Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Iron
Type of Medium
Language
Year
  • 1
    In: Soil Science Society of America Journal, March-April, 2002, Vol.66(2), p.437(8)
    Description: The Fe-cyanide complexes ferricyanide, [[Fe[(CN).sub.6]].sup.3-], and ferrocyanide, [[Fe[(CN).sub.6]].sup.4-], are of an anthropogenic source in soils. As the complexes are largely charged, sorption on the soil matrix is a possible retention mechanism for these anions. To evaluate soil properties controlling Fe-cyanide complex sorption, experiments were performed with 17 uncontaminated soil horizons by a batch technique. Soil organic matter (SOM) was destroyed in six horizons. The experiments were conducted at soil pH, reaction time of 24 h, and an ionic strength of 0.01 (NaN[O.sub.3]). The affinity of the Fe-cyanide complexes for the soil matrix differed, because 14 samples sorbed higher amounts of ferrocyanide than of ferricyanide. Calculated sorption maxima were quantitatively explained by physical and chemical soil properties using multiple regressions. The regression equations were checked by variance analysis. The regression equations for all samples showed that the sorption of both complexes depended on organic C ([C.sub.org]), clay, and oxalate-extractable Fe ([Fe.sub.o]). The sorption of the complexes on soils containing 〈10 g [C.sub.org] [kg.sup.-1] was governed by pH and clay contents. Clay and oxalate-extractable Al ([Al.sub.o]) were the most important properties influencing ferricyanide sorption on samples containing high amounts of [C.sub.org]. On the same samples, ferrocyanide sorption was governed by [Al.sub.o]. Organic matter promotes the sorption of both complexes, especially on Fluvisol samples. Destruction of SOM of these samples minimized the sorption by up to 99%. Therefore organic matter in these soils may have a special affinity for Fe-cyanide complexes possibly because of the reaction between Fe-cyanide N and reactive groups of SOM.
    Keywords: Soil Science -- Research ; Cyanides -- Research
    ISSN: 0361-5995
    E-ISSN: 14350661
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: Environmental pollution, 2011, Vol.159(5), pp.1398-1405
    Description: Arsenic mobility may increase in liquid phase due to association with colloidal Fe oxides. We studied the association of As with Fe oxide colloids in the effluent from water-saturated soil columns run under anoxic conditions. Upon exfiltration, the solutions, which contained Fe²⁺, were re-aerated and ferrihydrite colloids precipitated. The entire amount of effluent As was associated with the ferrihydrite colloids, although PO₄ ³⁻, SiO₄ ⁴⁻, CO₃ ²⁻ and dissolved organic matter were present in the effluent during ferrihydrite colloid formation. Furthermore, no subsequent release of As from the ferrihydrite colloids was observed despite the presence of these (in)organic species known to compete with As for adsorption on Fe oxides. Arsenic was bound via inner-sphere complexation on the ferrihydrite surface. FTIR spectroscopy also revealed adsorption of PO₄ ³⁻ and polymerized silica. However, these species could not impede the quantitative association of As with colloidal ferrihydrite in the soil effluents. ; p. 1398-1405.
    Keywords: Iron Oxides ; Dissolved Organic Matter ; Effluents ; Arsenic ; Adsorption ; Polymerization ; Anaerobic Conditions ; Ferrihydrite ; Iron ; Colloids ; Silica ; Fourier Transform Infrared Spectroscopy ; Soil
    ISSN: 0269-7491
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Environmental Pollution, 2011, Vol.159(5), pp.1398-1405
    Description: Arsenic mobility may increase in liquid phase due to association with colloidal Fe oxides. We studied the association of As with Fe oxide colloids in the effluent from water-saturated soil columns run under anoxic conditions. Upon exfiltration, the solutions, which contained Fe , were re-aerated and ferrihydrite colloids precipitated. The entire amount of effluent As was associated with the ferrihydrite colloids, although PO , SiO , CO and dissolved organic matter were present in the effluent during ferrihydrite colloid formation. Furthermore, no subsequent release of As from the ferrihydrite colloids was observed despite the presence of these (in)organic species known to compete with As for adsorption on Fe oxides. Arsenic was bound via inner-sphere complexation on the ferrihydrite surface. FTIR spectroscopy also revealed adsorption of PO and polymerized silica. However, these species could not impede the quantitative association of As with colloidal ferrihydrite in the soil effluents. ► Ferrihydrite (Fh) colloids precipitated from a solution derived from soil. ► Arsenic that was discharged from soil entirely associated with these colloids. ► Arsenic was strongly bound to the Fh surface via inner-sphere complexation. ► A complexation of As by organic species discharged from soil was not detected. ► (In)organic solutes in the solution from soil could not impede the As–Fh association. Natural concentrations of competing (in)organic species in soil-derived solutions do not impede the strong and quantitative association between As and colloidal ferrihydrite.
