نتایج جستجو برای: keywords different iron oxides fractions
تعداد نتایج: 3584631 فیلتر نتایج به سال:
Iron–nickel spinel oxide NiFe2O4 nanoparticles have been prepared by the combination of chemical precipitation and subsequent mechanical milling. For comparison, their analogue obtained by thermal synthesis is also studied. Phase composition and structural properties of iron–nickel oxides are investigated by X-ray diffraction and Mössbauer spectroscopy. Their catalytic behavior in methanol deco...
Matching biosolids application rates to crop phosphorus (P) needs requires quantifying the P fertilizer replacement value of biosolids. Neutral ammonium citrate (NAC) extraction of P, used for assessing available P in mineral fertilizers, was evaluated for 35 different biosolids. Biosolids NAC-P was not statistically different (p 1⁄4 0.05) from total P using strong acid digestion (EPA 3051-P). ...
Shahid Nilchian (Dopelan) deposit, located in high mountains of Chahar-Mahal Bakhtiari Province within the Zagros Thrust structural unit, is one of the main bauxite and argillite deposits of Iran. Many highly folded and faulted sedimentary successions are cropped in the area. The bauxite of Shahid Nilchian deposit is of lateritic type and belongs to Permo-Triassic in age. Five bauxite types wit...
A soil washing study was performed to evaluate the treatability of New River sand contaminated in the laboratory with a petroleum distillate. Unaltered and base-extracted sands were mixed with petroleum hydrocarbons, equilibrated, and washed with water or a surfactant at two different pH values (7 and 12). The surfactant had no significant effect on contaminant removal efficiencies at neutral p...
The concentrations of the rare earth elements (REE) in surface waters and sediments, when normalized on an elementby-element basis to one of several rock standards and plotted versus atomic number, yield curves that reveal their partitioning between different sediment fractions and the sources of those fractions, for example, between terrestrial-derived lithogenous debris and seawater-derived b...
Our understanding of the complex aqueous chemistry of iron in natural systems has advanced significantly over recent years. Here we will highlight how new contributions from nanogeoscience combine with conventional aqueous geochemistry to provide a novel view of kinetics in the modern iron biogeochemical cycle, and the evolution of the iron cycle through geologic time. We start by considering t...
The steadfast rule of a ferromagnetic hysteresis loop claims its saturation positioned within the first and third quadrants, whereas its saturation positioned in the second and fourth quadrants (named as self-reversed magnetic hysteresis) is usually taken as an experimental artifact and is always intentionally ignored. In this report, a new insight in this unique hysteresis phenomenon and its m...
Information about forms of zinc (Zn) is important for the evaluation of its status in soil and also understanding of the soil fertility and chemistry. To obtain such information, amounts and distribution of Zn in different fractions of 20 soil samples of Tehran province, Iran were determined by sequential extraction method and their relationships with each other and with soil characteristics we...
Information about forms of zinc (Zn) is important for the evaluation of its status in soil and also understanding of the soil fertility and chemistry. To obtain such information, amounts and distribution of Zn in different fractions of 20 soil samples of Tehran province, Iran were determined by sequential extraction method and their relationships with each other and with soil characteristics we...
An existing sequential extraction scheme for particulate iron (Fe) is evaluated manganese (Mn) using a range of Mn standards. The consists 5 steps and quantifies operationally defined pools (1) poorly ordered oxides phosphates (ascorbic acid extractable); (2) carbonates sulfides (1 M HCl extractable), (3 4) crystalline (citrate buffered dithionite ammonium oxalate extractable, respectively) (5)...
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