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Hypothesis:
The use of immobilized enzyme-type biocatalysts to mimic specific processes in soil can be considered one of the most promising alternatives to overcome the difficulties behind the structural elucidation of riverine humic-derived iron-complexes. Herein, we propose that the immobilization of the functional mushroom tyrosinase, Agaricus...
The low solubility of inorganic iron(III) in seawater leads to very limited availability of this important micronutrient for marine organisms. Estuarine or oceanic iron is almost entirely bound to organic ligands of mainly unknown chemical structure. In this context, riverine input of iron rich, land-derived dissolved organic matter (DOM) can play...
Organic soils in the Arctic-boreal region produce small aquatic humic ligands (SAHLs), a category of naturally occurring complexing agents for iron. Every year, large amounts of SAHLs-loaded with iron mobilized in river basins-reach the oceans via river runoff. Recent studies have shown that a fraction of SAHLs belong to the group of strong iron-bi...
In peatlands, bacterial tyrosinases (TYRs) are proposed to act as key regulators of carbon storage by removing phenolic compounds, which inhibit the degradation of organic carbon. Historically, TYR activity has been blocked by anoxia resulting from persistent waterlogging; however, recent events of prolonged summer drought have boosted TYR activity...
The present study elucidates the role of natural iron fertilization of the coastal ocean by so-called “blackwater rivers”. Areas of marsh, fen, peatland, boreal forest etc. are characterized by organic-rich soils. From those soils, humic substances (humic and fulvic acids) are leached to the aquatic system resulting in river water that is low in pH...
The use of ionic liquids for micro-extraction of metals has been popularized during the last decades. The main drawback for this application of ILs is leaching into the sample. Hollow fiber liquid phase micro-extraction might be a promising approach due to the immobilization of the ILs during the extraction process.
Herein, we evaluate the abilitie...
A series of β-O-4 type dilignols and their iron(III) complexes, designed as model compounds for humic acids, were prepared and characterized by ¹H-NMR and ¹³C-NMR spectroscopy, elemental analysis, EPR, IR and UV-Vis spectroscopies and electrospray ionization mass spectrometry (ESI-MS). Properties regarding iron binding, stability, lipophilicity and...
Land-derived dissolved organic matter (DOM) is able to transport iron and other trace metals from natural organic matter (NOM)-rich areas like peat bogs via rivers to the open ocean and therefore plays a pivotal role in the iron supply of coastal marine organisms Iron is distributed over all DOM size-fractions and predominantly found in large clust...
We studied the extraction behavior of two thioglycolate-based ionic liquids (ILs), for heavy metals from aqueous solutions; substances of interest were methyltrioctylammonium S-hexyl thioglycolate [N1888][C6SAc] and methyltrioctylphosphonium S-hexyl thioglycolate [P1888][C6SAc]. Theses ILs previously have shown very good extraction abilities toward...
A total of 77 specimens of the mallard Anas platyrhynchos were sampled from the eastern part of Austria before the ban on lead gun shot for hunting water fowl. Samples of muscle and liver were analyzed for their content of Cr, Cu, Zn, Ag, Cd, Hg and Pb using atomic absorption spectrometry. In addition the Hg content of feather samples from this aqu...
A series of monomeric and dimeric Fe(III) complexes with O,O-; O,N-; O,S-coordination motifs has been prepared and characterized by standard analytical methods in order to elucidate their potential to act as model compounds for aquatic humic acids. Due to the postulated reduction of iron in humic acids and following uptake by microorganisms, the re...
Eight novel task-specific ionic liquids (TSILs) based on the thioglycolate anion designed for heavy metal extraction have been prepared and characterized by ¹H and ¹³C NMR, UV-Vis, infrared, ESI-MS, conductivity, viscosity, density and thermal properties. Evaluation of their time-resolved extraction abilities towards cadmium(II) and copper(II) in a...
Iron is a micronutrient of particular interest as low levels of iron limit primary production of phytoplankton and carbon fluxes in extended regions of the world's oceans. Sphagnum-peatland runoff is extraordinarily rich in dissolved humic-bound iron. Given that several of the world's largest wetlands are Sphagnum-dominated peatlands, this ecosyste...
