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Many SCR catalysts without V species are developed and used for the NO abatement. The content of Ca in the real flue gas will result in the deactivation of catalysts. In this work, the effect of Ca(OH)2 on the denitration performance of the Fe–Ce/TiO2 catalyst for SCR reaction was explored. The BET, XRD, XPS, NH3-TPD, Py-IR, UV–Vis DRS, H2-TPR, and SEM–EDS mapping techniques were used to characterize the evolution of active species and the surface properties over the studied catalysts. The gained results demonstrate that the Ca(OH)2 results in serious deactivation of Fe–Ce/TiO2 catalyst for NH3-SCR reaction and the degree of deactivation is closely related to the loading of Ca(OH)2. Such serious deactivation caused by Ca(OH)2 is attributed to the smaller surface area, the declined redox ability and surface acidity, the lower content of Ce3+ and Fe3+, as well as the less surface adsorbed oxygen species. Moreover, the addition of Ca(OH)2 leads to poor dispersion of Ce and Fe species over the catalyst surface, which may also be responsible for the fall of the catalytic performance of the catalyst.

The Fe–Ce/Ti catalysts with different molar ratios of Fe and Ce were synthesized by the precipitation method and impregnation method and used for the SCR reaction. BET, XRD, NH3-TPD, XPS, H2-TPR, UV–Vis, TEM, SEM–EDS mapping techniques were performed to explore the physicochemical properties of catalysts synthesized by different methods. As a result, the catalysts synthesized by precipitation method yields higher catalytic activity than that of the catalysts prepared by the impregnation method. The precipitated catalysts possess larger specific surface areas, higher ratios of Ce3+/Ce4+ and Fe3+/Fe2+ and more surface chemisorbed oxygen, as well as the enhanced surface acid sites and redox ability. Besides these, it holds a high dispersion of active species and more uniform smaller nanoparticles. All mentioned above will result in a higher catalytic performance of catalysts.

The catalytic NO removal efficiencies of MnFeOx/SiO2 catalysts with different Fe/Si were compared and studied. The reaction pathway analysis of NH3-SCR on the surface of MnFeOx/SiO2 catalyst was performed based on DFT calculations. The experimental results of catalytic activity show that the addition of an appropriate amount of iron oxide has significant improvement for the NO conversion from 240 °C to 330 °C and the N2 selectivity from 150 °C to 330 °C. The XRD test also shows that the addition of iron oxide can greatly improve the dispersion of MnO2. In addition, DFT calculations indicate that the main process of N2 formation is the NH2NO decomposition and N-NO reaction. The N-NO reaction to form N2 is a unique reaction pathway possessed by MnFeOx/SiO2, which is the main reason for the high NO conversion and good N2 selectivity of MnFeOx/SiO2 catalyst and shows good synergy between manganese oxide and iron oxide.

Based on the density functional theory, the adsorption processes of NH3, and NO and O2 on the Mn active sites of MnOx/SiO2 β-cristobalite (101) surface were simulated. The results show that NH3, NO and O2 can be effectively adsorbed on the Mn active sites of both MnO2/SiO2 β-cristobalite (101) and Mn2O3/SiO2 β-cristobalite (101) surface. The adsorption characteristics of the two catalysts are different. The adsorption energy of NH3 molecule on the MnO2/SiO2 β-cristobalite (101) surface is much higher than that on the Mn active sites of Mn2O3/SiO2 β-cristobalite (101) surface. The NO molecule and the O2 molecule are a little easier to be adsorbed on the Mn active sites of Mn2O3/SiO2 β-cristobalite (101) surface. The large difference of NH3 adsorption energy between the two catalysts becomes one of the main reasons why MnO2/SiO2 has better catalytic activity than Mn2O3/SiO2. Furthermore, the high adsorption energy of NH3 on MnO2/SiO2 surface proves that SiO2 is an excellent carrier and MnO2/SiO2 catalyst is an outstanding NH3-SCR catalyst at low temperature.

Mn–Ce/TiO2 catalysts were co-pretreated with SO2 and Ca and applied for the selective catalytic reduction (SCR) of NO with ammonia. The effect of co-pretreatment of SO2 and Ca on the physicochemical properties of catalysts was investigated by BET, XRD, XPS, NH3-TPD, H2-TPR, and UV–Vis techniques. The results show the co-pretreatment of SO2 and Ca greatly influences the physicochemical properties of catalysts such as texture characteristics, surface acidity and redox ability, amounts of active species and surface OH group, and therefore affects the catalytic activity of catalysts. The Mn–Ce–Ti(S–OH) catalyst co-pretreated with SO2 and Ca(OH)2 exhibits better catalytic activity than Mn–Ce–Ti(S–Cl) catalyst co-pretreated with SO2 and CaCl2. The Mn–Ce–Ti(S–OH) catalyst possesses larger specific surface area, higher concentrations of surface active species and surface chemisorbed oxygen, better surface acidity and redox ability, which may contribute to the accelerated catalytic activity.

