To enable zeolite to trap bulky environment pollutants such as tobacco specific nitrosamines (TSNAs), we tailored the porous structure of MCM-22 zeolite by desilication to obtain a sample with mesopores centered 3.5 nm, in order to promote the mass transport. The meso-MCM-22 was further functionalized with -SO(3)H group to enhance the efficiency in adsorption of TSNAs. The composites were characterized by XRD and BET methods, and their adsorptive function was assessed in both liquid adsorption of N'-nitrosonornicotine (NNN) and the adsorption of TSNAs in aqueous tobacco-extract solution. Grafting -SO(3)H group on alkaline-treated MCM-22 significantly elevated the adsorption toward nitrosamines, and the resulting composite could reduce above 70% of NNN in dichloromethane solution or 54% of TSNAs in tobacco-extract solution.
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http://dx.doi.org/10.1016/j.jhazmat.2010.03.108 | DOI Listing |
Langmuir
December 2024
Key Laboratory for Green Chemical Process of Ministry of Education, Hubei Novel Reactor & Green Chemical Technology Key Laboratory, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, Hubei 430205, China.
The synergetic effect of different zinc active sites with a Brønsted acid site (BAS) in Zn-MCM-22 for -octane dehydrogenation cracking and ethane dehydroaromatization was investigated. Zn-MCM-22 catalysts containing ZnO were prepared via incipient wetness impregnation (IM) using liquid ion grafting, whereas those containing [ZnO] were prepared via atom-planting (AP) using the gas dechlorination reaction. The synergetic effects of BAS with micropore incorporated [ZnO] and external surface ZnO species on the dehydrogenation of different molecule size reactants -octane and ethane were compared.
View Article and Find Full Text PDFJ Am Chem Soc
October 2024
Center for Ordered Nanoporous Materials Synthesis, Division of Environmental Science and Engineering, POSTECH, Pohang 37673, Korea.
Despite extensive efforts over the past several decades, the current mechanistic understanding of zeolite crystallization is still far from satisfactory, thus precluding the synthesis of designer zeolites. Here we show that the nucleation and in situ transformation pathways during the synthesis of medium-pore zeolite TNU-9 can be altered by controlling the extent of cooperative structure direction between Na and Cs ions in the presence of 1,4-bis(-methylpyrrolidinium)butane cations as an organic structure-directing agent. The intermediate phase selectivity was found to change from bikitaite to analcime to layered MCM-22 precursor when the gel Na/Cs ratio was adjusted to 7, 15, and 20, respectively.
View Article and Find Full Text PDFMolecules
August 2024
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, China.
γ-valerolactone (GVL), derived from biomass, is a crucial platform compound for biofuel synthesis and various industrial applications. Current methods for synthesizing GVL involve expensive catalysts and high-pressure hydrogen, prompting the search for greener alternatives. This study focuses on a novel zirconium phosphate (ZrP)-pillared zeolite MCM-36 derivative catalyst for converting levulinic acid (LA) to GVL using alcohol as a hydrogen source.
View Article and Find Full Text PDFMacromol Rapid Commun
October 2024
National Energy R&D Center for Biorefinery, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
A high-quality filler within mixed matrix membranes, coupled with uniform dispersity, endows a high-efficiency transfer pathway for the significant improvement on separation performance. In this work, a zeolite-typed MCM-22 filler is reported that is doped into polydimethylsiloxane (PDMS) matrix by ultrafast photo-curing technique. The unique structure of nanosheets assembly layer by layer endows the continuous transfer channels towards penetrate molecules because of the inter-connective nanosheets within PDMS matrix.
View Article and Find Full Text PDFMolecules
March 2024
School of Chemical Engineering, Northwest University, Xi'an 710069, China.
To improve the mess-specific activity of Co supported on zeolite catalysts in Fischer-Tropsch (FT) synthesis, the Co-MCM-22 catalyst was prepared by simply grinding the MCM-22 with nanosized CoO prefabricated by the thermal decomposition of the Co(II)-glycine complex. It is found that this novel strategy is effective for improving the mess-specific activity of Co catalysts in FT synthesis compared to the impregnation method. Moreover, the ion exchange and calcination sequence of MCM-22 has a significant influence on the dispersion, particle size distribution, and reduction degree of Co.
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