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Elemental Iron (elemental + iron)
Selected AbstractsReductive transformation of hexahydro-1,3,5-trinitro-1,3,5-triazine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine, and methylenedinitramine with elemental ironENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2005Seok-Young Oh Abstract Reductive (pre)treatment with elemental iron is a potentiallyuseful method for degrading nitramine explosives in water and soil. In the present study, we examined the kinetics, products, and mechanisms of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) degradation with elemental iron. Both RDX and HMX were transformed with iron to formaldehyde, NH, N2O, and soluble products. The yields of formaldehyde were relatively constant (71% ± 5%), whereas the yields of NH and N2O varied, depending on the nitramine and the mechanism. The reactions most likely were controlled by a surface process rather than by external mass transfer. Methylenedinitramine (MDNA) was an intermediate of both RDX and HMX and was transformed quantitatively to formaldehyde with iron. However, product distributions and kinetic modeling results suggest that MDNA represented a minor reaction path and accounted for only 30% of the RDX reacted and 14% of the formaldehyde produced. Additional experiments showed that RDX reduction with elemental iron could be mediated by graphite and Fe2+ sorbed to magnetite, as demonstrated previously for nitroaromatics and nitrate esters. Methylenedinitramine was degraded primarily through reduction in the presence of elemental iron, because its hydrolysis was slow compared to its reactions with elemental iron and surface-bound Fe2+. Our results show that in a cast iron-water system, RDX may be transformed via multiple mechanisms involving different reaction paths and reaction sites. [source] EFFECT OF PACKAGING MATERIALS ON THE QUALITY OF IRON-FORTIFIED WHOLEMEAL FLOUR DURING STORAGEJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2007N. HUMA ABSTRACT The effect of packaging materials on the physicochemical and rheological characteristics of iron-fortified wholemeal flour (WMF) during storage was determined. WMF was fortified with three fortificants, namely ferrous sulfate (30 ppm), ferrous sulfate + ethylenediamine tetraacetic acid (EDTA) (20 + 20 ppm) and elemental iron (60 ppm). Each flour was also fortified with 1.5 ppm folic acid. Moisture, flour acidity and peroxide value increased during storage, while protein and fat contents decreased. Highest conversion of Fe2+ into Fe3+was observed in flour fortified with ferrous sulfate (2.72%), followed by that fortified with ferrous sulfate + EDTA (1.49%) and elemental iron (1.06%). Water absorption and dough viscosity of iron-fortified flours increased during storage. The flour containing ferrous sulfate was most acceptable regarding sensory characteristics, followed by samples containing ferrous sulfate + EDTA. Fortified flours were more stable during storage than unfortified. Addition of EDTA increased the stability of flours and fortificants. The fortified flours stored in polypropylene bags proved more stable than those stored in the tin boxes. PRACTICAL APPLICATIONS The main role of packaging is to protect the product during handling, distribution and storage against environmental and mechanical hazards. The success of a fortification program depends on the stability of micronutrients and food to which these are added. Chemical changes during storage badly affect chapatti making and sensory properties. Exposure of the fortificant to any factor including heat, moisture, air or light, and acid or alkaline environments during processing, packaging, distribution, or storage affects its stability. Flour containing elemental iron and ferrous sulfate with EDTA remained stable up to 42 days. The unfortified flour and flour containing ferrous sulfate remained stable for 21 days in tin boxes and 28 days in the polypropylene bags. Wheat flour milling industry would be benefited from this research if government is keen to launch iron fortification program in the country to curb iron deficiency anemia among population. [source] EFFECT OF MINERAL FORTIFICATION ON RHEOLOGICAL PROPERTIES OF WHOLE WHEAT FLOURJOURNAL OF TEXTURE STUDIES, Issue 1 2009SAEED AKHTAR ABSTRACT This study was aimed to evaluate the rheological changes that take place in the dough as a result of addition of elemental iron, ferric sodium ethylenediaminetetraacetate, zinc sulphate and zinc oxide in various combinations to whole wheat flour (WWF), packaged in polypropylene woven bags and tin boxes and stored for a period of 60 days under ambient and controlled conditions of temperature and relative humidity. Water absorption (WA) capacity, dough development time (DDT) and dough stability time (DS) of the fortified WWF were measured by farinographic method, and peak viscosity was assessed by viscographic analyses. WA capacity and DDT of flours increased during storage. Fortification significantly (P < 0.05) affected WA, DDT, DS and viscographic characteristics of the flours. Packaging materials (P < 0.05) influenced WA, DDT and DS, while storage condition had only affected viscographic properties of the flours. PRACTICAL APPLICATIONS The success of any fortification program depends on the stability of micronutrients and food to which they are added. Exposure of the fortificants to any of the physical and chemical factors including heat, moisture, air, or light and acid or alkaline environments during food processing, packaging, distribution or storage affects their stability. The rheological properties of dough made from fortified flours determine the quality of the fortified end product. Changes in rheological properties as a result of the incorporation of fortificants in the flour, its storage under variable conditions and length of time might have an effect on quality, cost and nutrition of the product. [source] Mechanochemical Formation of Metal,Ceramic CompositesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2000Nicholas J. Welham A mechanical activation technique has been used to form composites of alumina with titanium carbide, nitride, or carbonitride, both with and without elemental iron. The composites were formed by reacting elemental aluminum with either ilmenite (FeTiO3) or rutile (TiO2) concentrates in the presence of carbon and/or nitrogen in a ball-mill at ambient temperature. The reaction was complete for the ilmenite samples after milling but was completed only for rutile under hot pressing conditions. Microhardness measurements indicated that the composites had hardnesses in the range 19,30 GPa (1740,2750 VHN), with only a small variation within each sample. Elemental mapping of the pressed pellets indicated that titanium and aluminum were evenly distributed on a submicrometer level whereas iron tended to coalesce into <20 ,m particles in the presence of TiC. The coalescence decreased with the carbon content of the hard material until iron was evenly distributed with TiN. A superstoichiometric amount of aluminum led to the formation of iron,aluminum phases which decreased the iron coalescence. The XRD crystallite size of the alumina was 30,50 nm and was 25,50 nm for the titanium phases, confirming the extremely fine microstructure. [source] | ||||||||||