The low-temperature catalytic NO removal efficiencies of catalysts with two different manganese precursors, manganese acetate (αMA catalyst) and manganese nitrate (αMN catalyst), were compared and studied. The NH3-SCR of NO tests using these catalysts were carried out in a self-made reaction device to measure the catalytic activity of the catalysts. Moreover, the reaction pathway analysis of NH3-SCR of NO on the surface of MnO2/SiO2 catalyst and Mn2O3/SiO2 catalyst were performed based on DFT calculations individually. The experimental results show that the NO conversion of αMN catalyst is higher than the αMA catalyst at low temperature (

The different forms of Ca (CaCl2 and Ca(OH)2) poisoned manganese and cerium oxides supported on TiO2 catalysts were prepared by impregnation method and used for selective catalytic reduction (SCR) of NO with NH3. The Ca poisoning effects were investigated by many characterization methods including N2 adsorption/desorption, X-ray diffraction, X-ray photoelectron spectroscopy, H2-temperature programmed reduction and NH3-temperature programmed desorption techniques. The results showed that the addition of Ca led to greatly decrease of catalytic activity of catalysts and the catalytic activity was ranked in the order: CaCl2 poisoned catalyst

Mn-Ce-Ti catalysts were prepared by different precursors (including manganese nitrate, manganese acetate, and manganese chloride) and used for selective catalytic reduction (SCR) of NO with ammonia. The relationships among the structure, physicochemical properties, and catalytic activity were explored by N2 adsorption/desorption, X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), NH3-temperature programmed desorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), scanning electron microprobe (SEM) and energy dispersive spectroscopy (EDS) techniques. The results show that the different Mn precursors play important roles in the catalytic activity. The Mn-Ce-Ti(N) catalyst synthesized by manganese nitrate precursor exhibits the best catalytic activity, while the Mn-Ce-Ti(C) and Mn-Ce-Ti(Cl) catalyst prepared by manganese acetate and manganese chloride, respectively, exhibit relatively low catalytic activity. The manganese nitrate precursor could promote the specific surface area and redox ability, enhance the amounts of Bronsted and Lewis acid sites, and enrich the surface active species such as Mn4+, Ce3+ and surface chemisorbed oxygen of the catalyst, all of which will contribute to the SCR performance. Moreover, the Mn-Ce-Ti(N) catalyst possesses highly dispersed and uniform surface active species, which will result in the optimal physicochemical properties and superior catalytic performance.

The adsorption process is the first step and a crucial step in the SCR NOx removal. The adsorption characteristics of NH3, NOx on the surface of the catalyst is very important on the understanding the catalytic mechanism of low-temperature catalysts. In this paper, therefore, the adsorption of NH3, NOx and some other small molecules on the surface of the nano-γFe2O3 was studied by using the first principle and density functional theory (DFT). Particularly, the adsorption processes, in which the NH3 and NOx molecules were adsorbed at different active sites of the nano-γFe2O3 catalyst surface, were evaluated and analyzed. The computational results show that octahedral Fe cation of nano-γFe2O3 is the most active site and many kinds of molecules can be adsorbed to the octahedral Fe cation. On the adsorption of NH3, the adsorption energy of Fe N configuration is large and the configuration is stable. When O-defects are present on the surface, the adsorption energy of Fe N configuration will be promoted. On the NOx adsorption process, the adsorption products are more complicated. It can be adsorbed on both the perfect surface and the O-defective surface to form many products. The H2O and N2 can also be adsorbed on the surface of nano-γFe2O3 but the adsorption energy is small. This ensures that H2O and N2 as product can be desorbed from the catalyst surface easily.

