Influence of Aluminum Sources on Synthesis of SAPO-34 and NH3-SCR of NOx by as-Prepared Cu/SAPO-34 Catalysts

Abstract

The full article will be published in the English version of the journal "Catalysis in Industry" No. 1, 2021.The synthesis of the microporous SAPO-34 molecular sieve goes from a combination of three templates: triethylamine, tetraethylammonium hydroxide, and morpholine under hydrothermal conditions. Two aluminum sources, namely aluminum hydroxide, and aluminum isopropoxide, were used exclusively to synthesize SAPO-34 zeolites. The effects of aluminum sources on the crystallization and physicochemical properties of SAPO-34 were studied thoroughly. The synthesized samples were characterized by using different characterization methods, including XRD, FE-SEM, N2 isotherm, EDS, and NH3-TPD. The results illustrate that the various sources of aluminum used for the synthesis of SAPO-34 materials extremely affect the crystallinity, morphology, and density of acid sites. Besides, the influence of aluminum sources on the performance of NH3-SCR technology was studied with Cu/SAPO-34 catalysts in a fixed-bed flow reactor. The two Cu/SAPO-34 catalysts promoted different NO and NH3 conversions between 200–600 °C though they share similar Cu content, which was loaded by the ion-exchange method in aqueous solution. In addition, the different Cu species in the two catalyst samples are surveyed by H2-TPR, while the EPR method is also used to assess the coordination of the copper element in the two catalysts.

Hybrid Cu-Fe/ZSM-5 Catalyst Prepared by Liquid Ion-Exchange for NOx Removal by NH3-SCR Process

“…However, depending on the metal loading, small amounts of aggregates composed of nanosized particles, particularly in the high amount of metal loading that can be created during calcination, emerge from the primary morphology of Fe/ZSM-5, Cu/ZSM-5, and Cu-Fe/ZSM-5. Or Doan et al note that the combined Cu x O or α-Fe 2 O 3 nanoparticles can be ascribed to particular layers of suspended matter [21]. Alongside the EDS results (Table 1) and the XRD patterns (Figure 2), this can be due to the fact that some large metal comprising agglomerations are welldistributed crystal metal oxide particles onto ZSM-5 composition.…”

“…e XRD patterns of all catalysts have included all characteristic peaks corresponding to ZSM-5, suggesting that ZSM-5 does not destroy its original form during the process of aqueous ion-exchange and calcination [20]. However, in contrast to those of the parent sample, the intensities of Fe/ZSM-5, Cu/ZSM-5, and Cu-Fe/ZSM-5 decrease due to the higher absorption coefficient of metal compounds for X-ray radiation or treatment with neutral aqueous solutions [21].…”