Treatment titanium content

The catalysts used in the aforementioned studies were always titanium silicates of MFI structure prepared by hydrothermal synthesis. Ti can, however, be inserted in the silica lattice by post-synthesis treatment of a dealuminated H-ZSM-5 with TiCl4 vapor [11]. Titanium silicalite-2 (TS-2), with the MEL structure of ZSM-11, was prepared shortly after the first synthesis of TS-1 [15]. Both catalysts have been used for the hydroxylation of phenol. Kraushaar-Czarnetzki and van Hooff showed that no major catalytic differences resulted from the method of synthesis of TS-1 [11]. The slow rate of reaction they observed was probably the result of large crystal size and low titanium content [7]. Tuel and Ben Taarit demonstrated there was no perceptible difference between the catalytic activity of TS-2 and TS-1 [8]. This was predictable, because of the close similarity of the Ti-site structure, chemical composition, and pore dimensions of the two titanium silicates. 

The mild reduction with AlEtjCl has no effect on the distribution. Reimpregnation with TiCl only has a little effect on the titanium content, and also on NWD (RR catalyst). On the contrary, important changes are observed when the RAT or RRO treatments are used the Ti content increases to high values. The activity drops but the NWD corresponds to very broad distributions. The broadest distributions are observed with the RRO catalyst. 

By adjusting the content of cobalt, molybdenum, and titanium, the 18% nickel steel can attain yield strengths of 1380—2070 MPa (200,000—300,000 psi) after the aging treatment. Similarly, yield strengths of 12% nickel steel in the range of 1035—1380 MPa (150,000—200,000 psi) can be developed by adjusting its composition. 

The a — 0 transformation has a large hysteresis in hydrogenated titanium alloys, and different thermal treatments change their phase content. Various degrees of metastability due to hysteresis are implicit for the alloys after different thermal treatments. Metastable phases undergo transformation to a more equilibrium state during deformation, which can effect the flow of the alloy. Below we consider the effect of the thermal pre-strain treatment on ductility on the strength of the Ti-6A1-2Zr-1.5V-lMo-rH alloys. ... 

U.S. and one industrial waste water treatment in Spain. Engineering scale field experiments have been conducted by the National Renewable Energy Laboratory (NREL) at the Lawrence Livermore National Laboratory (LLNL) treating ground water contaminated with trichloroethylene (TCE) [253]. This field system consisted of 158 m2 of parabolic trough reactors and used De-gussa P25 particles (0.1%) as the photocatalyst in a slurry flow configuration. With this relatively low titanium dioxide content the TCE concentration was reduced from 200 ppb to less than 5 ppb. 

The results of XRD show that the anatase phase is formed at a temperature of 330°C for the pure titanium dioxide, while rutile phase is formed when the calcination temperature approached 630°C, indicating the beginning of the transformation from anatase to rutile. The anatase peaks in the XRD pattern disappears during the heat treatment of bare titanium dioxide at 700°C for Ih, suggesting the end of the transformation of anatase to rutile. The evolution of both anatase and rutile starts at higher temperature for silicon doped samples. However, the transition temperature of anatase to rutile progressively elevates when the silicon content is increased. Figure 1 shows the 29 diffraction scans for some of the samples annealed at 1000°C for Ih in air. It can be seen that the phase transition temperature... 

The insertion of Ti in the zeolite framework was accompanied by a significant decrease in A1 content (Table 1). However, there was no stoichiometric process between A1 removal and Ti insertion. Moreover, it was found that the treatment of Ig of an aluminum containing beta zeolite with a 75 ml of 3 x 10 M oxalic acid solution decreased the Si/Al ratio from its original value of 30 to 85 due to A1 extraction. Attempts to incorporate Ti into other zeolites like ZSM-12 and mordenite were not successful. Interestingly, the extraction of A1 from these zeolite structures was also unsuccessful with oxalic acid solutions with comparable concentrations. However, preliminary data show that siliceous mesoporous molecular sieves (MCM-41 and HMS) treated similarly with ammonium titanyl oxalate solutions exhibit good epoxidation activity. It is inferred that the presence of framework cations that can be extracted by oxalate species and/or the presence of defect sites in the parent zeolite is a requisite for the subsequent incorporation of titanium. 

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