    Keywords: Iron Hydroxide ; Phosphate ; Silicate ; Carbonate ; Dissolved Organic Matter ; Engineering ; Environmental Sciences ; Anatomy & Physiology
    ISSN: 0269-7491
    E-ISSN: 1873-6424
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: Chemosphere, May 2016, Vol.150, pp.390-397
    Description: Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX) combined with a seven steps sequential extraction technique were used to assess the geochemical distribution of chromium (Cr) and lead (Pb) in a contaminated floodplain soil. Total contents of Cr and Pb were 490.3 and 402.1 mg kg , respectively. The residual fraction was 59.5 and 56.3% of total Cr and Pb. The crystalline iron (Fe) oxide was the dominant non-residual fraction of Cr (35.9% of total Cr). Considerable amounts of Pb were found in the organic fraction (35.4%). Using C nuclear magnetic resonance spectroscopy, the soil organic matter was identified as 48.9% aromatic carbon, which indicated that a certain portion of Pb and Cr might be associated with aromatic compounds. The SEM–EDX images demonstrate a concomitant occurrence of Pb, manganese (Mn), Fe, and aluminum (Al) as well as a coexistence of Cr and Fe. The release dynamics of dissolved Cr and Pb as affected by redox potential (E ), pH, Fe, Mn, dissolved organic carbon, and sulfate was quantified using an automated biogeochemical microcosm apparatus. Soil pH decreased under oxic conditions. The release of Cr, Pb, Fe, and Mn increased under acidic oxic (pH = 3.7, E  = 521 mV) conditions due to the associated decrease of pH (7.1–3.7). The mobilization of Cr and Pb was affected by the Fe and Mn. In conclusion, our multi-technique approach identified the geochemical distribution of Cr and Pb and verified major factors that explain mobilization of Cr and Pb in floodplain soils.
    Keywords: Toxic Metals ; Mobilization ; Wetlands ; Scanning Electron Microscope Coupled With Energy Dispersive X-Ray Analysis (SEM–Edx) ; Nuclear Magnetic Resonance Spectroscopy (NMR) ; Chemistry ; Ecology
    ISSN: 0045-6535
    E-ISSN: 1879-1298
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: English
    In: Geochimica et cosmochimica acta, 2012, Vol.77, pp.444-456
    Description: Recent studies on the microbial reduction of synthetic iron oxide colloids showed their superior electron accepting property in comparison to bulk iron oxides. However, natural colloidal iron oxides differ in composition from their synthetic counterparts. Besides a potential effect of colloid size, microbial iron reduction may be accelerated by electron-shuttling dissolved organic matter (DOM) as well as slowed down by inhibitors such as arsenic. We examined the microbial reduction of OM- and arsenic-containing ferrihydrite colloids. Four effluent fractions were collected from a soil column experiment run under water-saturated conditions. Ferrihydrite colloids precipitated from the soil effluent and exhibited stable hydrodynamic diameters ranging from 281 (±146)nm in the effluent fraction that was collected first and 100 (±43)nm in a subsequently obtained effluent fraction. Aliquots of these oxic effluent fractions were added to anoxic low salt medium containing diluted suspensions of Geobacter sulfurreducens. Independent of the initial colloid size, the soil effluent ferrihydrite colloids were quickly and completely reduced. The rates of Fe²⁺ formation ranged between 1.9 and 3.3fmolh⁻¹cell⁻¹, and are in the range of or slightly exceeding previously reported rates of synthetic ferrihydrite colloids (1.3fmolh⁻¹cell⁻¹), but greatly exceeding previously known rates of macroaggregate-ferrihydrite reduction (0.07fmolh⁻¹cell⁻¹). The inhibition of microbial Fe(III) reduction by arsenic is unlikely or overridden by the concurrent enhancement induced by soil effluent DOM. These organic species may have increased the already high intrinsic reducibility of colloidal ferrihydrite owing to quinone-mediated electron shuttling. Additionally, OM, which is structurally associated with the soil effluent ferrihydrite colloids, may also contribute to the higher reactivity due to increasing solubility and specific surface area of ferrihydrite. In conclusion, ferrihydrite colloids from soil effluents can be considered as highly reactive electron acceptors in anoxic environments. ; p. 444-456.
