. Moreover, Ni3-NH2 can be reused at least ten times without significant catalytic activity loss under mild condition. Importantly, Ni3-NH2 catalyst still can be applicable to the simulating flue gas with 15 % CO2 as carbon source. The mechanism has been further revealed by NMR, FT-IR and DFT calculations, in which the Ni-site and the amino group can synergistically activate the substrate and CO2 molecule. This work has enriched the species of cluster-based MOFs and investigated the influence of characteristic functional groups on the catalytic activity deeply.

Dual Metallosalen-based Covalent Organic Frameworks for Artificial Photosynthetic Diluted CO2 Reduction.

Directly converting CO2 in flue gas using artificial photosynthetic technology represents a promising green approach for CO2 resource utilization. However, it remains a great challenge to achieve efficient reduction of CO2 from flue gas due to the decreased activity of photocatalysts in diluted CO2 atmosphere. Herein, we designed and synthesized a series of dual metallosalen-based covalent organic frameworks (MM-Salen-COFs, M: Zn, Ni, Cu) for artificial photosynthetic diluted CO2 reduction and confirmed their advantage in comparison to that of single metal M-Salen-COFs. As a results, the ZnZn-Salen-COF with dual Zn sites exhibits a prominent visible-light-driven CO2-to-CO conversion rate of 150.9 μmol g-1 h-1 under pure CO2 atmosphere, which is ~6 times higher than that of single metal Zn-Salen-COF. Notably, the dual metal ZnZn-Salen-COF still displays efficient CO2 conversion activity of 102.1 μmol g-1 h-1 under diluted CO2 atmosphere from simulated flue gas conditions (15% CO2), which is a record high activity among COFs- and MOFs-based photocatalysts under the same reaction conditions. Further investigations and theoretical calculations suggest that the synergistic effect between the neighboring dual metal sites in the ZnZn-Salen-COF facilitates low concentration CO2 adsorption and activation, thereby lowering the energy barrier of the rate-determining step.

Dual Metallosalen‐based Covalent Organic Frameworks for Artificial Photosynthetic Diluted CO2 Reduction

Directly converting CO2 in flue gas using artificial photosynthetic technology represents a promising green approach for CO2 resource utilization. However, it remains a great challenge to achieve efficient reduction of CO2 from flue gas due to the decreased activity of photocatalysts in diluted CO2 atmosphere. Herein, we designed and synthesized a series of dual metallosalen‐based covalent organic frameworks (MM‐Salen‐COFs, M: Zn, Ni, Cu) for artificial photosynthetic diluted CO2 reduction and confirmed their advantage in comparison to that of single metal M‐Salen‐COFs. As a results, the ZnZn‐Salen‐COF with dual Zn sites exhibits a prominent visible‐light‐driven CO2‐to‐CO conversion rate of 150.9 μmol g−1 h−1 under pure CO2 atmosphere, which is ~6 times higher than that of single metal Zn‐Salen‐COF. Notably, the dual metal ZnZn‐Salen‐COF still displays efficient CO2 conversion activity of 102.1 μmol g−1 h−1 under diluted CO2 atmosphere from simulated flue gas conditions (15% CO2), which is a record high activity among COFs‐ and MOFs‐based photocatalysts under the same reaction conditions. Further investigations and theoretical calculations suggest that the synergistic effect between the neighboring dual metal sites in the ZnZn‐Salen‐COF facilitates low concentration CO2 adsorption and activation, thereby lowering the energy barrier of the rate‐determining step.

Synthesis of porous hypercrosslinked polymers from waste polystyrene for efficient CO2 separation

A series of porous hypercrosslinked polymers (HCP-x) were synthesized from waste polystyrene foam via Fridel-Crafts alkylation reaction, aiming to optimize the utilization of waste plastics. The impact of various crosslinkers on the structural characteristics and CO2 adsorption properties of HCP-x was investigated. The results indicated that HCP-x polymers possess high specific surface areas spanning 830–1182 m2 g−1, abundant narrow micropores, and exceptional thermal stability. Notably, HCP-2 exhibited the highest CO2 adsorption capacity of 2.77 mmol g−1 at 273 K and 1.0 bar. These hypercrosslinked polymers also demonstrated a favorable CO2/N2 ideal selectivity and robust cyclic adsorption performance. Breakthrough experiments confirmed the selective adsorption of CO2 from simulated flue gas containing CO2/N2 (15/85). Additionally, the mechanism underlying CO2 adsorption on HCP-x was elucidated by analyzing adsorption thermodynamics and diffusion kinetics. This study not only introduces an innovative method for recycling waste polystyrene foam but also underscores the potential of HCP-x as an effective adsorbent for CO2 capture.