Humic substances (HS) are important iron chelators responsible for the transport of iron from freshwater systems to the open sea, where iron is essential for marine organisms. Evidence suggests that iron complexed to HS comprises the bulk of the iron ligand pool in near-coastal waters and shelf seas. River-derived HS have been investigated to study...
Supplementary
Supplementary
Humic substances (HS) are important iron chelators responsible for the transport of iron from freshwater systems to the open sea, where iron is essential for marine organisms. Evidence suggests that iron complexed to HS comprises the bulk of the iron ligand pool in near-coastal waters and shelf seas. River-derived HS have been investigated to study...
A series of monomeric and dimeric FeIII complexes bearing benzoic hydroxamates as O,O-chelates has been prepared and characterized by elemental analysis, IR spectroscopy, UV-Vis spectroscopy, electrospray ionization mass spectrometry (ESI-MS), cyclic voltammetry, EPR spectroscopy and for some examples by X-ray diffraction analysis. The stability of...
This study aims to develop novel ammonium and phosphonium ionic liquids (ILs) with thiosalicylate (TS) derivatives as anions and evaluate their extracting efficiencies towards heavy metals in aqueous solutions. Six ILs were synthesized, characterized, and investigated for their extracting efficacies for cadmium, copper, and zinc. Liquid-liquid extr...
Iron is an essential micronutrient for all marine organisms, but it is also a growth limiting factor as the iron concentrations in the open ocean are below 1 nmol L(-1) . At high chloride concentrations present in sea water, iron is almost entirely bound to organic ligands of the dissolved organic matter fraction, which are mostly of unknown struct...
The speciation of iron(III) in oxic seawater is dominated by its hydrolysis and sedimentation of insoluble iron(III)-oxyhydroxide. As a consequence, many oceanic areas have very low iron levels in surface seawater which leads to iron deficiency since phytoplankton require iron as a micronutrient in order to grow. Fortunately, iron solubility is not...
Two novel maltol-based ionic liquids, namely [A336][Mal] and [C101][Mal], were synthesized as potential extracting agents for radionuclides from water. These two room temperature task-specific ionic liquids could be easily prepared by anion metathesis starting from commercially available materials. The isolated compounds were characterized by stand...
During summer 2011, samples of sediment, macrophytes, and fish tissues from the shallow, slightly alkaline Lake Neusiedl, Austria, were evaluated for their total Hg content. This is the first report of Hg levels from this lake. Sediments displayed Hg contents between 0.025 and 0.113 μg g−1 dw (dry weight), significantly correlating with the proport...
Two multinuclear complexes [Fe6(μ3-O)2(μ4-O2)L10(OAc)2(H2O)2]·2.625Et2O·2.375H2O () and [Fe(III)11Cl(μ4-O)3(μ3-O)5L16(dmf)2.5(H2O)0.5]·Et2O·1.25dmf·3.8H2O (), where HL = 3,4,5-trimethoxybenzoic acid and dmf = dimethylformamide, have been prepared from trinuclear iron(iii) carboxylates via their structural rearrangement in dimethylformamide or dieth...
Samples from a pristine raised peat bog runoff in Austria, the Tannermoor creek, were analysed for their iron linked to natural organic matter (NOM) content. Dissolved organic carbon < 0.45 μm (DOC) was 41-64 mg L(-1), iron 4.4-5.5 mg L(-1). Samples were analysed applying asymmetric field flow fractionation (AsFlFFF) coupled to UV-vis absorption, f...
Between May and September 2011 a total of 361 samples from water, sediment, macrophytes and fish tissues from the shallow, slightly alkaline Lake Neusiedl were measured for their total mercury content with cold vapour atomic absorption spectroscopy (CV-AAS). Hg content of surface water was below the LOD of 0.1 mu g/L and the sediments displayed con...
Statistical-thermodynamic models for the description of ordering in non-stoichiometric intermetallic phases can be very helpful for the design of new functional materials for various purposes. Here, we present a review of methods for describing B2 (BCC) and L12 (FCC) – type binary alloys. The free energy of binary alloys where ordered structures ar...