    Keywords: Colloids ; Iron Oxides ; Dissolved Organic Matter ; Effluents ; Arsenic ; Hydrodynamics ; Solubility ; Ferrihydrite ; Geobacter Sulfurreducens ; Iron ; Surface Area ; Soil
    ISSN: 0016-7037
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: Environmental Geochemistry and Health, 2017, Vol.39(6), pp.1291-1304
    Description: European floodplain soils are frequently contaminated with potentially toxic inorganic substances. We used a multi-surface model to estimate the aqueous concentrations of Cd, Cu, Ni, Pb and Zn in three Mollic Fluvisols from the Central Elbe River (Germany). The model considered complexation in solution and interactions with soil organic matter (SOM), a clay mineral and hydrous Al, Fe and Mn oxides. The amounts of reactive metals were derived from extraction with 0.43 M HNO 3 . Modelling was carried out as a function of pH (soil pH ± 1.4) because it varies in floodplain soils owing to redox processes that consume or release protons. The fraction of reactive metals, which were dissolved according to the modelling, was predominantly 〈1%. Depending on soil properties, especially pH and contents of SOM and minerals of the clay fraction, the modelled concentrations partially exceeded the trigger values for the soil–groundwater pathway of the German soil legislation. This differentiation by soil properties was given for Ni, Pb and Zn. On the other hand, Cd was more mobile, i.e., the trigger values were mostly exceeded. Copper represented the opposite, as the modelling did not predict exceeding the trigger values in any horizon. Except for Pb and partially Zn (where oxides were more important), SOM was the most important adsorbent for metals. However, given the special composition and dynamics of SOM in mollic horizons, we suggest further quantitative and qualitative investigations on SOM and on its interaction with metals to improve the prediction of contaminant dynamics.
    Keywords: Floodplain soil ; Metals ; Soil contamination ; Adsorption ; Multi-surface modelling
    ISSN: 0269-4042
    E-ISSN: 1573-2983
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: Water Research, 2002, Vol.36(19), pp.4877-4883
    Description: Blast furnace sludge is a waste originating from pig iron production and contains small amounts of iron-cyanide complexes. Leaching of iron-cyanide complexes from deposited blast furnace sludge into the ground water seems to be possible in principle. We investigated the sorption of the iron-cyanide complexes ferrocyanide, [Fe super(II)(CN) sub(6)] super(4-), and ferricyanide, [Fe super(III)(CN) sub(6)] super(3-), in 22 samples of deposited blast furnace sludge in batch experiments. Subsequently, desorption of iron-cyanide complexes was investigated using 1 M NaCl. Sorption in five samples was evaluated with Langmuir isotherms. The blast furnace sludge samples were neutral to slightly alkaline (pH 7.6-9) and consisted of X-ray amorphous compounds and crystalline Fe oxides primarily. X-ray amorphous compounds are assumed to comprise coke-bound C and amorphous Fe, Zn, and Al oxides. The experiments that were evaluated with Langmuir isotherms indicated that the extent of ferricyanide sorption was higher than that of ferrocyanide sorption. Saturation of blast furnace sludge with iron-cyanide complexes was achieved. Sorption of iron-cyanide complexes in 22 blast furnace sludge samples at one initial concentration showed that 12 samples sorbed more ferrocyanide than ferricyanide. The extent of sorption largely differed between 0.07 and 2.76 mu mol [Fe(CN) sub(6)]m super(-2) and was governed by coke-bound C. Ferricyanide sorption was negatively influenced by crystalline Fe oxides additionally. Only small amounts of iron-cyanide complexes sorbed in blast furnace sludge were desorbed by 1 M NaCl (ferrocyanide, 3.2%; ferricyanide, 1.1%, given as median). This indicated strong interactions of iron-cyanide complexes in blast furnace sludge. The mobility of iron-cyanide complexes in deposited blast furnace sludge and consequently contamination of the seepage and ground water was designated as low, because (i) deposited blast furnace sludge is able to sorb iron-cyanide complexes strongly, (ii) the solubility of the iron-cyanide-containing phase, K sub(2)Zn sub(3)[Fe super(II)(CN) sub(6)] times 9H sub(2)O, is known to be low, and (iii) a worst case scenario of the transport of iron-cyanide complexes within the blast furnace sludge deposit indicated strong retardation of the complexes within the next 100 years.
