Study on Effect and Mechanism of Alkaline Earth Metal Poisoning on Cu/SSZ-13 Catalysts for Selective Catalytic Reduction of NO_x with NH₃

Abstract

In order to study the poisoning effect of the alkaline earth metal on Cu/SSZ-13 and reveal the poisoning mechanism, Cu/SSZ-13 zeolite catalysts were synthesized by the ion-exchange method and poisoned by different concentrations of Mg and Ca. The results of SCR tests and characterizations showed that the SCR activity of Cu/SSZ-13 catalysts decreased obviously after Mg or Ca poisoning, which is because Mg and Ca reduced the Cu 2+ species and Brønsted acid sites in Cu/SSZ-13, while increasing the content of Cu x O y . Furthermore, Mg and Ca on the catalyst surface could block the pores of the zeolite and then decrease the specific surface area of the catalysts, and Ca could further cause partial collapse of the zeolite skeleton. Through this article, the effect and mechanism of alkali earth metal poisoning of Cu/SSZ-13 were revealed, which provided data and theory support for the development of efficient Cu/SSZ-13 NH 3 -SCR catalysts with high alkali earth metal resistance.

Leaching Vanadium from the Spent Denitration Catalyst in the Sulfuric Acid/Oxalic Acid Combined Solvent

“…The SEM images present irregular-shaped and rod-shaped morphologies of the raw spent denitration catalyst. The EDS spectra analyses of regions (a) and (b) indicated that the major irregular particles contained W and Ti, whereas rod-shaped particles as binders mainly contained other elements, such as Al, Si, and V. Moreover, the V was encapsulated in the mineral phase with the V-bearing lattice structure (Al–Si–O–V compound) attributed to the prolonged high-temperature sintering during the denitration catalytic process. − Obviously, only if the V-bearing lattice structure was destroyed by the leaching solvent could ensure a high leaching rate of V …”

Effect of Various Acid Anions on Potassium Poisoning and the Mechanism of Commercial V2O5–WO3/TiO2 Catalysts for SCR of NOx

“…Nitrogen oxides (denoted NO x ) emitted from stationary and mobile sources are one of the major air pollutants, which lead to diverse environmental problems such as photochemical smog, haze, and acid rain. , Due to its low cost, simple equipment, and high catalytic denitration efficiency, selective catalytic reduction of NO x with NH 3 (denoted NH 3 -SCR) has become a mainstream process for reducing NO x emission in the flue gas. , V 2 O 5 –WO 3 /TiO 2 (denoted VWTi), which consists of 1–2 wt % V 2 O 5 as an active component and 3–8 wt % WO 3 as a promoter supported on TiO 2 , is the most extensively used catalyst system in the SCR process . This is primarily attributed to its stable high denitrification efficiency and suitable operating temperature range for coal-fired plants.…”