Papers by Keyword: Y-Zeolite

Abstract: Desulfurization of thiophene from model gasoline was carried out by using large charge number metal (Bi, Sb, Zr and Ru) ion modified NH₄Y-zeolite by batch method. The sulfur uptake increased in the order of HY (0.85 mg/g) < BiY-1 (1.06 mg/g) < SbY-1(1.24 mg/g) < ZrY-1 (1.25 mg/g) < RuY-1 (1.35 mg/g). Sulfur uptake was influenced by Ru contentof RuY, which increased in the order of RuY-0.25 (1.11mg/g) < RuY-1 (1.41mg/g) < RuY-0.5 (1.68 mg/g). Sulfur removal was influenced by aromatics of model gasoline, i.e., sulfur removal of RuY-0.5 (42%) showed higher selectivity for thiophene than CeY-1 (24%) ones when model gasoline with toluene.

Abstract: Synthesis of bulky Y-zeolite was attempted by a hydrothermal hot-pressing (HHP) method. These bulky products synthesized under hydrothermal conditions were identified as Y-zeolite single phase. Especially, bulky Y-zeolite having translucency, high density and large surface area was obtained by HHP treatment at 423K for 2h with 17wt% of 5M-NaOH solution. This solidified zeolite like single-crystal was considered to be made by dissolution and precipitation mechanism. High-density bulky zeolites can be expected as novel molecular sieves and catalysts with high activity.

Abstract: A series of cation exchanged Y-zeolites were prepared by exchanging cations with various alkali (M+, M= Li, Na, K, Cs) metals. The structural and catalytic properties of the alkali metal exchanged Y-zeolites have been investigated by a number of analytical techniques. Comparative elemental analyses were determined by an Energy Dispersive Spectroscopy X-ray (EDS), X-ray Photoelectron Spectroscopy (XPS), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) and X-ray Fluorescence (XRF) before and after cation substitution. The framework and non-framework Al coordination and the Si/Al ratios of the Y-zeolites were investigated by MAS Solid-State Nuclear Magnetic Resonance (NMR) spectroscopy. The Al NMR spectra were characterized by two 27Al resonance signals at 12 and 59 ppm, indicating the presence of the non-framework and framework Al respectively. The intensities of these resonances were used to monitor the amount of the framework and non-framework Al species in the series of exchanged zeolites. The 29Si NMR spectra were characterized by four resonance signals at -79, -84, -90, and -95 ppm. Changing the alkali metal cations in the exchanged Y-zeolites significantly altered the extent of the octahedral/tetrahedral coordination and the Si/Al ratio. The Fourier Transform Infrared spectra of the CO2 adsorbed on to the exchanged Y-zeolites showed a low frequency shift, as the atomic number of the exchanged alkali metal increased. In addition, the catalytic activity of these samples for NOx reduction were tested in combination with a non-thermal plasma technique and interpreted based on the above structural and spectroscopic information.