Iron-based catalysts have been explored for selective catalytic reduction (SCR) of NO due to environmentally benign characters and good SCR activity. Mn-W-Sb modified siderite catalysts were prepared by impregnation method based on siderite ore, and SCR performance of the catalysts was investigated. The catalysts were analyzed by X-ray diffraction, H

In the present work, fresh and Ca poisoned Fe–Ce/Ti catalysts were prepared and used for the NH3-SCR reaction to investigate the effect of Ca doping on the catalytic activity of catalysts. And these catalysts were characterized by BET, XRD, Raman, UV-vis DRS, XPS, H2-TPR, and NH3-TPD techniques. The obtained results demonstrate that Ca doping could lead to an obvious decrease in the catalytic activity of catalysts. The reasons for this may be due to the smaller specific surface area and pore volume, the decreased ratio of Fe3+/Fe2+ and Ce3+/Ce4+, as well as the reduced redox ability and surface acidity.

In the present work, fresh and Ca poisoned Fe-Ce/Ti catalysts were prepared and used for the NH

Fe–Ce–Al catalysts were synthesized by the co-precipitation method (labeled as Fe–Ce–Al–P), co-impregnation method (Fe–Ce–Al–I), and direct mixing method (Fe–Ce–Al–M), respectively, and used for effective removal of NO. The synthesized catalysts were characterized by many methods including N2 physisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR), high-resolution transmission electron microscopy (HR-TEM), and energy dispersive spectroscopy (EDS) mapping. The results show that the synthesis methods greatly influence the catalytic performance of catalysts. The Fe–Ce–Al–P catalyst prepared by the co-precipitation method yields the highest catalytic performance, while the Fe–Ce–Al–I and Fe–Ce–Al–M catalysts exhibit relatively low catalytic activity. The co-precipitation method can promote the accumulation and dispersion of more surface active species on the catalyst surface, and provide smaller particle size of active species and generate more uniform particle size distribution, while these characteristics can't be obtained by the co-impregnation method and direct mixing method. Moreover, the co-precipitation method could produce the highest surface area and enhanced redox ability and surface acidity of the catalyst, which resulted from the high dispersion and uniform distribution of surface active species. These may be the key factors to the superior catalytic performance of the Fe–Ce–Al–P catalyst.

A series of Fe–Mn catalysts was prepared using different supports (kaolin, diatomite, and alumina) and used for NO abatement via low-temperature NH3-selective catalytic reduction (SCR). The results showed that 12Fe–10Mn/Kaolin (with the concentration of Fe and Mn 12 and 10 wt.%, respectively) exhibited the highest activity, and more than 95.8% NO conversion could be obtained within the wide temperature range of 120–300°C. The properties of the catalysts were characterized by inductively coupled plasma-atomic emission spectrometry (ICP-AES), thermogravimetry (TG), Brunner–Emmet–Teller (BET) measurements, X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), NH3-temperature programmed desorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS), scanning electron microprobe (SEM) and energy dispersive spectroscopy (EDS) techniques. The support effects resulted in significant differences in the components and structures of catalysts. The 12Fe–10Mn/Kaolin catalyst exhibited better dispersion of active species, optimum low-temperature reduction behavior, the largest amount of normalized Bronsted acid sites, and the highest Mn4+/Mn and Fe3+/(Fe3+ + Fe2+), all of which may be major reasons for its superior catalytic activity.

The catalyst is the core of the NH3-SCR NOx removal process, and sulfur resistance is important performance to ensure its stability and efficiency. The γ-Fe2O3 catalyst has great NOx removal efficiency but its sulfur resistance need to be enhanced to meet the needs of development of Fe based catalyst. In this paper, the sulfur resistance of γ-Fe2O3 and Ce/Mn doped catalyst was studied by quantum chemistry and DFT, and this study can reveal the adsorption process of sulfur oxides on the catalyst surface and the decomposition of surface sulfate. The result shows that the SO2 and SO3 prefer to be adsorbed on the Ce sites and let more Fe active sites exposed to participate NH3-SCR process, but the Mn doping hardly works on improving adsorption. Moreover, Ce doping can effectively decrease the activation energy of the decomposition of ammonium sulfate and promote its decomposition on the catalyst surface, but Mn doping almost cannot improve the decomposition of ammonium sulfate on the catalyst surface. Therefore, doping Ce on γ-Fe2O3 catalyst can effectively improve the sulfur resistance of the catalyst, while Mn has little effect.