    Keywords: Iron–Cyanide Complexes ; Sorption ; Desorption ; Blast Furnace Sludge ; Engineering
    ISSN: 0043-1354
    E-ISSN: 1879-2448
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: Geoderma, February 2013, Vol.193-194, pp.117-121
    Description: The synthesis of pure birnessite (δ-MnO ) by a simple, fast and reliable method is introduced. Birnessite was synthesized by a sol–gel reaction involving the reduction of KMnO by lactate at ambient pressure and temperature. Our method does not include the use of strong acids and bases and does not produce toxic residues. The results from both X-ray diffraction and Fourier-transform infrared spectroscopy, compared with a synthesized reference material, verified our synthesized mineral as birnessite. Secondary electron images showed a micro-porous structure of aggregated birnessite colloids, and consistently, we measured a very large specific BET surface area of 249.15 ± 0.05 m g . Birnessite is known to have a variable mineral formula, and the elemental composition of our mineral is within the range of other birnessites. Birnessite obtained by this procedure could serve as a model mineral for laboratory experiments on the biogeochemistry of Mn, and furthermore it may also have a potential as electron acceptor for remediation purposes. ► Pure birnessite was synthesized by a simple, fast, reliable and inexpensive method. ► This birnessite can serve as a model mineral in studies on the biogeochemistry of Mn. ► It may have potential for the remediation of contaminated soils.
    Keywords: Ftir ; Xrd ; Specific Surface Area ; Manganese Oxide ; Remediation ; Sol–Gel Synthesis ; Agriculture
    ISSN: 0016-7061
    E-ISSN: 1872-6259
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Language: English
    In: Journal of Plant Nutrition and Soil Science, August 2013, Vol.176(4), pp.497-499
    Description: Avoiding chemical and physical artifacts during sampling is crucial for realistic analyses of mineral and other colloids in soil. We developed a sampler, which allows for the collection of Fe oxides that precipitate in their natural environment in a Bg horizon of a Calcaric Gleysol. Simultaneous measurements of redox‐sensitive parameters confirmed temporal changes from Fe‐reducing to Fe‐oxidizing conditions on site.
    Keywords: Sampling ; Fe Oxides ; Redoximorphic Soil ; Gleysol
    ISSN: 1436-8730
    E-ISSN: 1522-2624
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Language: English
    In: Chemical geology, 2012, Vol.332, pp.116-123
    Description: Geogenic CO₂, which ascends on so-called mofette sites, may affect development and properties of soils. Therefore, we studied soils on a mofette site in the Czech Republic at three spots differing in the partial pressures of soil CO₂ (p(CO₂)=0.04, 1, and 1). We recorded 69 Fe K-XANES spectra in 5 regions of interest on 3 thin sections in fluorescence mode. Iron was enriched in filled pores, e.g., former root channels. Generally, most of the Fe was identified in different clay minerals (smectites, illites and chlorites). Minor pedogenic Fe contributors were ferrihydrite, green rust, magnetite, maghemite, vivianite and siderite, whereas typical soil Fe (hydr)oxides such as goethite, hematite or lepidocrocite were never doubtlessly identified. The Fe(II)-containing minerals were particularly detected at p(CO₂)=1 indicating an effect of soil CO₂ on the formation of secondary Fe phases. Organic Fe complexes were less important, and their formation seemed to be inhibited at p(CO₂)=1. We thus conclude that geogenic CO₂ affects pedogenesis and causes quantitative and qualitative variations of Fe speciation. ; p. 116-123.
    Keywords: Goethite ; Chlorites ; Ferrihydrite ; Iron ; Carbon Dioxide ; Clay Minerals ; Absorption ; Siderite ; Fluorescence ; Hematite ; Root Channels ; Lepidocrocite ; Soil Formation ; Spectroscopy ; Maghemite ; X-Radiation ; Magnetite
    ISSN: 0009-2541
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages