Senderov E.,Rive Technology |
Halasz I.,PQ Corporation |
Olson D.H.,Rutgers University
Microporous and Mesoporous Materials
The removal of Al with acid solution from a zeolite framework is customarily associated with formation of framework defects known as hydroxyl nests, but their existence has not been unambiguously confirmed thus far. TPD and FTIR techniques were used here to identify such hydroxyl nests in a 22% acid dealuminated zeolite Y by comparing it to its non-dealuminated parent counterpart. Both zeolites, parent and dealuminated, were analyzed in fully alkaline Cs, Na ion exchanged form. TPD analysis showed that hydroxyl nests cannot be present in samples calcined above 200 C. FTIR study did not find any evidence for the existence of such units even in hydrated samples which had never been subjected to modification at temperatures higher than 80 C. © 2013 Elsevier Inc. All rights reserved. Source
Pq Corporation | Date: 2014-05-23
This invention relates to a composition and method of fracturing subterranean formations utilizing a polymerized alkali silicate. The fracturing fluid includes an alkali silicate such as sodium silicate and an acid such as hydrochloric acid. The sodium silicate is polymerized to a silica gel using an acid. The resulting silica gel has a pH from about 2 to less than 7.5.
Pq Corporation | Date: 2012-04-17
There is disclosed a method to synthesize microporous crystalline material comprising a metal containing chabazite having a crystal size greater than 0.5 microns and a silica-to-alumina ratio (SAR) between 5 and 15, wherein the method is carried out without the use of an organic structural directing agent and without requiring calcination. There is also disclosed a large crystal organic free chabazite made according to the disclosed method. In addition, there are disclosed methods of using the disclosed crystalline material, such as in the selective catalytic reduction of NO
Pq Corporation | Date: 2012-11-30
There is disclosed a microporous crystalline material having pore opening ranging from 3 to 5 Angstroms, where the material comprises a first metal chosen from alkali earth group, rare earth group, alkali group, or mixtures thereof, and a second metal chosen from iron, copper or mixtures thereof; and has a molar silica to alumina ratio (SAR) from 3 to 10. The microporous crystalline material disclosed herein may comprise a crystal structure having building units of double-6-rings (d6r) and pore opening of 8-rings as exemplified with framework types defined by the Structure Commission of the International Zeolite Association having structural codes of CHA, LEV, AEI, AFT, AFX, EAB, ERI, KFI, SAT, TSC, and SAV. There is also disclosed a method of selective catalytic reduction of nitrogen oxides in exhaust gas, comprising at least partially contacting the exhaust gases with an article comprising the disclosed microporous crystalline material.
Pq Corporation | Date: 2011-06-23
A process for preparation of silica xerogel catalyst support particles having high surface areas involves ageing a silica hydrogel at a pH from 3 to 5 and at a temperature of 45 C. or more. The ageing at low pH leads to a silica gel which may be converted to a xerogel having a pore volume of 1.5 cm