Hg0 Removal Efficiency Research Articles

Co3O4 nanotubes embedded in the interlayer of GO nanosheets for efficient Hg0 removal from coal flue gas

Adsorption is an efficient and practical method to remove Hg0 from coal flue gas. Surface active oxygen of the sorbents can adsorb Hg0 forming HgO which becomes the essential factor for efficient Hg0 removal. In this study, Co3O4 nanotubes were embedded into the interlayer of GO nanosheets to prepare a composite material 3D. SEM and TEM results show that GO gives a high dispersion of Co3O4 nanotubes, which is beneficial to the adsorption and activation of O2 on Co3O4 nanotubes surface. XPS results show that when the mass ratio of GO to Co3O4 was 1:2 (Go-Co3O4-1–2), the sorbent had the best Oβ/OT ratio and the best redox capacity. It means that the oxygen-containing functional groups on the GO surface can provide more active sites for the Co3O4 nanotubes to capture and activate O2 into chemisorbed oxygen. Furthermore, GO has a fast electron transfer which can improve the electron shift in the reaction of Hg0 + O2 → HgO. As a result, the Hg0 removal efficiency of GO-Co3O4-1–2 reached 94.67% under 180,000 h−1 at 250 °C, and showed a good stability. The Hg0 removal mechanism and regeneration mechanism were deduced based on the XPS results of the fresh, used and regenerated sorbent.

Magnetic rice-straw-derived biochar for adsorptive removal of Hg(II) from aqueous solution: Optimization using response surface methodology

Magnetic rice-straw-derived biochar (MRBC) composites were synthesized by binding magnetite to the surface of the biochar for the highly efficient removal of Hg(II) from an aqueous solution. The maximum adsorption capacity of the adsorbent was 85.8 mg/g, which is much higher than those of other previously reported adsorbents for Hg(II) removal. The experimental data exhibited a good fit with a pseudo-second-order kinetic model, and the adsorption behavior followed the Langmuir isotherm. A thermodynamic study indicated that Hg(II) adsorption was spontaneous and endothermic. The individual effects and interactions of three key parameters such as initial Hg(II) concentration, adsorbent dosage, and pH were investigated by the Box–Behnken design of response surface methodology. The maximum removal efficiency of Hg(II) was 94.91% under an optimal condition of pH 3.9, an initial Hg(II) concentration of 14.3 mg/L, and an adsorbent dosage of 4.5 g/L. In the adsorption–desorption investigation, the MRBC was reusable for five adsorption–desorption cycles. The synthesized MRBC is a simple and inexpensive absorbent that can be readily isolated from a solution using a magnet after Hg(II) remediation.

Mercury removal over Ce-doped LaCoO3 supported on CeO2 at low temperatures from coal combustion flue gas

Mercury has a significant impact on environment and is mainly derived from coal-fired power plant. Herein, we report a potential route for efficient removal of Hg0 via oxidation reactions using Ce-doped LaCoO3 supported on CeO2 catalyst. Catalyst characterization results proved that Ce can successfully substitute a desired part of Co into the LaCoO3 crystal lattice via a sol–gel method. The Hg0 removal experiments suggest that Hg0 removal efficiency decreased in the order of La0.875Ce0.125CoO3/CeO2 > La0.875Ce0.125CoO3 > LaCoO3. The presence of O2 provided more active oxygen and resulted in approaching 100% Hg0 removal efficiency. Introducing H2O and sole SO2 would significantly reduce the Hg0 removal efficiency as a result of competitive adsorption on the actives sites of the catalyst. On the other hand, SO2 could reacted with Hg0 in the presence of O2 and thereby recover the high Hg0 removal efficiency and the La0.875Ce0.125CoO3/CeO2 catalyst presented a good performance towards sulfur resistance. Furthermore, the catalyst still exhibited a high Hg0 removal efficiency performance after five times consecutive recycles.

