Search results for "iron [calorimeter]"

Voltammetric analysis of iron oxide pigments

2002

Eighteen earthy and four pure synthetic pigments containing alpha-Fe2O3 (hematite), alpha-FeOOH (goethite) and poorly crystalline Fe and Mn oxide species were analyzed by voltammetry of microparticles. Three natural samples were subjected to an interlaboratory test to evaluate the reproducibility of the voltammetric peak potentials and peak shapes. The results confirmed that linear-sweep voltammetry is able to distinguish between poorly crystalline, ferrihydrite-like oxides and well-crystalline hematite and goethite and to detect XRD-amorphous Mn(III,IV) oxides via the peak occurrence. Voltammetry is further able to distinguish between pigments containing well-crystalline goethite (accordin…

Adsorption of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) by goethite.

2014

Interaction between the goethite surface and 4-chloro-2-methylphenoxyacetic acid (MCPA) herbicide was studied using density functional theory (DFT) calculations combined with molecular dynamics (MD). The important step made here lies in the use of a periodic DFT method enabling the study of a mineral surface of different protonation states, in strong contrast with previous molecular modeling studies limited to single protonation state corresponding to the point of zero charge. Different surface OH groups and MCPA proton states were used to mimic the strong effects of pH on the outer- and inner-sphere surface complexes that are theoretically possible, together with their binding energies, an…

Front Cover: Iron-Catalyzed C−O Bond Activation: Opportunity for Sustainable Catalysis (ChemSusChem 20/2017)

2017

Iron-Catalyzed C−O Bond Activation: Opportunity for Sustainable Catalysis

2017

Oxygen-based electrophiles have emerged as some of the most valuable cross-coupling partners in organic synthesis due to several major strategic and environmental benefits, such as abundance and potential to avoid toxic halide waste. In this context, iron-catalyzed C-O activation/cross-coupling holds particular promise to achieve sustainable catalytic protocols due to its natural abundance, inherent low toxicity, and excellent economic and ecological profile. Recently, tremendous progress has been achieved in the development of new methods for functional-group-tolerant iron-catalyzed cross-coupling reactions by selective C-O cleavage. These methods establish highly attractive alternatives t…

States of Division: Border and Boundary Formation in Cold War Rural Germany, by Sagi Schaefer

2017

La boucherie et les sacrifices bovins en Gaule aux IIe et Ier siècles avant notre ère

2007

Piles of animal bones from large domesticates – cattle and horses – have been identified on various settlement sites in Gaul ; these have undergone practices readily distinguishable from domestic butchery. Already perceptible on rural sites, these indications of a special butchery regime for cattle become more and more apparent elsewhere in tandem with the increasingly urbanised character of settlements. Cattle was also sacrificed during the Iron Age at sanctuaries, but only a small proportion of the meat produced was consumed in banquets held on site. At the Titelberg oppidum, substantial quantities of cattle bones were piled up around the sanctuaries at the end of the Iron Age and at the …

Study of the phase composition of iron-containing Langmuir-Blodgett layers before and after thermal and chemical treatment

1992

Iron-containing Langmuir–Blodgett mono- and multilayers were prepared by depositing ferric stearate onto silicon wafers. Particular care should be taken in order to avoid the presence of alkali ions, which may replace iron ions in the deposited film. By a subsequent heating in air, the fatty acid chains were thermodesorbed. This results in a rather homogeneous coating of the samples by an iron oxide, most probably in the form of crystalline and amorphous γ-FeOOH, as found by conversion electron Mossbauer, photoelectron and microprobe studies. By a subsequent heating in hydrogen gas or exposure to nascent hydrogen, a partial reduction of the iron oxide layer is possible up to the metallic st…

Metallic lead recovery from lead-acid battery paste by urea acetate dissolution and cementation on iron

2009

Abstract A suitable hydrometallurgical and environmentally friendly process was studied to replace the currently used practices for recycling lead-acid batteries via smelting. Metallic lead was recovered by cementation from industrial lead sludge solutions of urea acetate (200 to 500 g/L) using different types of metallic iron substrates (nails, shaving or powder) as reducing agents. Under specific operating conditions, up to 99.7% of lead acid battery paste, mainly composed of PbSO4, PbO2 and PbO·PbSO4 species, was converted to metallic lead.. The conversion of the metallic lead and rate of the cementation reaction were strictly dependent on the type of iron substrate used as the reductant…

Size-isolation of superparamagnetic iron oxide nanoparticles improves MRI, MPI and hyperthermia performance.

2020

Journal of nanobiotechnology 18, 22 (2020). doi:10.1186/s12951-020-0580-1

Quantitative colorimetric-imaging analysis of nickel in iron meteorites.

2011

A quantitative analytical imaging approach for determining the nickel content of metallic meteorites is proposed. The approach uses a digital image of a series of standard solutions of the nickel-dimethylglyoxime coloured chelate and a meteorite sample solution subjected to the same treatment as the nickel standards for quantitation. The image is processed with suitable software to assign a colour-dependent numerical value (analytical signal) to each standard. Such a value is directly proportional to the analyte concentration, which facilitates construction of a calibration graph where the value for the unknown sample can be interpolated to calculate the nickel content of the meteorite. The…