Primary production in large areas of the open ocean is limited by low
iron concentrations. Rivers are potential sources of iron to the ocean,
however, riverine iron is prone to intense flocculation and
sedimentation in the estuarine mixing zone. Here we report the detection
of iron-rich nanoparticles in a typical peatland-draining creek which
are r...
Two enantiomerically pure thiosemicarbazone-proline conjugates with enhanced aqueous solubility, namely, 2-hydroxy-3-methyl-(S)-pyrrolidine-2-carboxylate-5-methylbenzaldehyde thiosemicarbazone [L-Pro-STSC or (S)-H(2)L] and 2-hydroxy-3-methyl-(R)-pyrrolidine-2-carboxylate-5-methylbenzaldehyde thiosemicarbazone [D-Pro-STSC or (R)-H(2)L] have been syn...
A generalized, quantitative, and predictive statistical-thermodynamic model is proposed employing a quasi-chemical argument for description of thermodynamic behavior and ordering phenomena in B2 ordered binary intermetallic materials. A modified procedure is given for the application of the Bethe-Guggenheim QC method which takes into account the pr...
Samples from a pristine raised peat bog runoff in Austria, the Tannermoor creek, were analysed for their iron linked to natural organic matter (NOM) content. Dissolved organic carbon
The coarse PVA-alginate matrix gel beads entrapping the micro-droplets of the ionic liquid tricaprylylmethylammonium 2-(methylthio) benzoate ([A336][MTBA]) as novel solid-phase extractants were prepared for the removal of mercury (II) from aqueous media. The ionic liquid [A336][MTBA] immobilized PVA-alginate beads (PVA/IL) have been characterized b...
In a fundamental study the potential of ionic liquids based on quaternary ammonium- and phosphonium cations and thiol-, thioether-, hydroxyl-, carboxylate- and thiocyanate-functionalized anions has been assessed for future application in advanced sewage treatment. The elimination of the metal(oid)s Ag, As, Cd, Cr, Cu, Hg, Ni, Pb, Pt, Sn, Zn and the...
Abstract Extraction of Zn(II) from aqueous solution using polymer inclusion membranes based on poly(vinyl chloride) containing the
phosphonium-based ionic liquid trihexyl(tetradecyl)phosphonium chloride (Cyphos® IL 101) is described. Zn(II) could efficiently be extracted from 5 M hydrochloric acid solution with membranes containing
30 wt% Cyphos IL...
The magnetic behavior of a binary salt of tricaprylylmethylammonium tetrachloroferrate and tricaprylylmethylammonium chloride, [A336][FeCl 4] 0.73[Cl] 0.27, was evaluated. With a magnetic susceptibility of 0.011 emu mol - 1 this binary salt exhibited a remarkable response to an external magnetic field. Dynamic light scattering (DLS) measurements al...
A statistical–thermodynamic model based on a defect correlation model (DCM) is proposed for the description of ordering phenomena and thermodynamic behavior in nano-crystalline thin-film materials with L12-structure, taking into account the presence of vacancies and anti-structure atoms in the structure. It includes a description of both long-range...
Iron(III) was efficiently extracted from a 6 M hydrochloride solution with the ionic liquid trihexyl(tetradecyl)phosphonium chloride, Cyphos (R), dissolved in chloroform. Spectroscopical data revealed that iron exists as tetrachloroferrate species in the organic phase. In contrast, nickel(II) was not extracted under experimental conditions. Satisfy...
Peat bogs have the ability to produce strong chelate ligands (humic and fulvic acids) which enhance the weathering rates of iron-silicate minerals and greatly increase the solubility of the essential trace metal iron in river water. Fluvial networks link peat bogs with the ocean, and thus terrestrial-derived fulvic-iron complexes fuel the ocean's b...
Methylation of N-phenyl-N′-(pyridin-2-ylmethyl)thiourea led to a new low melting thiouronium iodide salt, whereas a further methylation of the nitrogen of the pyridine ring was not successful. This could be explained by the inactivity of the nitrogen atom due to the sterical shielding revealed by crystallographic data. Exchange of the iodide anion...