Oxidative absorption of elemental mercury in combustion flue gas using biochar-activated peroxydisulfate system

In the article, rice straw biochar was applied to activate peroxydisulfate to induce ·OH and SO4−· to oxidize Hg0 in flue gas. The oxidative absorption mechanism of gaseous Hg0 in this designed system was explored. The main technological variables affecting Hg0 oxidative absorption, and the yields of products and free radicals were also studied. Research indicates that Hg0 is mainly removed by SO4−· oxidation and ·OH oxidation. SO4−· is the first important free radical for oxidizing Hg0, and ·OH is the second important free radical for oxidizing Hg0. Hg0 is mainly oxidized to bivalent mercury (Hg2+) in spent solution by the developed absorption system. Peroxydisulfate direct oxidation and biochar catalytic oxidation are also two other Hg0 removal paths, but they only play minor supplementary roles in the Hg0 removal. Hg0 removal efficiency is improved first and then decreased by increasing peroxydisulfate concentrations or rice straw biochar concentrations. Increasing reaction temperature improves the Hg0 removal. Hg0 removal efficiency reduces with higher pH values and Hg0 concentrations. The maximum removal efficiency of Hg0 is up to 96.9% based on the best tested conditions.

Simultaneous removal of SO2, NO and Hg0 using porous carbon/heat-coactivated persulfate system

A novel simultaneous removal technique of SO2, NO, and Hg0 using porous carbon/heat-coactivated persulfate (PS) system was proposed. A series of experiments and theoretical analysis were conducted to explore simultaneous removal process of Hg0, SO2, and NO. Study demonstrates that the developed porous carbon/heat-coactivated PS system gains larger free radical yield and higher pollutants simultaneous removal efficiency than other comparison systems, which are associated with the synergism between porous carbon and heat. High temperature plays a vital role in this co-activation system. Both SO4−· and ·OH play an important role in NO and Hg0 removal, but ·OH is more important for NO removal while SO4−· is more important for Hg0 removal. Both NO and Hg0 removal processes meet pseudo-first-order rapid reaction kinetics, and their removal processes are controlled by mass transfer. Removal efficiencies of NO and Hg0 are increased first and then are decreased with increasing PS concentration, temperature and porous carbon concentration. Increasing pH and concentrations of SO2, NO and Hg0 reduce the NO and Hg0 removal efficiencies. The highest simultaneous removal efficiency of Hg0, SO2, and NO is up to 98.4% for Hg0, 100% for SO2, and 89.3% for NO under an optimized test condition.

Self-template synthesis of CuCo2O4 nanosheet-based nanotube sorbent for efficient Hg0 removal

Adsorption method is an effective way to remove Hg0 from flue gas, and the morphology and active site of sorbents seriously affect the Hg0 removal efficiency. The hierarchical porous nanosheet-based nanotube structure can effectively reduce the mass transfer resistance and provide more active sites. Inspired by this, the organic-inorganic hybrid nanowires of Co-aspartic acid was used as the template, which can hydrolyze in water-alcohol mixed solution and coordinate with Cu2+ based on Kirkendall effect to prepare nanosheet-based nanotube of CuCo2O4 sorbents. By changing the ratio of water to alcohol, the hydrolysis rate of Co-aspartic acid nanowires will be changed resulting in different physicochemical properties for CuCo2O4 sorbents. Characterization results show that when the ratio is 1:2, the sorbent (CuCo2O4-1-2) has the best hierarchical porous nanosheet-based nanotube structure and the best redox properties. CuCo2O4-1-2, which has the widest reaction temperature window, has a high Hg0 removal efficiency of 89 % under a high GHSV of 180 000 h−1 at 250 °C and a good poisoning resistance and stability. The straight nanotube can effectively reduce the gas transfer mass resistance, and the mesoporous nanosheets structure on its surface provide more active sites for the reaction, which improves the ability of CuCo2O4-1-2 sorbent to capture and activate O2. Meanwhile, DFT calculation shows Cu-Co on the surface of CuCo2O4 is the main active site because the bond length of OO can be effectively lengthened when O2 is adsorbed on the Cu-Co site.

Granulation of Mn-based perovskite adsorbent for cyclic Hg0 capture from coal combustion flue gas

Circulating adsorbents in a fluidized bed integrating elemental mercury (Hg0) adsorption and oxidized mercury decomposition/desorption processes could simultaneously achieve adsorbents recycling and mercury recovery during the flue gas mercury removal. The granulation of adsorbent powder is essential to reduce elutriation the looping system. Herein, powdery La0.8Ce0.2MnO3 perovskite adsorbent, which has been demonstrated to be highly efficient for Hg0 removal, was moulded into 0.8–1 mm pellets by an extrusion-spheronization method. Meanwhile, microcrystalline cellulose (MC) was used as pore-creating template to constructing porous pellets. The results show that the La0.8Ce0.2MnO3 pellets with 20 % MC added during the pelleting process (LCMO-MC) exhibited 90 % Hg0 removal efficiency under a gaseous hourly space velocity (GHSV) of 380,000 h−1, which was comparable to that over the corresponding powdery adsorbent. The LCMO-MC performed well in Hg0 removal at a wide temperature window from 50 to 200 °C. SO2 and H2O displayed slight interference in Hg0 removal, while O2 and NO enhanced Hg0 removal over LCMO-MC. During six adsorption-decomposition/desorption cycles, the LCMO-MC presented outstanding cyclic durability and about 97 % Hg0 removal efficiency was achieved with a GHSV of 50,000 h−1. The excellent Hg0 removal capacity of LCMO-MC was ascribed to the existence of abundant pore channels for Hg0 diffusion, which in-situ retained during the burning of pore-creating templates at high temperature and newly formed accompanying with the burning gas release. These results demonstrate that the template (i.e., MC) assisted extrusion-spheronization approach is promising to mould adsorbent pellets for Hg0 removal in a fluidized-bed system, which could simultaneously realize adsorbent recycling and mercury recovery.

FeNi3 foam as cathode catalyst in electrocatalytic peroxydisulfate system for enhanced Hg0 removal from simulated flue gas

The feasibility of elemental mercury (Hg0) removal from simulated flue gas in electrocatalytic peroxydisulfate (PDS) system employing FeNi3 foam as cathode catalyst was studied for the first time. The electrocatalytic (EC) performance of FeNi3 foam activating PDS process was evaluated to remove Hg0 using Pt anode, FeNi3 cathode, and Na2SO4 electrolyte at room temperature. The results showed that the FeNi3 foam/PDS/EC system was superior to the other removal processes. According to the influence of experimental parameters, it was found that about 94% of Hg0 was removed within 20 min under the conditions of voltage = 2 V, PDS = 1 mM, Na2SO4 = 0.05 M. Theoretical calculations showed that the Ni atom of the FeNi3 cluster would improve its reactivity. The chemical adsorption and hybridization between PDS and FeNi3 had contributed to an efficient production of SO4•− free radical. The high removal efficiency of Hg0 was due to the following assistances: (i) the O2 gas adsorbed on the FeNi3 foam cathode surface was able to generate radicals •O2– and •OH by single electron reduction reaction, (ii) FeNi3 foam catalyst could afford Fe(II) and Ni(II) ions via two electron transfer, activating PDS to produce SO4•−, and (iii) the copresence of Fe and Ni was useful to accelerate the ion cycles of Fe(III)/Fe(II) and Ni(II)/Ni(I), which played a crucial role in FeNi3 foam/PDS/EC system. The novel proposed FeNi3 foam cathode electro-catalyzing PDS system provided a promising prospect in the pollutant control field of Hg0 removal.

Efficient removal of Hg0 in flue gas using a novel Sn-based porphyrin polymer

A Sn-based porphyrin polymer (TAPP(Sn)-FAC) synthesized in a mild condition was introduced for the Hg0 removal in flue gas. The properties characterization of materials revealed the two-dimensional sheet structure, an amorphous structure and high stability of TAPP(Sn)-FAC, and Sn was successfully incorporated into TAPP-FAC in the form of SnN. The removal performance of Hg0 under different conditions was investigated using a lab-scale fixed-bed reactor. TAPP(Sn)-FAC presented an excellent Hg0 removal efficiency from 100 °C to 250 °C, which can reach 8 mg/g of Hg0 capture capacity at 100 °C for 300 min. Besides, TAPP(Sn)-FAC had a strong sulfur and water resistance, and the presence of NO and O2 had a facilitating effect for Hg0 removal. Moreover, the existence of Sn can enhance the Hg0 adsorption and oxidation capacity of TAPP(Sn)-FAC by promoting the electron transfer process. Furthermore, TAPP(Sn)-FAC presented an excellent chemical stability, which was a promising material in the Hg0 removal in flue gas.