A certain amount about 3%–5% of Mn doping on γ-Fe2O3 catalyst surface can improve the NO removal catalytic activity. However, the mechanism of Mn doping to improve the de-NOx catalytic activity is still unclear. In this paper, the doping of Mn on γ-Fe2O3(001) surface was optimized, and the adsorption behavior of reactants as well as the reaction pathway were studied by the density functional theory (DFT). The results show that the doping of Mn on γ-Fe2O3(001) surface can lead to the migration of electrons, so as to improve the surface acidity and activity. It can promote the adsorption of NH3 and NO on the surface. On the other hand, the NH3 molecule can be adsorbed and dehydrogenated and the NH2 is the most important product and the process of NH2 formation is the rate determining step. Compared with undoped catalysts, the step is easier to be completed because it has lower energy barrier. The next main step is the reaction between NH2 and NO to produce NH2NO, and then decomposes to N2 and H2O. These steps are also easier to be achieved than undoped catalysts. Therefore, doping of Mn on γ-Fe2O3 catalyst surface can improve the NO removal catalytic activity.

A series of Fe-Mn/Al 2 O 3 catalysts were prepared and studied for low temperature selective catalytic reduction (SCR) of NO with NH 3 in a fixed-bed reactor. The effects of Fe and Mn on NO conversion and the deactivation of the catalysts were studied. N 2 adsorption-desorption, X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, H 2 temperature-programmed reduction, NH 3 temperature-programmed desorption, X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis and Fourier transform infrared spectroscopy were used to characterize the catalysts. The 8Fe-8Mn/Al 2 O 3 catalyst gave 99% of NO conversion at 150 ℃ and more than 92.6% NO conversion was obtained in a wide low temperature range of 90-210 ℃. XPS analysis demonstrated that the Fe 3+ was the main iron valence state on the catalyst surface and the addition of Mn increased the accumulation of Fe on the surface. The higher specific surface area, enhanced dispersion of amorphous Fe and Mn, improved reduction properties and surface acidity, lower binding energy, higher Mn 4+ /Mn 3+ ratio and more adsorbed oxygen species resulted in higher NO conversion for the 8Fe-8Mn/Al 2 O 3 catalyst. In addition, the SCR activity of the 8Fe-8Mn/Al 2 O 3 catalyst was only slightly decreased in the presence of H 2 O and SO 2 , which indicated that the catalyst had better tolerance to H 2 O and SO 2 . The reaction temperature was crucial for the SO 2 resistance of catalyst and the decrease of catalytic activity caused by SO 2 was mainly due to the sulfate salts formed on the catalyst.

The catalysts used in the selective catalytic reduction (SCR) of NOx with NH3 were prepared from γFe2O3 nanoparticles. The NH3-SCR activity measurement was carried out in a fixed bed reactor. The adsorption characteristics of γFe2O3 nano-catalysts to NH3 and NO were studied with in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements. Experimental activity measurement indicated that γFe2O3 used as a SCR de-NOx catalyst exhibited excellent low-temperature SCR de-NOx performance. The DRIFTS measurements showed that there existed both NH4+ bonded to Bronsted acid sites and coordinated NH3 bonded to Lewis acid sites on the catalyst surface. Coordinated NH3 was the main adsorption product. O2 promoted H-abstraction from coordinated NH3 to form NH2 species, as well as O2 greatly enhancing the adsorption of NO on the catalyst surface to form nitrate species and absorbed NO2. Possible reaction paths with the γFe2O3 catalyst were proposed as follows: the SCR process mainly formed NH2 from H-abstraction of coordinated NH3 which reacted with NO to form N2 and H2O at high and medium temperatures. At low temperatures, however, the formation of adsorbed NO2 resulted from NO oxidation by O2 over Fe3+ sites played an important role. NH4NO3 and (NH4+)2NO2 as the key intermediate products reacted with NO to form N2 and H2O at low temperatures.

The doping of Ce on γ-Fe2O3 catalyst surface can improve the NO removal catalytic activity and widen the temperature window of activity. However, the mechanism of promoting the De-NOx activity of γ-Fe2O3 catalyst by Ce doping has not been revealed. In this paper, therefore, the doping of Ce on γ-Fe2O3(001) surface and the adsorption behavior of NH3 and NO as well as the reaction pathway were studied by the density functional theory (DFT). The results show that the doping of Ce on γ-Fe2O3(001) surface can lead to the migration of electrons on the surface of catalyst and cause the dislocation of the surface lattice, so as to improve the surface acid activity. Thus, the Ce doping can increase the adsorbed energy of the modified γ-Fe2O3 catalyst to NO and NH3 and decrease the activation energy barrier of the rate determining step in SCR reaction. Furthermore, the effects of Ce doping will change with the concentration of the Ce doping, and the excellent SCR De-NOx efficiency will be obtained in the optimal doping amount. On the other hand, O2 makes an important effect. Which makes the activation energy barrier of the rate determining step under aerobic condition lower than that under anaerobic conditions, causes the surface active O to react with NO to form NO2 and perform a rapid SCR reaction. The Ce doping can promote the dissociation of O2 on the active cation site and reduce the activation energy barriers of above steps. Accordingly, the doping of Ce on γ-Fe2O3 catalyst surface can improve the SCR process.

