Nano-iron

Interestingly, free nano-iron oxide particles are active catalysts for the selective oxidation of alcohols to yield the corresponding aldehydes/ketones [72, 73]. Different aromatic alcohols and secondary aliphatic alcohols were oxidized with high selectivity, but at low conversion. Here, further improvement should be possible (Scheme 25). 

Under microwave irradiation and applying MCM-41-immobilized nano-iron oxide higher activity is observed [148]. In this case also, primary aliphatic alcohols could be oxidized. The TON for the selective oxidation of 1-octanol to 1-octanal reached to 46 with 99% selectivity. Hou and coworkers reported in 2006 an iron coordination polymer [Fe(fcz)2Cl2]-2CH30H with fez = l-(2,4-difluorophenyl)-l,l-bis[(l//-l,2,4-triazol-l-yl)methyl]ethanol which catalyzed the oxidation of benzyl alcohol to benzaldehyde with hydrogen peroxide as oxidant in 87% yield and up to 100% selectivity [149]. An alternative approach is based on the use of heteropoly acids, whereby the incorporation of vanadium and iron into a molybdo-phosphoric acid catalyst led to high yields for the oxidation of various alcohols (up to 94%) with molecular oxygen [150]. 

Pamukcu S, Hannum L, Wittle KJ. (2008). Delivery and activation of nano-iron by DC electric field./owraa/ of Environmental Science and Health A43 934-944. 

Leventis N, Chandrasekaran N, Sotiriou-Leventis C., Mumtaz A (2009) Smelting in the age of nano Iron aerogels. J Mater Chem 19 63-65. 

Free nano-iron has been reported as an oxidation catalyst for the oxidation of benzyl alcohol applying hydrogen peroxide as the oxidant [142]. Although the turnover number based on iron is only modest (TON around 30), the high selectivity... 

At high-temperature, initial growth of particle is rapid, the particle size distribution has become very wide, the crystal growth activation energy increases to 175kJ mol" which mean nano-iron crystal strengthens its self-spread ability at the edge of coarse particles. 

Module 2 Using nanoscale bimetallic iron particles for groundwater remediation. This module has been created according to existing literature. Trichloroethylene (TCE), one of the most ubiquitous soil and groundwater contaminants, is used as a sample contaminant. The reductive dehalogenation of TCE via zero-valent nano iron particles can be described by the following equation (29) ... 

Refill the separatory furmel as necessary until all 500 mL of the sodium borohydride solution has been consitmed. The initial color of the ferric chloride solution is rasty, which will go to tight green (ferric to ferrous) and eventually to black (ferric to zero valent i.e., Fe°) as the nano iron crystals are formed. 

Let the mixture settle for about 45 min and decant the supernatant when the small gas bubbles have almost disappeared. Use the nano iron crystal slurry located at the bottom of the beaker immediately for Module 2. 

In the synthesis of nano iron, iron is reduced from iron (III) to elemental iron. What is used as the reducing agent ... 

What gas is evolved during the synthesis of nano irons ... 

The discovery, through serendipity, that the combustion of iron hydrazine carboxylate yields nano-iron oxide led to the preparation of various nanosize oxide materials by the thermal reactivity of metal hydrazine carbox-ylates. Hitherto, oxide materials prepared by conventional ceramic techniques used hydroxides, carbonates, nitrates, or oxalates as starting materials. The procedure involves their repeated pulverization and... 

Fig. 15-5 Comparative adsorption of several metals onto amorphous iron oxyhydroxide systems containing 10 M Fej and 0.1 m NaNOs. (a) Effect of solution pH on sorption of uncomplexed metals, (b) Comparison of binding constants for formation of soluble Me-OH complexes and formation of surface Me-O-Si complexes i.e. sorption onto Si02 particles, (c) Effect of solution pH on sorption of oxyanionic metals. (Figures (a), (c) reprinted with permission from Manzione, M. A. and Merrill, D. T. (1989). "Trace Metal Removal by Iron Coprecipitation Field Evaluation," EPRI report GS-6438, Electric Power Research Institute, California. Figure (b) reprinted with permission from Balistrieri, L. et al. (1981). Scavenging residence times of trace metals and surface chemistry of sinking particles in the deep ocean, Deep-Sea Res. 28A 101-121, Pergamon Press.)...

The Mossbauer effect, discovered by Rudolf L. Mossbauer in 1957, can in short be described as the recoil-free emission and resonant absorption of gamma radiation by nuclei. In the case of iron, the source consists of Co, which decays with a half-life of 270 days to an excited state of Fe (natural abundance in iron 2%). The latter, in turn, decays rapidly to the first excited state of this isotope. The final decay generates a 14.4 keV photon and a very narrow natural linewidth of the order of nano eV. 

Based on the attenuation of the iron 2p signal and assuming a mean free path for the iron electrons of 1.5 to 2 nanometers, it is estimated that the carbon overlayer is at least 1.8 to 2.5 nano-... 

George, S. et al. (2010) Use of a rapid cytotoxicity screening approach to engineer a safer zinc oxide nanoparticle through iron doping. ACS Nano, 4 (1), 15-29. 

Lin, Y., Weng, C. and Chen, F. (2008) Effective removal of AB24 dye by nano/ micro-size zero-valent iron. Separation and Purification Technology, 64, 26-30. Wang, C.B. and Zhang, W.X. (1997) Synthesizing nanoscale iron particles for rapid and complete dechlorination of TCE and PCBs. Environmental Science and Technology, 31, 2154-2156. 

Varanasi, P., Fullana, A. and Sidhu, S. (2007) Remediation ofPCB contaminated soils using iron nano-particles. Chemosphere, 66, 1031-1038. 

Liao, C.J., Chung, T.L., Chen, W.L. and Kuo, S.L. (2007) Treatment of pentachlorophenol-contaminated soil using nano-scale zero-valent iron with hydrogen peroxide. Journal of Molecular Catalysis A Chemical, 265, 189—194. 

Kanel, S.R., Greneche, J.M. and Choi, H. (2006) ArsenicfV) removal from groundwater using nano scale zero-valent iron as a colloidal reactive barrier material. Environmental Science and Technology, 40, 2045—2050. 

Bahome, M., Jewell, L., Hildebrandt, D., Glasser, D., and Coville, N. J. 2005. Fischer-Tropsch synthesis over iron catalysts supported on carbon nano tubes. Applied Catalysis A General 287 60-67. 

A Continuous Process for Separation of Wax from Iron Nano-Catalyst Particles by Using Cross-Flow Filtration... 

A continuous cross-flow filtration process has been utilized to investigate the effectiveness in the separation of nano sized (3-5 nm) iron-based catalyst particles from simulated Fischer-Tropsch (FT) catalyst/wax slurry in a pilot-scale slurry bubble column reactor (SBCR). A prototype stainless steel cross-flow filtration module (nominal pore opening of 0.1 pm) was used. A series of cross-flow filtration experiments were initiated to study the effect of mono-olefins and aliphatic alcohol on the filtration flux and membrane performance. 1-hexadecene and 1-dodecanol were doped into activated iron catalyst slurry (with Polywax 500 and 655 as simulated FT wax) to evaluate the effect of their presence on filtration performance. The 1-hexadecene concentrations were varied from 5 to 25 wt% and 1-dodecanol concentrations were varied from 6 to 17 wt% to simulate a range of FT reactor slurries reported in literature. The addition of 1-dodecanol was found to decrease the permeation rate, while the addition of 1-hexadecene was found to have an insignificant or no effect on the permeation rate. 

Separation of Wax from Iron Nano-Catalyst Particles... 

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