Catalytic iron wall

Figure 21.4. The cross-sectional view of the setup used in the pilot test for in situ remediation of a chlorinated-hydrocarbons-contaminated site by the combined technologies of EK processing-Fenton process-catalytic iron wall.

TABLE 2L1. Concentration Variations of Major Contaminants Detected in the Monitoring Well in an In Situ Pilot Test Using EK-Fenton-Catalytic Iron Wall Technology... 

Hung YC. (2002). Pilot-Scale in Situ Treatment of a Chlorinated Hydrocarbons Contaminated Site by Combined Technologies of Electrokinetic Processing-Fenton Process-Catalytic Iron Wall. MS Thesis, National Sun Yat-Sen University, Kaohsiung, Taiwan. 

An exhaustive study has been carried out recently on the synthesis of BN nanotubes and nanowires by various CVD techniques.17 The methods examined include heating boric acid with activated carbon, multi-walled carbon nanotubes, catalytic iron particles or a mixture of activated carbon and iron particles, in the presence of ammonia. With activated carbon, BN nanowires are obtained as the primary product. However, with multi-walled carbon tubes, high yields of pure BN nanotubes are obtained as the major product. BN nanotubes with different structures were obtained on heating boric acid and iron particles in the presence of NH3. Aligned BN nanotubes are obtained when aligned multi-walled nanotubes are used as the templates (Fig. 40). Prior to this report, alignment of BN nanotubes was achieved by the synthesis of the BN nanotubule composites in the pores of the anodic alumina oxide, by the decomposition of 2,4,6-trichloroborazine at 750 °C.116 Attempts had been made earlier to align BN nanotubes by... 

Exhaustive studies have been carried out on the synthesis of BN nanotubes and nanowires by various CVD techniques [225]. The methods examined include heating boric acid with activated carbon, multi-walled carbon nanotubes, catalytic iron particles or a mixture of activated carbon and iron particles, in the presence of ammonia. With activated carbon, BN nanowires are obtained as the primary prod-... 

The reaction is completed when the blue color of dissolved sodium spreads through the solution. The color must be detected where the liquid splashes against the walls, because the body of the solution is quite- dark from the catalytic iron. 

Scientists from Politecnico di Milano and Ineos Vinyls UK developed a tubular fixed-bed reactor comprising a metallic monolith [30]. The walls were coated with catalytically active material and the monolith pieces were loaded lengthwise. Corning, the world leader in ceramic structured supports, developed metallic supports with straight channels, zig-zag channels, and wall-flow channels. They were produced by extrusion of metal powders, for example, copper, fin, zinc, aluminum, iron, silver, nickel, and mixtures and alloys [31]. An alternative method is extrusion of softened bulk metal feed, for example, aluminum, copper, and their alloys. The metal surface can be covered with carbon, carbides, and alumina, using a CVD technique [32]. For metal monoliths, it is to be expected that the main resistance lies at the interface between reactor wall and monolith. Corning... 

Figure 5.7 Three-dimensional drawing of the experimental system used to assess the catalytic properties of the amorphous iron silicate smokes. The (smoke) catalyst is contained in the bottom of a quartz finger (attached to a 2L Pyrex bulb) that can be heated to a controlled temperature. A Pyrex tube brings reactive gas to the bottom of the finger. The gas then passes through the catalyst into the upper reservoir of the bulb and flows through a copper tube at room temperature to a glass-walled observation cell (with ZnSe windows) in an P iiR spectrometer. From there, a closed-cycle metal bellows pump returns the sample via a second 2L bulb and the Pyrex tube to the bottom of the catalyst finger to start the cycle over again (Hill and Nuth 2003).

The initial wall activity diminished as less active carbon builds upon the walls decreasing available active sites. The initial activity of nickel was clearly lower than that of low carbon steel, but higher than that of stainless steel. The results are in general agreement with the conclusions of Tamai, et al. (1968) and Buell and Weber (1950). The former indicated that nickel had a lower "affinity to olefins than iron, while the latter concluded that the nickel content in austenitic steel alloys is primarily responsible for their activity (carbon formation) when compared to the less active chrome steel alloys. The carbon-conditioned nickel walls were less active than those of low carbon steel reactor probably because the catalytic activity of the base metal did not penetrate through the carbon layer as effectively as it did with low carbon steel. 

Single-walled nanotubes purified from Meijo University at Nagoya (SWNTs). These nanotubes were synthesized by electric arc discharge (iron was used as catalytic particles) and then purified by annealing at 693 K and a mild hydrochloric acid treatment [1(X)]. Double-walled nanotubes (DWNTs) synthesized by CVD at CIRIMAT at Toulouse University. These nanotubes were synthesized by the CVD process. Catalytic nanoparticles are formed from solid solutions of Mgi cCO cMOj,0. The synthesis method used is the same as that described by Bacsa et al. [101] but with small differences in the catalytic nanoparticles synthesis. 

The comparison of the tribological performances of these two samples proves the necessity to eliminate iron catalytic particles of nanotubes samples. Indeed, contrary to nickel catalytic particles, which have a benefit effect on the tribological properties of single-walled nanotubes, iron catalytic particles seem to be less effective. To complete this study, it would be interesting to test multiwalled nanotubes containing Ni nanoparticles. 

Besides the use of vanadium-based catalysts, a wide variety of other catalyst compositions were reported. A recent review focussed on FeSbO based catalysts promoted by appropriate additives as suitable for the ammoxidation of alkyl-substituted aromatics and hetero aromatic compounds. A unique preparation method of a fluid-bed catalyst is presented using nitric acid oxidation of antimony trioxide catalyzed with iron ions. The catalysts thus prepared have superior catalytic and physical properties. [78]. In addition, some unique compositions were reported by different research groups. For instance, new ammoxidation catalysts based on rhenium carbonyl cluster complexes containing antimony and bismuth ligands were reported by Adam et al. [79]. Single-site multifunctional catalysts based on [Cu RUj C ] nanocluster anchored to inner walls of mesoporous silica were also used in the ammoxidation of 3P [80]. 

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