The surface reaction process of γFe2O3 catalyst for NOx removal with NH3 was studied by the first principles and density functional theory. The results show that the NH3 molecule is easily adsorbed on the surface of the catalyst, then dehydrogenated to produce NH2, NH and other products, yet most of the products are NH2 since the activation energy barrier from NH2 to NH is high under anaerobic condition. The next main step is that NH2 reacts with gaseous NO to generate NH2NO intermediate products, and then it decomposes to N2 and H2O. The NH3 dehydrogenation is the rate determining step with the activation energy barrier of 88.040 kJ/mol. However, the NH fragment will be formed when oxygen exists since the activation energy barrier from NH2 to NH reduces under aerobic condition. After its formation, the NH fragment will combine with NO to yield NHNO and decomposes to N2 and hydroxyl. In addition, NO2 can be produced on the surface by the absorbed NO reacting with an active O atom, and the NO2 can carry out fast SCR process. Otherwise, the N2O is not easily formed on the surface of γFe2O3 catalyst which means that the catalyst has good selectivity.

Low-temperature De-NO x technology is a new topic in the area of flue gas treatment. This paper presents experimental studies on selective catalytic reduction (SCR) of NO x from synthetic flue gas over iron-based catalysts with ammonia in a fluidized reactor. The iron-based catalysts used in the experiments are particles of Fe 3 0 4 and γ-Fe 2 O 3 , and they are analyzed by X-ray diffraction (XRD) and Mossbauer spectroscopy, before and after reaction. It is observed that the efficiency of De-NO x with γ-Fe 2 O 3 catalyst is high at temperatures from 200―290 °C and the maximum efficiency is seen to exceed 90 % at 250 °C. The effects of magnetic fields on SCR De-NO x using γ-Fe 2 O 3 particles as catalysts are also studied by applying uniform and coaxial magnetic fields to the fluidized bed. The results suggest that SCR De-NO x on γ-Fe 2 O 3 catalyst is fit for operation below 200 °C in the fluidized reactor in conjunction with the effects of magnetic fields.

Selective catalytic reduction (SCR) of NO from simulated flue gas by ammonia with Fe 2 O 3 particles as the catalyst was performed using a magnetically fluidized bed (MFB). X-ray diffraction (XRD) spectroscopy and Brunauer–Emmett–Teller (BET) method were used to analyze Fe 2 O 3 catalyst. Important effects of magnetic fields were observed in the SCR of NO by ammonia over Fe 2 O 3 catalyst. The apparent activation energies of SCR were reduced by external magnetic fields, and the SCR activity of Fe 2 O 3 catalyst was improved with the magnetic fields at low temperatures. Thus the scope of temperature with high efficiency of NO removal was extended from 493–523 K to 453–523 K by magnetic fields. Magnetic fields of 0.01–0.015 T were suggested for NO removal on Fe 2 O 3 catalyst with MFB. The results suggested that the magnetoadsorption of NO onto Fe 2 O 3 surface together with NH 2 and NO free radicals effects induced by the external magnetic fields both acted to improve the rate of SCR of NO on Fe 2 O 3 catalyst. On the other hand, magnetic field effects were also attributed to improved gas–solid contact in MFB.

A magnetically stabilized fluidized bed (MSFB, O 500 mm × 2100 mm) was designed to study dust removal from flue gas. Based on the mechanism of dust removal in a fixed bed, the effects on collection efficiency of magnetic field intensity, ratio of flue gas velocity to minimum fluidization velocity, bed height, and particle average diameter, were investigated. Then feasible methods for MSFB to better remove dust were proposed. Over 95% of dust removal with MSFB can be achieved, when stable fluidization is maintained and when magnetic particles are frequently renewed.

