10 documents found, page 1 of 1

Controlled formation of reactive Fe particles dispersed in a carbon matrix acti...

In this work, reactive iron nanoparticles dispersed in a carbon matrix were produced by the controlled thermal decomposition of Fe3+ ions in sucrose. During the sucrose decomposition, the Fe3+ ions are reduced to form iron nanometric cores dispersed in a porous carbonaceous matrix. The materials were prepared with iron contents of 1, 4, and 8 wt.% and heated at 400, 600, and 800 °C. Analyses by X-ray diffractio...

Use of iron and bio-oil wastes to produce highly dispersed Fe/C composites for ...

This work describes the synthesis, characterization, and application of an active heterogeneous photo-Fenton system obtained from two different wastes, i.e., laterite (an iron mining waste) and the acid aqueous fraction (AAF) from bio-oil production. AAF with high acidity (ca. 3 molH+ L−1) and organic concentration (25 wt.%) obtained from biomass flash pyrolysis was used for the efficient extraction of Fe3+ fro...

INFLUÊNCIA DO TEOR DE AUSTENITA REVERSA NA CORROSÃO DO AÇO SUPERMARTENSÍTICO

Aços supermartensíticos tem sido amplamente aplicados em indústrias, especialmente no setor de petróleo e gás, devido à boa relação custo benefício que apresentam. São aços inoxidáveis martensíticos com teores de cromo entre 11 e 13% em massa, baixo teor de carbono intersticial e adições de níquel, molibdênio e em alguns casos, titânio e nióbio. Através de tratamentos térmicos de têmpera e revenimento, as propr...

Effect of tetramethylammonium hydroxide on nucleation, surfacemodification and ...

Nanoparticles of magnetite (Fe3O4) were obtained by reacting ferric chloride with sodium sulphite, through the reductionprecipitation method. The effects of adding tetramethylammonium hydroxide (TMAOH) during or after the precipitation of the iron oxide were studied in an attempt to obtain well-dispersed magnetite nanoparticles. Accordingly, the following experimental conditions were tested: (i) precipitation i...

Preparation of composite with silica-coated nanoparticles of iron oxide spinels...

It is reported a novel method to prepare magnetic core (iron oxide spinels)–shell (silica) composites containing well-dispersed magnetic nanoparticles in aqueous solution. The synthetic process consists of two steps. In a first step, iron oxide nanoparticles obtained through co-precipitation are dispersed in an aqueous solution containing tetramethylammonium hydroxide; in a second step, particles of this sample...

Catalytic carbon deposition-oxidation over Ni, Fe and Co catalysts : a new indi...

In this work, a new two-step route to store and transport associated natural gas, promoted by Ni, Fe and Co supported catalyst was presented. Initially, CH4 is converted into carbon deposits (M/C composite), being Fe catalyst the most active catalyst. In Step 2, M/C composite reacts with H2O producing H2, CO and CH4. TPO experiments showed that efficiency and selectivity of oxidation depends on the metal. Ni ca...

Production of nanostructured magnetic composites based on Fe0 nuclei coated wit...

In this work, a catalytic CVD process using ethanol as carbon source was used to convert an iron rich waste, i.e. red mud (RM), in a magnetic composite. TPCVD (temperature programmed CVD), XRD, Mössbauer, EDS, magnetic measurements, TG/DTA, CHN, BET, Raman, SEM and TEM showed that ethanol gradually reduces the iron phases in the RM to Fe3O4 at 500 ◦C and to Fe1−xO at 600 ◦C. At higher temperatures Fe0 and Fe ca...

Facile preparation of carbon coated magnetic Fe3O4 particles by a combined redu...

In this work, we report a simple method for the preparation of magnetic carbon coated Fe3O4 particles by a single step combined reduction of Fe2O3 together with a Chemical Vapor Deposition process using methane. The temperature programmed reactionmonitored by Mo¨ ssbauer, X-ray Diffraction and Raman analyses showed that Fe2O3 is directly reduced by methane at temperatures between 600 and 900 8C to produce mainl...

Synthesis, spectroscopic characterization and x-ray structures of five-coordina...

Mineralogy and trace-element geochemistry of the high-grade iron ores of the Ág...