Mechanism of CeO2 modified CO2 adsorbent with SO2 resistance: Experimental and DFT study

The flue gas emitted from coal-fired boilers contains a trace amount of SO2 after desulfurization, resulting in poor performance of CO2 adsorbent. In this paper, CO2 adsorption performance of potassium adsorbent modified by CeO2 doping and the effect of SO2 on CO2 adsorption were investigated by simulated flue gas. Theoretical research on the reaction between SO2 and CO2 with dopant was conducted by Density Functional Theory (DFT) method. The results showed that the cumulative CO2 adsorption capacity of the 4% Ce doped adsorbent without SO2 and with SO2 were 10.2% and 53.6% higher than that of the undoped adsorbent. The oxygen vacancy could cause the f orbital of Ce to exert greater influence, making the surface properties more unstable. The activation energy of the adsorption reaction between SO2 and H2O on Ce doped adsorbent was 266.5 kJ/mol, and there were three transition states in this reaction, with O vacancy formation as the rate-controlling step.

Synthesis and Optimization of 3D Porous Polymers for Efficient CO2 Capture and H2 Storage

In this study, a new porous organic polymer (KFUPM-CO2) with intrinsic nitrogen atoms as active sites for CO2 capture was optimized and synthesized via Friedel-Crafts alkylation of triptycene and 2,2-bipyridine. The porous polymer shows a high surface area of 1100 m2/g with a tuned microporosity of less than 1.2 nm, confirmed by NLDFT. KFUPM-CO2 showed a remarkable CO2 sorption capacity of 5.6 mmol/g at 273 K, 3.2 mmol/g at 298 K, and a pressure of 760 mmHg. KFUPM-CO2 showed a high enthalpy of adsorption of 43.7 kJ/mol for CO2 with IAST selectivity of CO2/N2 of 127 at 273 K and 97 at 298 K on simulated flue gas composition. Additionally, KFUPM-CO2 exhibited an H2 storage capacity of 1.5 wt. % at 77 K and 860 mmHg. Grand Canonical Monte Carlo (GCMC) simulations further revealed that KFUPM-CO2 was mainly stabilized by π-π intra-molecular interactions, and exhibited strong van der Waals attractions to CO2 molecules via the pyridyl nitrogen atoms, resulting in the rapid uptake. The combined advantages of binding 2,2-bipyridine with triptycene provided a robust porous polymer with abundant nitrogen sites, permanent porosity, and thermal stability, rendering KFUPM-CO2 an excellent candidate for CO2 capture and H2 storage technologies.

Development of efficient CO2 adsorbents: Synthesis and performance evaluation of dopamine-modified halloysite nanotubes loaded with ZIF-8

Carbon capture, utilization, and storage (CCUS) is a crucial technology for achieving carbon reduction targets. The key to CCUS technology lies in developing and designing efficient and low-cost CO2 capture materials. Metal-organic frameworks (MOFs) have emerged as promising CO2 adsorbents in the field of carbon capture. However, high agglomeration of nanoparticles and high cost have severely hindered the application of MOF-based solid adsorbents. This study employs an in-situ growth method to prepare a novel “corncob-shaped” PHNT@ZIF-8 composite material. During the reaction process, surface modification of halloysite nanotubes (HNT) enhances the interaction between HNT and ZIF-8. The resulting PHNT@ZIF-8 exhibits an enhanced CO2 adsorption capacity of 1.48 mmol/g. Notably, the functionalized PHNT@ZIF-8 as CO2 adsorbents demonstrated significant adsorption properties: a high specific surface area of 409.74 m2/g, good selectivity in simulated flue gas composition of 15%/85% (CO2/N2) (39.1), excellent thermal stability, and superior regenerability. Moreover, PHNT@ZIF-8 adsorbs CO2 primarily through van der Waals forces, which involve low energy and are easily reversible. After eight adsorption–desorption cycles, CO2 capacity retention rate remains as high as 93% (1.37 mmol/g). This work enriches the repertoire of solid CO2 composite adsorbents, providing a novel pathway for enhancing CO2 adsorption performance.

