Comparative performance of copper and iron functionalized hydroxyapatite catalysts in NH3-SCR

Campisi, Sebastiano; Galloni, Melissa Greta; Bossola, Filippo; Gervasini, Antonella

doi:10.1016/j.catcom.2019.02.008

Cited by 37 publications

(23 citation statements)

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“…The intrinsic amphotericity of HAP support together with the redox activity of iron centres makes Fe/HAP samples promising candidates as NH 3 -SCR catalysts, as already presented in a recent paper. [13] HAP possesses both acid sites (attributed to Ca 2 + , surface HPO 4 2À and OH À vacancies) and basic sites (associated with PO 4 3À , OH À ) which can interact with NH 3 and NO, respectively, thus contributing to increase their surface concentration, which could give positive consequence on catalytic activity.…”

Section: Nh 3 -Scr Catalytic Resultsmentioning

confidence: 99%

“…A recent comparative study between copper‐ and iron‐modified HAP catalysts prepared by ion exchange procedure revealed that both catalyst series were active and selective for NH 3 ‐SCR reaction, even if in different operating temperature intervals. This evidence has important practical implications, allowing to select the proper catalyst according to the flue gas temperature window.…”

Section: Introductionmentioning

confidence: 99%

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Functionalized Iron Hydroxyapatite as Eco‐friendly Catalyst for NH₃‐SCR Reaction: Activity and Role of Iron Speciation on the Surface

et al. 2020

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Eco‐friendly catalysts have been obtained by functionalizing hydroxyapatite (HAP) with iron (Fe/HAP), according to three preparative methods (flash ionic exchange, deposition‐precipitation, and impregnation). Fe/HAP samples (ca. 2–7 wt.% Fe) have been tested in the reaction of NOx reduction by ammonia (NH3‐SCR) in the 120–500 °C interval with different NH3/NO ratios (0.6–2) at fixed contact time (0.12 s). All Fe/HAP samples were active and selective in the NH3‐SCR reaction starting from ca. 350 °C. Better performances have been observed on catalysts prepared by deposition‐precipitation and impregnation (about 70 % of NOx conversion and selectivity to N2 higher than 95 % at 350 °C), where α‐Fe2O3 and 3D‐Fe2O3 nanoclusters were present, as indicated by Mössbauer and UV‐Vis‐DR spectroscopies. On the opposite, paramagnetic Fe3+ centres were the predominant species on samples prepared by flash ionic exchange. Further characterization techniques (XRPD, N2‐physisorption, acidity by NH3 adsorption, and H2‐TPR) have concurred to elucidate Fe‐sitting HAP and structure‐activity relationships.

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Section: Nh 3 -Scr Catalytic Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Functionalized Iron Hydroxyapatite as Eco‐friendly Catalyst for NH₃‐SCR Reaction: Activity and Role of Iron Speciation on the Surface

et al. 2020

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“…The ion exchange capability of HAP derives from its peculiar structural flexibility which allows to replace framework Ca-ions (both Ca(I) and Ca(II) of the framework) with different ions (not only bivalent ions) without any distortion. In addition, HAP exhibits different acid and basic sites at its surface, which have been extensively exploited even in the field of heterogeneous catalysis, both as bare material (Fihri et al 2017) and metal-loaded support (Campisi et al 2019;Schiavoni et al 2018). In fact, the amphoteric nature of HAP surface has been recognized and quantification of acid/basic sites has been performed by titration in liquids (acid site titration with phenylethylamine in cyclohexane and water or basic site titration with benzoic acid, (Ferri et al 2018) and in gas phase (NH3-TPD and CO2-TPD, (Silvester et al 2014)).…”

Section: Graphical Abstract 1 Introductionmentioning

confidence: 99%

Nickel and cobalt adsorption on hydroxyapatite: a study for the de-metalation of electronic industrial wastewaters

2019

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In the present study, the Ni(II) and Co(II) adsorption efficiency and selectivity, as well adsorption mechanisms on a stoichiometric hydroxyapatite (HAP) surface have been investigated. Characterization studies (N2 adsorption/desorption and X-ray powder diffraction (XRPD) analyses) and adsorption tests under various operative conditions provided detailed information about the use of HAP in the de-metalation of wastewaters containing Ni and Co as polluted metal species. The sorption capacity of HAP has been evaluated by static batch adsorption tests varying initial concentration of Ni(II) and Co(II) species (from ca. 0.25 to 4.3 mM), contact time (from 15 min to 24 h), and pH (from 4 and 9) operative parameters. Proposed mechanisms of adsorption of Ni(II) and Co(II) on HAP surface are ion-exchange and surface complexation; a partial contribution of chemical precipitation from bulk solution should be considered at pH 9. In addition, adsorption isotherms of Ni(II) and Co(II) on HAP have been collected at 30°C and pH 4 and modeled by employing different equations. The maximum sorption capacities have been quantified as 0.317 mmol g-1 HAP (18.6 mg g-1 HAP) and 0.382 mmol g-1 HAP (22.5 mg g-1 HAP) for Ni(II) and Co(II), respectively. Selectivity to Co and Ni in the adsorption process on HAP has also been investigated; HAP has higher affinity towards Co than Ni species (Co:Ni=2.5:1, molar ratio).

