An FT-IR study of the adsorption of urea and ammonia over V2O5–MoO3–TiO2 SCR catalysts

Larrubia, M.Á.; Ramis, Gianguido; Busca, Guido

doi:10.1016/s0926-3373(00)00150-8

Cited by 232 publications

(134 citation statements)

References 9 publications

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“…Washing the gliadin films in water was effective in removing most of the urea from the films based on the FTIR spectrum in Figure 1. The typical absorption peaks of urea at about 1682 cm −1 (C=O stretching) and at 3320 and 3420 cm −1 (N-H stretching) are seen in the urea spectrum but are absent in the gli-adin films [15]. In addition, a spectrum of pure gliadin powder was subtracted from the gliadin film spectrum and the spectrum after subtraction did not show any match with urea confirming that the films did not contain detectable urea.…”

Section: Confirming Removal Of Ureamentioning

confidence: 92%

Developing Water Stable Gliadin Films Without Using Crosslinking Agents

Reddy

Yang

2010

J Polym Environ

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For the first time, gliadin films with excellent strength and water stability have been developed without using any crosslinking agents. So far, it has not been possible to obtain water stable gliadin films even after crosslinking. In this research, a novel method of using aqueous urea and ethanol has been developed to obtain highly water stable gliadin films without using crosslinking chemicals. The effects of concentrations of gliadin, urea and ethanol on the strength of the films and the stability of the films in water at high temperatures and various pH conditions has been studied. Gliadin films developed in this research have strength of about 30 MPa similar to the strength of previously reported gliadin films crosslinked with aldehydes and cysteine. Gliadin films obtained in this research were stable in pH 7.2 water at 50 °C for 20 days. The gliadin films did not dissolve in 70% ethanol which readily dissolves gliadin powder.

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Section: Confirming Removal Of Ureamentioning

confidence: 92%

Developing Water Stable Gliadin Films Without Using Crosslinking Agents

Reddy

Yang

2010

J Polym Environ

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“…The reaction cannot occur when NH 3 and NO are in the gas phase. 42 If the reaction of NO with NH 3 occurs, the latter, which should be in the adsorption state, would react with NO. Figure 4a illustrates that the NH 3 desorption rate is lower than its adsorption rate, indicating that NH 3 can be adsorbed onto the Lewis acid or Brønsted acid sites present on the catalytic surface.…”

Section: Adsorption Performance Of the Catalystmentioning

confidence: 99%

De-NOx Performance and Mechanism of Mn-Based Low-Temperature SCR Catalysts Supported on Foamed Metal Nickel

Zhu

Song

et al. 2018

J. Braz. Chem. Soc.

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A series of manganese-based catalysts supported on foamed metal nickel (FMN) with various Mn/Ni ratios was prepared for low-temperature selective catalytic reduction (SCR) of NO with NH 3 (NH 3 -SCR). The effects of calcination temperature, amount of added Mn, optimal operating conditions, and H 2 O on the elimination of nitrogen oxides (de-NO x ) performance of catalysts were studied. The catalysts were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and temperature-programmed desorption experiments of NH 3 analyses. The experimental results revealed that the Mn 7.5 /FMN catalyst calcined at 350 °C exhibited the best NO conversion that was ca. 100% at 120-200 °C. Moreover, it had excellent H 2 O tolerance. The superior activity of the Mn 7.5 /FMN catalyst, which was calcined at 350 °C, was attributed to the presence of amorphous manganese oxide, more unsaturated Ni atoms and structural defects, an increase in NH 3 adsorbance, and the number of surface acid sites. Based on these studies, we established that the reaction of the NH 3 -SCR with Mn 7.5 /FMN catalyst mainly exhibits an Eley-Rideal mechanism.Keywords: de-NO x , low-temperature SCR, MnO x , foamed metal nickel, mechanism IntroductionNitrogen oxides (NO x ) such as NO and NO 2 resulting from fossil fuel combustion are one of the main pollutants in the atmosphere. NO x gases are responsible for acid rain, photochemical smog, and ozone layer depletion. At high levels, they affect the respiratory system, and long-term exposure can damage lung function.1-3 Currently, several methods are used to eliminate NO x (de-NO x ). Selective catalytic reduction (SCR) of NO with NH 3 (NH 3 -SCR) is one of the most effective ways to reduce NO x emissions. [4][5][6][7][8] The reactions are as follows: As a core link in this technology, the catalyst performance directly affects the de-NO x efficiency of the whole SCR system. 9,10 The V 2 O 5 -WO 3 (MoO 3 )/TiO 2 catalyst is a commonly used commercial SCR catalyst for NO x removal with an active temperature range of 300-400 °C. 11,12 However, this catalyst has many disadvantages including the toxicity of vanadium at high temperatures.13 Therefore, significant efforts should be devoted towards the development of non-vanadium catalysts for NH 3 -SCR processes. Mn-based catalysts have been studied due to their inherent environmentfriendly characteristics and excellent SCR activity at low temperatures. [14][15][16][17][18][19] Zhu et al. 1681 Vol. 29, No. 8, 2018 co-workers 22 studied the low-temperature de-NO x activity of Mn-Ce/TiO 2 and Mn-Ce/Al 2 O 3 catalysts. The results indicated that the de-NO x performance of the Mn-Ce/TiO 2 catalyst was better than that of the Mn-Ce/Al 2 O 3 catalyst at temperatures of 80-150 °C. Although the Mn-based catalysts exhibit high low-temperature activities, there are significant differences in their low-temperature SCR activity. [23][24][25] Moreover, the role of the carrier should not be ignored. 26,27 Foamed metal nickel (FMN) with...

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“…11 HNCO(gas)+H 2 O(gas) − −− → NH 3 (gas)+CO 2 (gas) (4) Through reactions (2)-(4), NH 3 is generated from urea and is believed to be the active reducing agent. 11,14,16 In this study, the characteristics of SCR of NO by urea in a fluidized-bed reactor have been determined using the fresh and sulfated CuO/γ -Al 2 O 3 catalysts with simulated flue gas. Recently, Sirdeshpande and Lighty 17 reported that CuO/γ -Al 2 O 3 activity is reduced by the water content of the flue gas.…”

Section: 15mentioning

confidence: 99%

Selective catalytic reduction by urea in a fluidized‐bed reactor

Roh

Jung

Jeong

et al. 2003

J of Chemical Tech & Biotech

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The selective catalytic reduction (SCR) of NO x by urea as a reducing agent was carried out over fresh and sulfated CuO/γ -Al 2 O 3 catalysts in a fluidized-bed reactor. The optimum temperature ranges for NO reduction on the fresh and sulfated CuO/γ -Al 2 O 3 catalysts were 300-350• C and 400-450 • C, respectively. NO reduction with the sulfated CuO/γ -Al 2 O 3 catalyst was somewhat higher than that with the fresh CuO/γ -Al 2 O 3 catalyst. N 2 O formation increased with increasing reaction temperature. Ammonia (NH 3 ) slip increased with increasing gas velocity and decreased with increasing reaction temperature.

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An FT-IR study of the adsorption of urea and ammonia over V2O5–MoO3–TiO2 SCR catalysts

Cited by 232 publications

References 9 publications

Developing Water Stable Gliadin Films Without Using Crosslinking Agents

Developing Water Stable Gliadin Films Without Using Crosslinking Agents

De-NOx Performance and Mechanism of Mn-Based Low-Temperature SCR Catalysts Supported on Foamed Metal Nickel

Selective catalytic reduction by urea in a fluidized‐bed reactor

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