title: Improving Stability of Zeolites in Aqueous Phase via Selective Removal of Structural Defects.
abstract: Missing silicon-oxygen bonds in zeolites are shown to be the cause for structural instability of zeolites in hot liquid water. Their selective removal drastically improved their structural stability as demonstrated using zeolite beta as example. The defects in the siloxy bonds were capped by reaction with trimethylchlorosilane, and Si-O-Si bonds were eventually formed. Hydrolysis of Si-O-Si bonds of the parent materials and dissolution of silica-oxygen tetrahedra in water causing a decrease in sorption capacity by reprecipitation of dissolved silica and pore blocking was largely mitigated by the treatment. The stability of the modified molecular sieves was monitored by (29)Si-MAS NMR, transmission electron micrographs, X-ray diffraction, and adsorption isotherms. The microporosity, sorption capacity, and long-range order of the stabilized material were fully retained even after prolonged exposure to hot liquid water.
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory , P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Prodinger
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory , P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Miroslaw A
authors.initials: MA
authors.lastname: Derewinski
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory , P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Aleksei
authors.initials: A
authors.lastname: Vjunov
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory , P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Sarah D
authors.initials: SD
authors.lastname: Burton
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory , P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Ilke
authors.initials: I
authors.lastname: Arslan
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory , P.O. Box 999, Richland, Washington 99352, United States.|Department of Chemistry and Catalysis Research Institute, TU München , Lichtenbergstrasse 4, 85748 Garching, Germany.
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Lercher