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“…Ryu et al [164] studied the location of active sites in NH 3 -SCR reaction, mainly at Lewis acid sites on the catalyst surface. Campisi et al [165] functionalized HAP by ion exchange. The high dispersion of Fe 3+ species ensured the acid and redox centers.…”

Section: Nh 3 -Scrmentioning

confidence: 99%

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

Liu

et al. 2019

Catalysts

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Nitrogen oxides (NO x ) represent one of the main sources of haze and pollution of the atmosphere as well as the causes of photochemical smog and acid rain. Furthermore, it poses a serious threat to human health. With the increasing emission of NO x , it is urgent to control NO x . According to the different mechanisms of NO x removal methods, this paper elaborated on the adsorption method represented by activated carbon adsorption, analyzed the oxidation method represented by Fenton oxidation, discussed the reduction method represented by selective catalytic reduction, and summarized the plasma method represented by plasma-modified catalyst to remove NO x . At the same time, the current research status and existing problems of different NO x removal technologies were revealed and the future development prospects were forecasted.Catalysts 2019, 9, 771 2 of 39 adsorption, oxidation, reduction, and plasma methods. In view of these attentive findings, adsorption method uses recyclable solid adsorbent material to adsorb NO x from flue gas through microporous structure, remarkably, environmentally friendly, no secondary pollution, and energy-saving and -efficient features make it stand out [18][19][20]. The oxidation process is a method that oxidizes NO into NO 2 or N 2 O 3 with high solubility under the action of an oxidant that is then absorbed by water or alkali solution. The process is simple and cost-saving, and is widely used in the wet flue gas denitrification process with relatively low cost and high removal efficiency of NO x ; except that the oxidized NO and SO 2 can be removed simultaneously to produce high value-added products [21][22][23]. The reduction method has the characteristics of high efficiency, cleanliness, and mildness; NO x removal can be realized at low temperature at present [24][25][26]. The plasma method is used to modify the surface of the catalyst, the dispersion of active species can be improved by plasma treatment, and the stability and low temperature activity of catalyst can be improved [27,28].Seldom, if ever, does a comprehensive article to introduce the current situation and treatment methods of removing NO x . In this paper, we tried to renovate, classify, and summarize the significant perspectives and most relevant findings reported in recent research articles and earlier reviews generalizing the mechanism analysis and research progress of NO x removal by adsorption, oxidation, reduction, and plasma methods, which can provide means for promoting the technological progress of pollution prevention, maintaining healthy development of factories continuously, studying the methods of removing NO x deeply, and mastering different technologies of removing NO x , as well as providing guidance for controlling the emission of NO x from motor vehicles such as diesel, gasoline, and so on. In order to improve the environmental quality and save the ecological environment, this paper further provides a convenient, low-cost, efficient, and economic guidance line.

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Comparative performance of copper and iron functionalized hydroxyapatite catalysts in NH3-SCR

Cited by 37 publications

References 31 publications

Functionalized Iron Hydroxyapatite as Eco‐friendly Catalyst for NH₃‐SCR Reaction: Activity and Role of Iron Speciation on the Surface

Functionalized Iron Hydroxyapatite as Eco‐friendly Catalyst for NH₃‐SCR Reaction: Activity and Role of Iron Speciation on the Surface

Nickel and cobalt adsorption on hydroxyapatite: a study for the de-metalation of electronic industrial wastewaters

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

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Comparative performance of copper and iron functionalized hydroxyapatite catalysts in NH3-SCR

Cited by 37 publications

References 31 publications

Functionalized Iron Hydroxyapatite as Eco‐friendly Catalyst for NH3‐SCR Reaction: Activity and Role of Iron Speciation on the Surface

Functionalized Iron Hydroxyapatite as Eco‐friendly Catalyst for NH3‐SCR Reaction: Activity and Role of Iron Speciation on the Surface

Nickel and cobalt adsorption on hydroxyapatite: a study for the de-metalation of electronic industrial wastewaters

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

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Product

Resources

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Functionalized Iron Hydroxyapatite as Eco‐friendly Catalyst for NH₃‐SCR Reaction: Activity and Role of Iron Speciation on the Surface

Functionalized Iron Hydroxyapatite as Eco‐friendly Catalyst for NH₃‐SCR Reaction: Activity and Role of Iron Speciation on the Surface