Simultaneous oxidation absorption of NO and Hg0 using biomass carbon-activated Oxone system under synergism of high temperature

Compared with the heterogeneous activation technology activated by transition metal oxides, the biomass carbon-activated Oxone technology receives extensive attention because it does not produce metal ion leakage (no secondary pollution). Here a biomass carbon-activated Oxone system under synergism of high temperature was designed to achieve simultaneous oxidation absorption of NO and Hg0 from simulated flue gas. The feasibility, mechanism, products and main technical influencing factors of NO and Hg0 simultaneous removal using this system were explored. The developed removal technique gains a high simultaneous removal efficiency of NO and Hg0 (respectively reaching 91.5% and 98.8%). Based on removal efficiency comparison, free radicals determination and sacrificial agent experiment, hydroxyl radical is proved to be a dominant oxidant for NO removal, and sulfate radical is the second important oxidant for NO removal. Sulfate radical is found to be a dominant oxidant for Hg0 removal, and hydroxyl radical is the second important oxidant for Hg0 removal. Synergistic effect of high temperature and biomass carbon plays a vital role in efficient removal of NO and Hg0. Increasing Oxone concentration, temperature and biomass carbon concentration enhance simultaneous oxidation absorption process of NO and Hg0. However, increasing pH and concentrations of NO and Hg0 reduces simultaneous removal efficiency of NO and Hg0. The main products of NO and Hg0 simultaneous oxidation absorption are NO3– and Hg2+, which can be recycled through the proposed product post-treatment route.

Insight into the sulfur resistance of OMS-2 modified with iron for mercury oxidation

To improve the sulfur resistance of manganese oxide octahedral molecular sieve (OMS-2) for Hg0 oxidation, OMS-2 modified by iron (Fex-OMS-2) is prepared through hydrothermal synthesis method in this study, and their Hg0 removal performance and sulfur resistance were tested in simulate flue gas. Hg0 removal efficiency of Fe0.05-OMS-2 can reach 98 % at 150 °C. Its mercury removal efficiency remains 89.2 % even in the presence of 1500 ppm SO2, while the value of OMS-2 under the same condition is only 54 %. Characterization results show that Fe0.05-OMS-2 has spinel structure with Fe2O3 wrapped on the catalyst surface which is (Mn0.983Fe0.017)2O3. Its active components both contain iron oxide and manganese oxide, which forms a double active center. Iron oxide on the catalyst surface can compete with manganese oxide for SO2 adsorption and further forms FeSO4, thus, inhibiting the sulfation of active manganese oxide and improving its sulfur resistance. Additionally, Fe0.05-OMS-2 exhibit strong water resistance, and Hg0 removal efficiency is nearly no change after the addition of 8 % H2O in the simulated flue gas.

Using the composite material of GO and g-C3N4 nanosheets as substrate to in-situ grow Co3O4 nanosheets for efficient Hg0 removal

Chemisorption is an effective method to remove Hg0 from coal-fired flue gas. During this process, Hg0 will convert to Hg2+ and be solidified on sorbent surface. The number of adsorption sites and the electron transfer between Hg0 and sorbents play an important role in the removal process. In the present work, GO with a rapid electron transfer was compounded with NS-g-C3N4 to improve the electron donating ability of NS-g-C3N4. After that, Co3O4 nanosheets were grown in-situ in the interlayer space of GO and NS-g-C3N4 composites. A series of sorbents were successfully synthesized by changing GO concentration. SEM and TEM results show that the corresponding Co3O4/GCN (GCN denote the GO and NS-g-C3N4 composites) sorbent has better Co3O4 nanosheet dispersibility when GO concentration is 5 mg/mL. This results in a large amount of chemisorbed oxygen, which is favor to the oxidation of Hg0 to HgO. In addition, XPS results show that the interaction between Co3O4 and GCN give a rapid electrons transfer from GCN to Co3O4, thus improving the activation of gaseous oxygen. Therefore, Co3O4/GCN-5 has excellent Hg0 removal efficiency of about 95 % at 200 °C and high stability under different flue gas conditions. A probable reaction path way was deduced by the results of XPS and Hg0 adsorption–desorption experiment.

Revealing insights into the correlations between structure and performance of CrOx monometallic oxide for Hg0 capture

This study explored the impacts of the synthesis methods on the Hg0 elimination ability of CrOx adsorbents. In the sample series, the adsorbent prepared using the sol-gel method (labeled as Cr(S)) presented the best Hg0 capture performance; its Hg0 removal efficiency stayed above 88% at 150 and 200 °C and even rose to ∼97% at 250 °C in the entire 5-h Hg0 capture process. The presence of bountiful surface acid sites aided the sufficient adsorption of Hg0 and an enhancement in the oxidizability primarily accelerated the subsequent Hg0 oxidation step, which constituted the central reason for the satisfactory Hg0 capture capability of Cr(S). The Mars-Maessen mechanism assisted in understanding the Hg0 capture process over Cr(S), in which chemisorption was dominant with Cr6+ and Oα serving as the active sites and HgO formed as the final oxidation product.