In situ hydrolyzed microporous polymer membranes for additional free volume to facilitate CO2 permeation

Advancements in membrane separation technology play a pivotal role in separation processes closely associated with the environment and energy. However, presently available commercial polymeric membranes encounter the challenge of low permeability, impacting both separation efficiency and membrane module costs. Here, we propose a simple and effective in situ acid hydrolysis strategy to significantly enhance membrane permeability. Specifically, a tetrafluorinated monomer with hydrolyzable Schiff base groups (TFNAD) has been meticulously designed, synthesized, and copolymerized with commercial TFTPN and TTSBI, yielding a series of copolymers. Subsequently, in situ hydrolysis removes aniline from the membrane, freeing up the occupied free volume and creating additional channels for gas transport. This process substantially enhances gas permeability while preserving the desired selectivity. PIM-TFAD-30 showed a 68 % improvement in CO2 permeability with virtually no compromise in CO2/N2 selectivity compared to the pre-hydrolysis membrane. Meanwhile, PIM-TFAD-30 also displayed outstanding separation performance and plasticization resistance in simulated flue gas tests, demonstrating its potential for practical application. This facile and straightforward hydrolysis method opens up a new perspective for preparing and modifying polymeric separation membranes beyond gas separation.

Investigation into the wet purification of NO from simulated flue gas utilizing hydroxylamine-enhanced iron ion-activated ammonium persulfate system

Promoting NO dissolution and absorption is the key issue to break through wet denitrification technology. The Fe2+/ammonium persulfate (APS) system exhibits rapid and efficient reaction with liquid-phase NO, facilitated by the generation of highly active ·OH and ·SO4–. However, the gradual accumulation of Fe3+ and sluggish conversion to Fe2+ ultimately impede the NO purification efficacy. In this paper, the reductant hydroxylamine (HA) was introduced into the Fe2+/APS system to expedite Fe2+ regeneration, thereby enhancing the system's oxidizing capability for NO purification in simulated flue gas. Employing a bubbling reactor, (NH4)2S2O8 served as the absorbent, Fe2+ as the activator, HA as the reductant, and the mixture of NO and N2 as the simulated flue gas (initial NO concentration of 700 ppm). The effects of APS concentration, temperature, Fe2+ concentration, and HA concentration on NO purification rate were investigated. The mechanism of HA in the Fe2+/APS system was analyzed by measuring the concentrations of APS and Fe2+ in the solution. Furthermore, the reaction pathway of NO purification in the APS/Fe2+/HA system was elucidated using electron paramagnetic resonance (ESR) radical trapping and radical burst experiments under optimized process parameters. It was shown that the NO purification rate could reach 71.79 % under the operating conditions of temperature of 30°C, Fe2+ concentration of 0.01 mol·L−1, APS concentration of 0.2 mol·L−1, and HA concentration of 0.03 mol·L−1. The addition of HA accelerated Fe3+ to Fe2+ conversion and facilitated APS decomposition, leading to increased ·SO4– and ·OH production, thus maintaining a higher denitrification efficiency. ESR free radical trapping experiments demonstrated that ·OH and ·SO4– were the main free radicals present in the APS/Fe2+/HA system for NO purification. Free radical burst experiments revealed ·SO4– contribution at 32.09 % and ·OH contribution at 47.21 %, and ·OH generation followed multiple pathways. The wet purification of NO using the hydroxylamine-enhanced iron ion-activated persulfate system has the advantages of small footprint, simple operation, no secondary pollution and mild conditions, presenting a superior wet NO purification technology with potential for future applications, particularly in small and medium-sized industrial boilers.

