Hydrothermal temperature

T. Sugama, L. E. Kukacka, N. Carciello, and B. Galen. Oxidation of carbon fiber surfaces for improvement in fiber-cement interfacial bond at a hydrothermal temperature of 300° C. Cement Concrete Res, 18(2) 290-300, March 1988. 

Table 1. Effect of hydrothermal temperature on the methylene blue(MB) adsorbed, interlayer silicate content and 001 spacing of silicate-bearing hectorites...

The gel solution mixtures were packed in ampoules and crystallized at 100°C for various periods from 0.25 to 131 days. The solid products were washed with water to pH = 9 and dried overnight at 100°C, then calcined under passage of air at 540°C for 3 5 h. The molar ratio of Si/Al, (Na + K)/A1, K/(Na + K), and choline/0H were fixed at 9-3, 7.3 0.17, and 0.67, respectively. Based on the analysis of the slow crystallization rate process, the hydrothermal treatment was properly shortened by a temperature-programmed crystallization. Furthermore, the effects of seed materials, type of template, hydrothermal temperature, and Si/Al ratio of the gel mixture on the crystallization were investigated. 

No. Hydrothermal Temperature (K) Pa (nm) Pd (nm) Unit Cell Parameter (nm) Pore Volume (cmVg) BET Surface Area (mVg)... 

The SEM images of the as-synthesized SBA-16L (413 K) shows a crystal-like morphology with a uniform size of 5 pm. The crystals consist of 20 clear crystal faces with 2 hexagons, 12 trapeziums and 6 rectangles. Similar to that reported by Che et al., the crystal faces of the particles increase with the hydrothermal temperature [10]. 

No. Hydrothermal temperature (K) Cavity size (nm) Window size (nm) Cell parameter (nm) Pore volume (cmVg) Surface area (mVg)... 

Powders are anhydrous, crystalUne, or amorphous depending on the hydrothermal temperature. 

Ci 3(EO)6 surfactant at 100 °C still presented the y-MnOa phase, but a pure phase of y-MnOOH with high crystallinity could be obtained after hydrothermal treatment at 120 °C in the Ci3(EO)6 solution. It has been known that hydrothermal treatment in water at high temperature of 200 °C could result in the formation of pure y-MnOOH phase (Fig. 1). This indicates that the presence of PEO-surfactant could efficiently reduce the hydrothermal temperature of the pure y-MnOOH formation. SEM images of the y-MnOOH synthesized in the Ci3(EO)6 solution at 120 °C show a lot of rods mixed with small granular particles and a small quantity of nanowires (Fig. 5). 

J. Yu, G. Wang, B. Cheng, M. Zhou, Effects of hydrothermal temperature and time on the photocatalytic activity and microstructures of bimodal mesoporous Ti02 powders . Applied Catalysis B Environmental, 69,171-180, (2007). 

Figure 17c shows the normalized LCM PL spectra for single pristine and HT P3HT NPs averaged over 20 different dry NPs. The intensity and position of the 0-1 emission peak at 692—708 nm were different for the individual NPs and varied with the hydrothermal temperature. Its dominance increased for the HT060 and HTllO... 

Obtained at 120 °C hydrothermal temperature (B) DRS spectra of pure AgCl and Ag/AgCl composite (C) Schematic model of the photo-... 

Cu-SSZ-13. Clearly the zeolite retains its crystal structme longer, at more severe hydrothermal temperatures [17],... 

Yao et al. [47] have synthesized zeolite Li-ABW from fly ash by alkaline fusion followed by hydrothermal treatment in LiOH H2O medium. It has been reported the crystallinity of zeolites is as high as 97.8 % corresponding to 3 M LiOH H2O concentration, hydrothermal temperature range 80-180 °C and aging time, 2-16 h. It has been found that the soluble species in the supernatant produce different zeolitic crystals by transformation after re-crystallization. They have confirmed the presence of rod shaped stable crystals which consist of meso-pores by employing characterization tools such as XRD, FT-IR, SEM, TGA-DTA and N2 adsorption isotherms. 

In this context, the role of NaOH has been established by several researchers [2, 5-7]. Accordingly, the stock solution of NaOH, based on its high corrosive property, has been assumed to cause significant etching of the fly ash ingredients at the hydrothermal temperature of 100 °C. The experiment was carried out in a fabricated set up, which comprises of a 10 L reactor fitted with an open reflux condenser, thermostatically controlled heater and a magnetic stirrer. A schematic sketch of the experimental set up is presented in Fig. 5.1. 

From the enthalpy data available in the literature. Wood (1992) determined stability constants for Be20H " and Be3(OH)3 " at hydrothermal temperatures (to... 

Figure 14. Influence of the concentration of Ba(OH)2 and the hydrothermal temperature on the morphology and structure of BaTi03 products prepared from (a) Na2Ti307 nanotubes and (b) Na2Ti307 nanowires[135]. 

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