Several hydrophobic long-chain quaternary ammonium and phosphonium ionic liquids (ILs) with functionalized aromatic anions were prepared following a metathesis route using tricaprylmethylammonium chloride (Aliquat 336) and trihexyl(tetradecyl)phosphonium chloride (Cyphos IL101) as precursors. The incorporation of aromatic anions bearing hydroxy-, m...
General geochemical parameters of water, superficial sediments, and suspended particulate matter (SPM) were determined from small shallow saline lakes (soda ponds) as well as from lake Neusiedlersee in eastern Austria. Additionally, instrumental neutron activation analysis (INAA) was used to determine the distribution of major, rare earth and other...
For determining natural levels of (236)U with its environmental abundance of 10(-16)% rather large sample volumes (approximately 30L) are necessary, therefore the conventional radiochemical uranium analysis (pre-concentration and column chromatography) is very time consuming. To speed up the procedure hydrophobic ionic liquids (ILs) were evaluated...
To date, little is known about the pH-stimulated mineralization of organic matter in aquatic environments. In this study, we investigated biodegradation processes in alkaline waters. Study site is a large shallow soda lake in Central Europe (Neusiedler See/Ferto). The decomposition rate of plant litter was measured as a function of pH by incubating...
Several hydrophobic ionic liquids (ILs) based on long-chain aliphatic ammonium- and phosphonium cations and selected aromatic anions were analyzed by reversed-phase high-performance liquid chromatography (RP-HPLC) employing trifluoroacetic acid as ion-pairing additive to the acetonitrile-containing mobile phase and adopting a step-gradient elution...
A generalized statistical-thermodynamic model for non-stoichiometric binary B2 phases was developed on the basis of a Bethe–Bragg–Williams approximation, with pair interaction energies as input parameters. The model considers both vacancies and anti-structure atoms as possible point defects on the two sublattices; it allows therefore a description...
New hydrophobic ionic liquids were synthesized from tricaprylmethylammonium chloride (Aliquat 336©) and selected Bronsted acids by a sustainable, simple and cost-saving deprotonation-metathesis route. Prepared ionic liquids were evaluated as potential extracting agents for cadmium from different aqueous solutions. High efficiency and selectivity we...
Tissue samples from 121 adult specimens of the predominantly herbivorous fish species nase, Chondrostoma nasus (L. 1758), from five river sites in Austria were analyzed for their metal content. Sediments and water samples of the sites show different levels of metal load, with only one site considered being polluted with metals. The concentrations o...
Ordering phenomena in bcc (110) binary thin film intermetallics are studied by a statistical–thermodynamic model. The system is modeled by an Ising approach that includes only nearest-neighbor chemical interactions and is solved in a mean-field approximation. Vacancies and anti-structure atoms are considered on both sublattices. The model describes...
The thermodynamic activity of antimony was determined for nickel–antimony alloys in the composition range between 20 and 52at% Sb by means of a Knudsen Effusion Mass Spectrometric (KEMS) method. The experimental data in the homogeneity range of the hexagonal γ-NiSb phase (B8-type) were compared with the literature data obtained by a different metho...
The influence of natural metal chelators on the bio-available iron input to the ocean by river water was studied. Ferrous and ferric ions present as suspended colloidal particles maintaining the semblance of a dissolved load are coagulated and settled as their freshwater carrier is mixed with seawater at the continental boundary. However, we might...
The influence of natural metal chelators on the bio-available iron input
to the ocean by river water was studied. Ferrous and ferric ions present
as suspended colloidal particles maintaining the semblance of a
dissolved load are coagulated and settled as their freshwater carrier is
mixed with seawater at the continental boundary. However, we might...
Dilute soda lakes are among the world's most productive environments and are usually dominated by dense blooms of cyanobacteria. Up to now, there has been little information available on heterotrophic bacterial abundance, production, and their controlling factors in these ecosystems. In the present study the main environmental factors responsible f...