Insight into the adsorption mechanism of arsenic and selenium by different mineral adsorbents

The adsorption characteristics of arsenic and selenium by CaO, CaCO3, MgO and Fe2O3 at different temperatures and the influence of steam are investigated using simulated flue gas by a vertical furnace. Experiments show that the adsorption capacity of CaCO3 for arsenic and selenium reached the maximum at 900 °C. Steam addition exerts a notable inhibitory impact on the adsorptive efficacy of CaO, MgO, and Fe2O3. Low-concentration steam has a certain improvement on adsorption of arsenic by CaCO3, while excessive steam will have an inhibitory effect. Based on CaCO3, the adsorption effect of composite minerals is investigated. When the mass ratio of CaCO3 and Fe2O3 is 3:1, the best adsorption is achieved, attributing to the generated Ca2Fe2O5 at high temperature. It is verified in the drop tube furnace. The relative enrichment factor of As and Se are 88.24 % and 75.11 %, respectively, which achieved efficient removal.

Oxygen‐Stable Electrochemical CO2 Capture using Redox‐Active Heterocyclic Benzodithiophene Quinone

Electrochemical carbon capture offers a promising alternative to thermal amine technology, which serves as the traditional benchmark method for CO2 capture. Despite its technological maturity, the widespread deployment of thermal amine technologies is hindered by high energy consumption and sorbent degradation. In contrast, electrochemical methods, with their inherently isothermal operation, address these challenges, offering enhanced energy efficiency and robustness. Among emerging strategies, electrochemical carbon capture systems using redox‐active materials such as quinones stand out for their potential to capture CO2.However, their practical application is currently limited by their low stability in the presence of oxygen. We demonstrate that benzodithiophene quinone (BDT‐Q), a heterocyclic quinone, exhibits high stability in electrochemical carbon capture processes with oxygen‐containing feed gas. Conducted in a cyclic flow system with a simulated flue gas mixture containing 13% CO2 and 3.5% O2 for over 100 hours, the process demonstrates high oxygen stability with an electron utilization of 0.83 without significant degradation, indicating a promising approach for real world applications. Our study explores the potential of new heterocyclic quinone compounds in the context of carbon capture technologies.

Oxygen-Stable Electrochemical CO2Capture using Redox-Active Heterocyclic Benzodithiophene Quinone.

Electrochemical carbon capture offers a promising alternative to thermal amine technology, which serves as the traditional benchmark method for CO2capture. Despite its technological maturity, the widespread deployment of thermal amine technologies is hindered by high energy consumption and sorbent degradation. In contrast, electrochemical methods, with their inherently isothermal operation, address these challenges, offering enhanced energy efficiency and robustness. Among emerging strategies, electrochemical carbon capture systems using redox-active materials such as quinones stand out for their potential to capture CO2.However, their practical application is currently limited by their low stability in the presence of oxygen. We demonstrate that benzodithiophene quinone (BDT-Q), a heterocyclic quinone, exhibits high stability in electrochemical carbon capture processes with oxygen-containing feed gas. Conducted in a cyclic flow system with a simulated flue gas mixture containing 13% CO2and 3.5% O2for over 100 hours, the process demonstrates high oxygen stability with an electron utilization of 0.83 without significant degradation, indicating a promising approach for real world applications. Our study explores the potential of new heterocyclic quinone compounds in the context of carbon capture technologies.

Reactive capture of CO2 via amino acid

Reactive capture of carbon dioxide (CO2) offers an electrified pathway to produce renewable carbon monoxide (CO), which can then be upgraded into long-chain hydrocarbons and fuels. Previous reactive capture systems relied on hydroxide- or amine-based capture solutions. However, selectivity for CO remains low (<50%) for hydroxide-based systems and conventional amines are prone to oxygen (O2) degradation. Here, we develop a reactive capture strategy using potassium glycinate (K-GLY), an amino acid salt (AAS) capture solution applicable to O2-rich CO2-lean conditions. By employing a single-atom catalyst, engineering the capture solution, and elevating the operating temperature and pressure, we increase the availability of dissolved in-situ CO2 and achieve CO production with 64% Faradaic efficiency (FE) at 50 mA cm−2. We report a measured CO energy efficiency (EE) of 31% and an energy intensity of 40 GJ tCO−1, exceeding the best hydroxide- and amine-based reactive capture reports. The feasibility of the full reactive capture process is demonstrated with both simulated flue gas and direct air input.

Performance analysis of precooling systems for cryogenic carbon capture: A comparative study of theoretical, numerical, and experimental methods

The urgency of addressing climate change has necessitated innovative and practical approaches to reducing greenhouse gas emissions. Cryogenic Carbon Capture (CCC) technology has emerged as a promising solution for capturing CO2 from industrial emissions. This study investigates a simplified design for a precooling system within CCC technology, focusing on optimizing the efficiency and reliability of the system while minimizing energy consumption. The research examines the effects of CO2 concentration in a gas mixture (simulated flue gas, nitrogen and carbon dioxide), cooling bath temperature, and gas mixture flow rate on the performance of heat exchangers in the precooling system. Theoretical, numerical, and experimental analyses were conducted to assess the system's performance. The use of liquid nitrogen at −196 °C in the cooling bath was found unsuitable due to CO2 freezing within the pipes. Instead, a mixture of dry ice and isopropyl alcohol at −78.5 °C proved effective in maintaining consistent temperature and pressure conditions without causing CO2 blockages. Numerical simulations highlighted the importance of optimizing pipe length to balance temperature control and pressure dynamics, with a 140 cm pipe length identified as optimal for heat exchanger design. Experimental results revealed that longer pipes enhance cooling performance due to increased heat exchange surface area, while higher CO2 compositions and flow rates result in higher outlet temperatures and pressures. The study emphasizes the need for further research and simulation work to refine heat exchanger designs for industrial applications, aiming to develop systems that maximize cooling efficiency while ensuring reliable operation.

Hollow tubular MnOx prepared by flame annealing with cotton fiber as sacrificial template and its applications for Hg0 adsorption in flue gas

The mass discharge of mercury from coal-fired power plant has caused great harm, abating mercury emissions is of preoccupation for protecting public environmental safety and human health. Metal oxides are often used for Hg0 removal in the flue gas. In this paper, a hollow tubular MnOx(MnCot) was successfully prepared by rapid flame annealing using cotton fiber as a sacrificial template. The MnCot were then well characterized and tested for its capability for Hg0 removal in flue gas. The results indicate that the flame assisted synthesis method for rapidly prototyping metal oxides with typical structures is achievable. The hollow tubular structure of the cotton fiber is well reprinted with good crystallization of Mn3O4. The inner diameter of the hollow tubular MnCot is about 10 μm, and the thickness of the tube is about 1 μm. The Hg0 removal efficiency on MnCot can be maintained as high as 90 % under simulated flue gas atmosphere below 240°C. O2 and NO have a positive effect on the Hg0 removal, which can act as the fresh active sits thus enhancing its capability for Hg0 removal. However, the presence of SO2 will result in the surface sulfation on MnCot, thus deteriorating its capability for Hg0 removal. Further, the competitive adsorption between SO2 and Hg0 on the material will also weaken its capability for Hg0 removal. The hollow tubular MnOx rapidly prepared by one-step flame annealing has a good industrial application potential for Hg0 removal in coal-fired flue gas.

Deactivation effect of elemental mercury oxidation over a V2O5-WO3/TiO2 catalyst by Pb in simulated coal-fired flue gas

Lead (Pb) is a typical heavy metal in the flue gas of coal-fired power plants, which can cause the deactivation of SCR catalysts. In this study, Pb-doped vanadium-based catalysts were prepared and investigated for the deactivation effect and mechanism of elemental Hg oxidation caused by Pb. The results showed that doping Pb on vanadium-based catalysts led to severe deactivation, which was more pronounced with increased Pb content. Further investigation illustrated that the introduction of Pb not only weakened the BET surface properties of vanadium-based catalysts but also increased the aggregation of surface species on the catalysts. After Pb introduction, the adsorption capacity toward elemental Hg, proportion of highly oxidized V5+, and surface Oβ ratio significantly decreased severely weakening the activity of the catalyst. In addition, we demonstrated that the reaction between Pb and active VO/V−OH groups of the catalyst formed inactive V−O−Pb species, which was the direct cause of catalyst deactivation.