A new semidry flue gas desulfurization (FGD) process is proposed. The process uses a magnetically fluidized bed (MFB) as the reactor in which ferromagnetic particles are fluidized with simulated flue gas under the influence of an external magnetic field. A slurry of lime is continuously sprayed into the reactor by an atomizer fixed at the top of the bed. As a consequence, the desulfurization reaction and slurry drying take place simultaneously in a same reactor. Experiments with a laboratory-scale apparatus were carried out to investigate the roles of the ferromagnetic particles and the magnetic field applied in the desulfurization reaction. The results show that when ferromagnetic particles are used as the fluidization material, both sulfite (SO 3 2- ) salts and sulfate (SO 4 2- ) salts are found in the desulfurization products. When quartz particles are used, only sulfite (SO 3 2- ) salts are found. This suggests that the Fe(III) ions and Fe(II) ions result from the ferromagnetic particles dissolving in the liquid phase. In addition, the ions act as catalysts in the oxidation of S(IV) to S(VI) and react with SO 2 producing FeSO 3 and Fe 2 (SO 4 ) 3 as the products. On the other hand, the level of the sulfate (SO 4 2- ) salts in the products increases with increasing intensity of applied field intensity, which suggests that the oxidation of S(IV) can be enhanced by the applied magnetic field. The oxidation of S(IV) can increase the solubility of SO 2, and therefore, intensify the reaction between SO 2 and Ca(OH) 2 , leading to an increased SO 2 removal efficiency.

Fe2O3 particle catalysts were experimentally studied in the low temperature selective catalytic reduction (SCR) of NO with NH3. The effects of reaction temperature, oxygen concentration, [NH3]/[NO] molar ratio and residence time on SCR activity were studied. It was found that Fe2O3 catalysts had high activity for the SCR of NO with NH3 in a broad temperature range of 150-270 degrees C, and more than 95% NO conversion was obtained at 180 degrees C when the molar ratio [NH3]/[NO] = 1, the residence time was 0.48 seconds and O2 volume fraction was 3%. In addition, the effect of SO2 on SCR catalytic activity was also investigated at the temperature of 180 degrees C. The results showed that deactivation of the Fe2O3 particles occurred due to the presence of SO2 and the NO conversion decreased from 99.2% to 58% in 240 min, since SO2 gradually decreased the catalytic activity of the catalysts. In addition, X-ray diffraction, Thermogravimetric analysis and Fourier transform infrared spectroscopy were used to characterize the fresh and deactivated Fe2O3 catalysts. The results showed that the deactivation caused by SO2 was due to the formation of metal sulfates and ammonium sulfates on the catalyst surface during the de-NO reaction, which could cause pore plugging and result in suppression of the catalytic activity.

The influence of Fe in catalyst for low-temperature selective catalytic reduction of NO with NH 3 was investigated via altering the loading of Fe. A series of catalysts were prepared by impregnation method. The results show that the loading of Fe could improve the catalytic performance of the catalyst at low temperature. The removal efficiency of NOx could exceed 95% at the range of 150~230°C with 5Mn-5Zr-10Fe/Al 2 O 3 as catalyst. As the coexistence of Fe, Mn, Zr oxides enhance their dispersion on the carrier, there is not obvious oxide crystal on the catalyst. The specific surface area of catalyst can increase by loading of Fe. Consequently, the NH 3 adsorption properties might promote and low-temperature catalytic performance of catalyst can enhance.

Elementary studies of different catalysts on the fluidized bed are done based on iron and iron oxides in selective catalytic reduction (SCR). Under different temperatures and catalysts, there are distinct conversions. This paper compares the conversion of FeN Fe 2 O 3 and Fe 3 O 4 within a certain temperature range. The result indicated that the iron oxide has some activation of De-NOx , in particular the maghemite, the conversion of NO x on the pure maghemite reaches 91% at 250 degC.

The magnetically fluidized bed (MFB) was used as the reactor in a novel semidry flue gas desulfurization (FGD) process to achieve high desulfurization efficiency. Experiments in a laboratory-scale apparatus were conducted to reveal the effects of approach to adiabatic saturation temperature, Ca/S molar ratio and applied magnetic field intensity on SO 2 removal. Results showed that SO 2 removal efficiency can be obviously enhanced by decreasing approach to adiabatic saturation temperature, increasing Ca/S molar ratio, or increasing applied magnetic field intensity. At a magnetic field intensity of 300 Oe and a Ca/S molar ratio of 1.0, the desulfurization efficiency (excluding desulfurization efficiency in the fabric filter) was over 80%, while spent sorbent appeared in the form of dry powder. With the SEM, XRD and EDX research, it can be found that the increase of DC magnetic field intensity can make the surface morphology on the surface of the ferromagnetic particles loose and enhance the oxidation of S(IV), hence reducing the liquid phase mass transfer resistance of the slurry droplets and increasing desulfurization reaction rate, respectively. Therefore, the desulfurization efficiency increased obviously with the increase of DC field intensity.