Based on the Bragg-Williams approximation, a statistical-thermodynamic approach is presented for non-stoichiometric binary B2 phases with a pure anti-structure defect mechanism. Whereas in the original Bragg-Williams model only the state of long-range order is considered and no correlations are allowed in the arrangement of the point defects, short...
A statistical-thermodynamic model for binary nonstoichiometric intermetallic A3B compounds with D019-structure was developed based on a mean-field approximation. Vacancies and anti-structure atoms are allowed on the two sublattices as possible point defects. Due to the identical stoichiometry and the analogous coordination around A and B atoms it t...
A statistical-thermodynamic model for binary non-stoichiometric D03-phases has been developed based on a mean-field approximation. The corresponding D03 crystal lattice is divided into three sublattices, the α-, β- and γ-sublattices, where A-atoms occupy the α- and γ-sublattices, and B-atoms occupy the β-sublattice in the perfectly ordered case. Ne...
A new method for solving the Ising problem is presented, which can easily be applied to binary ordered intermetallic compounds. Calculation of the partition function by this method is possible not only for one-dimensional and two-dimensional lattices, but also for three-dimensional cases. Ordering of a three-dimensional lattice with NaCl structure...
There has been considerable interest in recent years in the properties of intermetallic compounds with the cubic L1â-structure. One prominent example is the compound NiâAl which has gained technological importance in the development of the so-called superalloys due to some of its unique properties like high temperature strength and excellent corros...
A statistical-thermodynamic model was derived which allows to describe thermodynamic activities in intermetallic compounds with L12-structure as a function of composition and temperature. The energies of formation of the four types of point defects (anti-structure atoms and vacancies on both sublattices) were used as adjustable parameters. The mode...
A statistical-thermodynamic model for binary nonstoichiometric L12-phases has been developed based on a mean-field approximation. Vacancies and anti-structure atoms are allowed on both sublattices as possible point defects, and the expressions for the defect concentrations as functions of composition and temperature have been derived. From these th...
A statistical thermodynamic model of ordering in nonstoichiometric B2-phases is developed, based on the oldest and simplest theory of ordering, the mean-field approximation with constant pair-wise interaction energies between nearest-neighbor atoms. This approximation is limited to the description of the distribution of atoms and vacancies on the d...
High-field 57Fe Mössbauer investigations up to 13.5 T on a series of FexAl1-x alloys around x=0.5 and magnetic measurements on a 51.8% sample are performed between 4.2 and 295 K. The experimental results are complemented with augmented spherical-wave (ASW) and linear augmented plane-wave (LAPW) band structure as well as thermodynamic model calculat...
Rh1+xTe2 powder samples (x=0.15, 0.28, 0.40, 0.51 and 0.84) were prepared using the isopiestic method to obtain well defined and crystallized samples. Rietveld structure refinements were carried out using the monoclinic I2/m space group, From the atomic position data and cell parameters variation versus composition, it was, concluded that the 0.15<...
Rh1+xTe2 powder samples (x=0.15, 0.28, 0.40, 0.52 and 0.84) were prepared using the isopiestic method to obtain well defined and crystallized samples. Rietveld structure refinements were carried out using the monoclinic I2/m space group. From the atomic position data and cell parameters variation versus composition, it was concluded that the 0.15<x...
Tellurium vapor pressures were determined by an isopiestic method for solid rhodium-tellurium alloys in the composition range between about 50 and 70 at.% Te and the temperature range between about 650 and 1100 °C. Activities and partial molar enthalpies of tellurium were derived from them. The results are interpreted in terms of a statistical-theo...
Simple statistical models of the Wagner-Schottky or the related Bragg-Williams type explain a number of phenomena which occur in non-stoichiometric ordered alloys. In particular, the activities of the alloy components as functions of the composition can be described with satisfactory accuracy. A new model of the Wagner-Schottky type is derived in t...
Tellurium vapor pressures were determined by an isopiestic method for solid titanium - tellurium alloys with NiAs-derivative crystal structures between 55 and 66.7 at.% Te and between 825 and 1350 K. Activities and partial molar enthalpies of tellurium were derived from them. The results are interpreted in terms of a statistical theoretical model,...