Copper selenide sensitized low-cost porous coordination polymers towards efficient capture trace gaseous elemental mercury

Mercury, as a highly toxic atmospheric pollutant, poses serious hazards to global health and ecosystems. Developing low-cost sorbents with simultaneous fast capture rate and large uptake capacity to reduce elemental mercury (Hg0) emissions from industrial flue gas remains a formidable challenge. Herein, a rationally designed surfactant-assisted method was developed to construct copper selenide (CuSe) sensitized porous coordination polymers (CAU-10-H) as an efficient Hg remediator. The CuSe/CAU-10-H (0.8NC-CAU) exhibits superior near-100 % gaseous Hg0 removal efficiency over a wide temperature range (30–120 °C), implying its adaptability under different implementations. The equilibrium Hg0 adsorption capacity and initial Hg0 uptake rate of 0.8NC-CAU are 748.09 mg·g−1 and 63.21 μg·g−1·min−1, respectively, surpassing that of conventional sorbents and comparable to the benchmark materials. Furthermore, 0.8NC-CAU can adapt to harsh conditions with different flue gas impurities containing SO2, NO, and H2O to maintain high selectivity and stability, which is advantageous for real-world applications. Density functional theory (DFT) reveals that unsaturated selenium ligands as electron acceptors are critical affinity sites for facilitating Hg0 capture, resulting in stable HgSe species. More importantly, the facile preparation, prominent uptake capacity, and rapid capture rate of the 0.8NC-CAU material make it cost-effective. This work proposes a potential trap for Hg0 capture from industrial flue gas and facilitates the development of hybrid-functionalized materials for environmental remediation.

Engineering single-atom Pd sites in ZIF-derived porous Co3O4 for enhanced elementary mercury removal

Engineering metal-based nanoarchitectures and their atomic-scale arrangement is a promising avenue for enhanced mercury adsorbent activities. Interactions between metal single atoms and substrates result in regulated transitions between distinct reaction processes that boost mercury adsorption activity. Herein, a novel sorbent of porous Co3O4 with Palladium atomic dispersed was successfully prepared by one-step pyrolysis of zeolitic imidazolate framework 67 (ZIF-67) precursors. Via engineering single Pd atoms into ZIF-derived Co3O4 (Pd1/Co3O4-ZIF), the strong metal-support interaction (SMSI) activated the reducibility of Co3+ in porous Co3O4 to efficiently adsorb and oxidize Hg0, enhancing its mercury removal efficiency. Specifically, Pd1/Co3O4-ZIF exhibited superior sorption performance for Hg0 over a broad range of temperatures (30–350 °C) and high gaseous hourly space velocity (about 555,500 hr−1) with the average Hg0 removal efficiency higher than 98%. The strategy of constructing atomic active sites on the surface of porous metal-oxide to convert adsorbed Hg0 into HgO is a promising approach to solve the problem that Hg0 in flue gas is challenging to remove. Density functional theory (DFT) calculation further proved that the existence of a single Pd site on the surface of Co3O4 significantly reduced the energy barrier of Hg0 to HgO at the atomic level. This work contributed to a thorough comprehension of the structural and adsorption properties of the ZIF-derived Co3O4 sorbent engineering with a single atom and enabled the efficient capture of elemental mercury in flue gas by such ZIF-derived sorbent.

Removal of mercury from cyanide leach solution using potassium amyl xanthate (PAX)

The dissolution of mercury during cyanide leaching of Hg-containing gold ores and amalgamation tailings cause many environmental, health and operational problems. For this reason, mercury removal is a very important factor in the economic and environmental selection of the separation method.In this study, the use of potassium amyl xanthate (PAX) as precipitation reagents in the removal of mercury-cyanide complexes from synthetic solutions containing gold, silver and mercury has been investigated. The effect of reaction time, PAX:Hg molar ratio, pH, temperature, CN concentration and Cu concentration on the precipitation of mercury was explored using synthetic mercury-cyanide solutions. Detailed characterization of precipitates was performed using SEM EDS, XRD, FT-IR and particle size analysis.The results of this study illustrate that the precipitant dosage, initial concentrations, pH and temperature were quite effective on the Hg removal efficiency. The best Hg removal efficiency was obtained of 99.2 % at 44.7 °C. The Hg concentration was reduced from 10000 ppb to 72 ppb. As a result of characterization tests, it has been determined that highly stable metacinnabar (β-HgS) is formed as precipitate. The findings showed that PAX is an effective reagent for the selective precipitation of mercury from cyanide leaching solutions.

