4,4′-Bipyridyl complexes of iron: Magnetic, Mössbauer and other spectroscopic studies

4,4prime-Bipyridyl (4,4prime-bipy) complexes of ferrous salts of the Fe(4,4prime-bipy)x(anion)y type (where x or y=1 or 2) and of ferric salts of the Fe(4,4prime-bipy)m(anion)n type (where m=1 or 2 and n=3) have been synthesised. Elemental analyses, i.r. and electronic spectra, magnetic and Mössbauer studies have been performed to characterize the complexes. 4,4prime-Bipy and some anions are inferred to act as bridging ligands. The magnetic moments, electronic and Mössbauer spectra suggest that the complexes are of high spin type with distorted octahedral structures. The value of the isomer shift and quadrupole splitting are discussed in terms of bonding of the ligand and anions.

Biosorption of iron(III) from aqueous solutions using the husk of Cicer arientinum

Iron is a major pollutant released as a by-product during several industrial operations especially during acid mining of metal ores. In this paper, the use of Bengal gram husk (husk of channa dal, Cicer arientinum) in the biosorption of Fe(III) from aqueous solutions is discussed. Parameters like agitation time, adsorbent dosage and pH were studied at different Fe(Ill) concentrations. The adsorption data fit well with Langmuir and Freundlich isotherm models. The adsorption capacity (q(max)) calculated from the Langmuir isotherm was 72.16 mg of Fe(III)/g of the biosorbent at an initial pH of 2.5. Desorption Studies were performed at different concentrations of hydrochloric acid showing that quantitative recovery of the metal ion is possible. The infrared spectra of the biomass before and after treatment with Fe(III), revealed that hydroxyl, carboxyl and amide bonds are involved in the uptake of Fe(III) ions.

Complexes of lanthanide nitrates with N,N-diethylantipyrine-4-carboxamide

New complexes of lanthanide nitrates with N, N-diethylantipyrine-4-carboxamide (DEAP), with the general formulae [Ln2(DEAP)3] [NO3]6 (where Ln = La, Pr, Nd, Sm, Tb, Ho, Er, Yb and Y) have been isolated and characterized by chemical analysis and various physical methods such as electrolytic conductance, IR and13C NMR spectral data. Electrolytic conductance values and infrared spectral studies indicate that the nitrate groups are coordinated. Infrared and13C NMR spectral analysis show that the ligand DEAP is coordinated to the tripositive metal ion through the diethylcarboxamide carbonyl and antipyrine carbonyl oxygens in a bidentate fashion.

Complexes of lanthanide nitrates with O,O′,N-triisopropyl phosphoramidate

A substituted phosphoramidate has been used as a ligand to lanthanides for the first time. New complexes of lanthanide nitrates with O,O′,N-triisopropyl phosphoramidate (TIP) of the general formula Ln(TIP)3(NO3)3 where Ln=La-Yb and Y have been synthesised and characterised by chemical analysis, infrared and visible electronic spectra and electrical conductance.Infrared spectra indicate the coordination of the ligand to the metal ions through the oxygen of the P=O group. IR and conductance show that the nitrate groups are all coordinated. Electronic spectral shapes have been interpreted in terms of an eight coordinate geometry around the metal ions.

Charred seeds in Mikkeli Orijärvi : A study of subsistence strategies of an Iron Age settlement in East Finland

In this study the over 350 macrofossil samples, containing over 2300 charred plant remains from an Iron Age settlement containing fossil fields in Mikkeli Orijärvi Kihlinpelto, were studied archaeobotanically. The aim was to get more information about subsistence strategies, especially agriculture and study differences in the plant combinations in the different structures and use the archaeobotanical theory to interpret these structures. The methodological question was to study the taphonomy of the charred plant material. The results gave a diverse impression of the agriculture and subsistence strategies of the settlement in Orijärvi, where barley was the most important cereal with rye, wheat and oat cultivated as minor crops. The arable weed assemblage indicates that the fields were situated in different kinds of soils and the crops were cultivated when different kind of weather conditions were prevailing. Ergot was found with the cereals, and it was growing on some of the arable crops and it also indicates wet climate. Hemp and flax were cultivated and wild plants were collected. The meadow and wetland plants found in the material derive most probably from animal fodder. Tubers of bulbous oat-grass were interesting, because they are usually found in graves. Comparison with other Iron Age settlements and graves indicates that the plant material found from the ancient field layers derives most probably from dwellings and graves, which were taken into cultivation.

Zeta Potential Studies On Some Iron-Ore Minerals In The Presence Of Starches

Authors perform zeta potential studies on hematite, corundum, and quartz samples using starches to understand the adsorption behavior of polymeric starch flocculants at the oxide mineral-solution interface and to correlate this information with their flocculation characteristics and investigate effects of pH and CaCl#72 on zeta potential of Fe ore minerals.

A convenient and high-yield synthesis for pyridinium and metal hexafluorocomplexes of vanadium, chromium, iron and cobalt

Pyridinium poly(hydrogen fluoride) reacts with the oxide of vanadium(V) and chlorides of chromium(III), iron (III) and Co(II) at room temperature forming the pyridinium salts of hexafluoro vanadate(V), hexafluorochromate(III), hexafluoroferrate(III) and hexafluorocobaltate(II) in near quantitative yields (80%). These pyridinium salts are the precursors for the preparation of the alkali metal hexafluorometallates by metathetic reactions in acetonitrile medium with the corresponding metal chlorides. The prepared salts have been identified by their infrared spectral data and elemental analysis.

Wire-cylinder corona discharge with the wire at positive potential studies of iron oxides

A wire-cylinder corona discharge was studied in nitrogen and dry air in crossed electric and magnetic fields for values of magnetic field ranging from 0 to 3000 G with the wire at positive potential. In the absence of a magnetic field pre-onset streamers and pulses were observed in nitrogen. In both nitrogen and dry air breakdown streamers were observed just before spark breakdown of the gap. Furthermore, experiments in dry air at atmospheric pressure in an electric field indicate regular pre-onset streamers appearing at time intervals of 19.5 µs. The appearance of regular pre-onset streamers suggests that it is not possible for negative ions to form a sheath close to the anode as postulated by Hermstein (1960) for the formation of steady or glow corona in a point-plane gap.

Structure and thermal stability relationships in ring-substituted arylammonium nitrates

The thermal stability of ring-substituted arylammonium nitrates has been investigated using thermal methods of analysis. The decomposition temperature of meta- and para-substituted derivatives is found to be linearly related to the Hammett substituent constant σ. The activation energy for decomposition determined by isothermal gravimetry increases with the increasing basicity of the corresponding amine. The results suggest that the primary step in the decomposition process of these salts is proton abstraction by the anion from the arylammonium ion.

Open-circuit potential—time transients of alkaline porous iron electrodes at various states-of-charge

Open-circuit potential—time transients during the discharge of alkaline porous iron electrodes at various states-of-charge have been studied. From this, it has been possible to arrive at a correlation between the parameters of self-discharge kinetics of the electrode and observed open-circuit potential—recovery time constants. The study provides a method of estimate the state-of-charge of the rechargeable iron electrodes. As a hydrogen evolution reaction inevitably occurs on alkaline iron electrodes, the kinetics of the reaction have also been investigated.