To gain insight to the nature of the order-disorder transformation in alloys, the Ising model with nearest-neighbour interactions is frequently used. The three-dimensional Ising model cannot be solved exactly, but modern approximation methods yield results which do not differ widely from exact solutions. Their mathematical derivations are complicat...
The transformation curve of V3Te4 (with a superstructure of the Cr3S4 type) into the corresponding high temperature phase (with a partially filled CdI2-type structure) is calculated using a statistical model derived in a previous paper. A long-range order parameter ν is defined and it is demonstrated that the ordered superstructure breaks down when...
Previous isopiestic measurements of tellurium vapour pressures over solid vanadium-tellurium alloys were re-evaluated in the light of new information on the vanadium-tellurium phase diagram. From these, partial molar properties of tellurium were derived for the V3Te4 phase. A statistical model was derived that describes the composition dependence o...
Manganese activities of the β′ RhMn phase were determined between 1150 and 1330 K and 48 and 57 at% Mn by an isopiestic method. The partial molar properties of manganese at 1273 K were derived. A statistical model for B2 phases was applied to interpret the thermodynamic properties, yielding a concentration of antistructure atoms a = b = 0.002 and a...
Arsenic vapor pressures were determined by an isopiestic method over liquid palladium-arsenic alloys (between 32 and 50 at.% As and between 900 and 1300 K) and over solid PdAs2 (between 750 and 1000 K). Activities and partial molar enthalpies of arsenic were derived, and integral thermodynamic properties for liquid alloys were obtained by Gibbs-Duh...
A generalized statistical model is developed which describes the composition dependence of the thermodynamic properties of intermetallic B2-phases. The model can be applied to both types of defect mechanisms found in this structure type, i.e. anti-structure and triple-defects; in addition it can describe any hybrid behavior where both types of defe...
Zinc vapor pressures of liquid and solid gold-zinc alloys were determined by an isopiestic method. The principles of this method are outlined and possible errors are analyzed. The application of the nonisothermal isopiestic method at very low vapor pressures and the possibly necessary corrections are discussed. Activities and partial molar enthalpi...
Zinc vapor pressures over liquid and solid gold-zinc alloys were determined by an isopiestic method between about 750 and 1350 K and between 18 and 70 at.% Zn. Activities and partial molar enthalpies of zinc were derived, and integral thermodynamic properties for liquid alloys were obtained by Gibbs-Duhem integration. A statistical model for B2 pha...
Manganese activities of the beta -PtMn phase were determined between 1100 and 1400 K and 45 and 65 at. % Mn by an isopiestic technique. The partial molar properties of manganese at 1273 K were derived. A statistical model for L1//0 phases was applied to interpret the thermodynamic properties yielding a disorder parameter alpha equals 2 multiplied b...
A statistical model is developed that describes the composition dependence of the thermodynamic activities in phases with the NiAs-(B8-) structure. The model is based on vacancies in the transition metal sublattice (octahedral sites) and additional transition metal atoms in interstitial positions (trigonal-bipyramidal sites) as intrinsic disorder....
Die Mn-Aktivitäten der Titelphase (geordnete BZ-Struktur) werden im Temp.-Bereich l 125-1350 K und 48-58 Atom-% Mn mit Hilfe einer isopiestischen Methode bestimmt und die partiellen molaren Größen von Mn bei I273 K abgeleitet.
Thermodynamische Mn-Aktivit?ten wurden mit einer speziell adaptierten isopiestischen Methode in der ??-AuMn-Phase mit geordneter B2-Struktur bestimmt, und zwar zwischen 1100 und 1400 K und zwischen 40 und 60 At-% Mn.
An einer Reihe von Legierungen mit CsCl-Struktur im Zusammensetzungsbereich 37-56 Atom-% Mn wird das magnetische Verhalten der Titelphase untersucht.
Manganese activities of beta prime -AuMn phase with the ordered B2-structure were determined between 1100 and 1400 K and between 40 and 60 at. % Mn by a specially adapted isopiestic method. The partial molar properties of manganese at 1273 K were derived. With a calorimetrically determined value of DELTA H equals minus 23. 3 kJ g-atom** minus **1 f...