New insights into the morphological effects of MnOx-CeOx binary mixed oxides on Hg0 capture

In this study, the morphological effects of MnOx-CeOx adsorbents on their Hg0 elimination performance were investigated. The sample with a virgin nanorod microtopography performed significantly better than the nanocube-containing counterparts; in the whole temperature range investigated, a Hg0 removal efficiency of ∼97% was maintained. The microstructure of virgin nanorods possessed a high specific surface area, meaning that the interactions between Hg0 and adsorbent surface active sites would be encouraged. Furthermore, the strong acidity and oxidizability would facilitate the adsorption of Hg0 and the oxidation of the adsorbed Hg0 to HgO, which finally contributed to a superior Hg0 capture ability. During the entire Hg0 capture cycles, only Mn4+ and chemisorbed oxygen operated as the active sites in oxidizing Hg0 to HgO over the nanorod-containing MnOx-CeOx samples, whereas Ce4+ joined the active species group to oxidize Hg0 for the MnOx-CeOx with a virgin nanocube, despite its limited activity. Such knowledge demonstrated that morphology control of the adsorbents at the nanometer level could significantly increase their activity.

Revealing Insights into the Mechanism of Hg0 Removal over MnO2 Hollow Sphere Adsorbents: Effect of Calcination Temperatures

In this study, MnO2 hollow spherical adsorbents were synthesized using the template approach, and the impacts of calcination temperatures on their physicochemical parameters and Hg0 removal ability were investigated. The adsorbent calcined at 300 °C (labeled as Mn300) demonstrated the highest performance; at 200 °C, the Hg0 removal efficiency reached over 90%. The presence of surface acid sites promoted the physisorption of Hg0 and compensated for the relatively weak oxidative ability, which made much of the Hg0 susceptible to capture on the adsorbent surface and consequently explained Mn300’s superior Hg0 capture capacity. The Mars–Maessen mechanism helped to understand the Hg0 capture pathways over Mn300, with Mn4+ and chemisorbed oxygen serving as the active species to oxidize Hg0 to HgO. Finally, Mn300 demonstrated reasonable recyclability and a rather weak gas-component adaptability, indicating that additional modification is required to improve the practical use of the adsorbent.

Layered porous carbon material derived from food residues and its application for elemental mercury adsorption in flue gas

Abating mercury emissions from coal-fired industries is of preoccupation for protecting public environmental safety and human health. Affordable and high efficiency sorbents development for Hg0 adsorption in coal-fired industry is of practical significance for commercial applications. In this work, we report a layered porous carbon (LPC) material derived from food residues for Hg0 removal in coal-fired flue gas. The LPC is with significant high surface area of 2925 m2/g and mesoporous pore structures. Micro-mesoporous ranging from 0.4 nm to 5 nm are commonly found in the LPC, which can help promote mass diffusions thus enhancing Hg0 adsorption capability. Excellent Hg0 removal performance can be observed in simulated flue gas in 150℃ with the Hg0 removal efficiency reaching to 100 %, and it remains around 100 % within 5 successive adsorption and desorption processes without any loss. Both O2 and NO contribute significantly for the Hg0 oxidization and adsorption on LPC, and the presence of NO can greatly improve sulfur resistance for LPC. The LPC shows a rapid and efficient Hg0 adsorption capability once exposing in the Hg0 containing flue gas, and the maximum Hg0 adsorption capacity is estimated to be as high as 571 mg/g, which is much higher than other reported carbon base sorbents. The LPC derived from food residues has an industrial application potential for Hg0 removal in flue gas with the advantages of low cost and excellent adsorption performances.

Perovskite surface regulation to enhance the catalytic performances on SCR and Hg0 oxidation at low temperature

LaMnO3 is one of the most common Mn-based perovskites which has been studied as a low-temperature catalyst for NOx reduction. However, the Hg0 oxidation performance of LaMnO3 is not ideal. An acid treatment method was adopted to regulate the LaMnO3 surface to expose more active sites. The obtained MnO2/ LaMnO3 sample showed enhanced SCR and Hg0 oxidation performances. The NO conversion rate and Hg0 removal efficiency of MnO2/ LaMnO3 could be over 85% in the temperature range of 150−250 °C. The results suggested that the catalyst might be used to remove NO and Hg0 simultaneously at low temperature in coal-fired flue gas.