Valence State Of Iron Research Articles

Determination of the Self-organized Mesoporous Materials Sorption Capacity in Water Treatment Processes Using Mössbauer Spectroscopy

Different approaches to water purification are considered. It is shown that for developing of effective purification methods in the different water treatment technologies special knowledge is necessary. This knowledge deals with physical-chemical processes of used reagents interaction with contaminating impurities. The obtaining of the necessary data on physics-chemical processes such as the formation of chemical compounds of iron, the change in valence state of iron, adsorption and absorption pollutants are analyzed. The usage of iron compounds as a cleaners and the water treatment from the iron pollutant are the events, in which Mössbauer spectroscopy allows to determine not only the chemical changes, but also to obtain quantitative data on the reaction products and on the sizes of reaction products and their quantities.

A Turn-Off Fluorescent Nanosensor for Iron in Aqueous Solution Based on Fluorescent Carbon Nanoparticles

The water-soluble fluorescent carbon nanomaterials with low toxicity and high biocompatibility are considered as promising materials for biomedical and sensor applications. Here, we report that a nanosensor system has been developed to simultaneously detect two valence states of iron ( Fe 2+ and/or Fe 3+) in aqueous solution based on fluorescent carbon nanoparticles (FCNs). The nanosensor has high selectivity and sensitivity with a limit of detection (LOD) of 5 μM, which is equivalent to 0.3 mg/L (5.36 μM) of iron in drinking water by United States Environment Protection Agency (US-EPA). Furthermore, a distinguishable color change of solution, from pale yellow to red-brown, can be observed as iron concentration reaching 40 μM, which provides way for fast, visible detection of irons.

Low Mantle Perovskite: Solid Solution, Spin State of Iron and Water Solubility

Silicate perovskites ((Mg, Fe)SiO3 and CaSiO3) are believed to be the major constituent minerals in the lower mantle. The phase relation, solid solution, spin state of iron and water solubility related to the lower mantle perovskite are of great effect on the geodynamics of the Earth's interior and on ore mineralization. Previous studies indicate that a large amount of iron coupled with aluminum can incorporate into magnesium perovskite, but this is discordant with the disproportionation of (Mg,Fe)SiO3 perovskite into iron-free MgSiO3 perovskite and hexagonal phase (Mg0.6Fe0.4)SiO3 in the Earth's lower mantle. MnSiO3 is the first chemical component confirmed to form wide range solid solution with CaSiO3 perovskite and complete solid solution with MgSiO3 perovskite at the P-T conditions in the lower mantle, and addition of MnSiO3 will strongly affects the mutual solubility between MgSiO3 and CaSiO3. The spin state of iron is deeply depends on the site occupation of the Fe3+ or Fe2+, the synthesis and the annealing conditions of the sample. It seems that the spin state of Fe2+ in the lower mantle perovskite can be settled as high spin, however, the existence of intermediate spin or low spin state of Fe2+ in perovskite has not been clarified. Moreover, different results have also been reported for the spin state of Fe3+ in perovskite. The water solubility of the lower mantle perovskite is related with its composition. In pure MgSiO3 perovskite, only less than 500 ppm water was reported. Al–MgSiO3 perovskite or Al–Fe–MgSiO3 perovskite in the lower mantle accommodates water of 1100 to 1800 ppm. Further experiments are necessary to clarify the detailed conditions for perovskite solid solution, to reliably analyze the valence and spin states of iron in the coexisting iron-bearing phases, and to compare the water solubility of different phases at different layers for deeply understanding the geodynamics of the Earth's interior and ore mineralization.

Mössbauer study of the effect of pH on Fe valence in iron–polygalacturonate as a medicine for human anaemia

Abstract Iron–polygalacturonate complexes have been synthesized from polygalacturonic acid by applying a novel preparation method in order to develop medicine suitable for the effective iron supplementation of the human body in the case of anemia. Since the iron uptake depends on the oxidation state of iron, 57Fe Mossbauer spectroscopy was used to study the occurrence of different valence states in the iron–polygalacturonate complexes prepared under different circumstances. The Mossbauer-spectra indicated the presence of iron both in FeII and FeIII states in the investigated iron–polygalacturonate compounds, the occurrence of which varied with the preparation parameters. A correlation of the relative occurrence of iron valence states with the pH has been found. The relative occurrence of FeIII was found to increase with increasing pH. The knowledge of this correlation can help find optimum preparation conditions of iron–polygalacturonates to cure human anemia.

Local order and valence state of Fe in urban suspended particulate matter

X-ray absorption spectroscopy investigations were carried out on urban suspended particulate matter (PM2.5) with the aim of studying the local order and valence state of iron, a metal abundant in this type of material, particularly in urban environments. XANES results, based on the comparison with model compounds fayalite (Fe2+) and ferrihydrite (Fe3+), show that iron is prevalent as Fe3+, whereas EXAFS data attribute the prevalent Fe3+ to a nanocrystalline phase of ferrihydrite. The dominance of Fe3+ (less soluble than Fe2+) is further confirmed by the fact that previous leaching experiments did not show Fe presence in the solution.

Magnetic and transport properties of Ca1.5La0.5FeMo1−xWxO6 perovskites

The Ca1.5La0.5FeMo1−xWxO6 double perovskites with x⩽0.3 crystallize in a monoclinic structure having space group P21/n. The degree of crystallographic ordering is increased as the tungsten content is higher. As a result, there is an increase of both saturation magnetizations and Curie temperatures. The magnetic susceptibilities follow temperature dependences typical for a ferrimagnetic system. The valence states of iron and molybdenum ions as well their distributions in the lattice sites were determined. These data were correlated with magnetic and transport properties.

Investigating Surface and Interface Phenomena in LiFeBO3 Electrodes Using Photoelectron Spectroscopy Depth Profiling

The formation of surface and interface layers at the electrodes is highly important for the performance and stability of lithium ion batteries. To unravel the surface composition of electrode materials, photoelectron spectroscopy (PES) is highly suitable as it probes chemical surface and interface properties with high surface sensitivity. Additionally, by using synchrotron-generated hard x-rays as excitation source, larger probing depths compared to in-house PES can be achieved. Therefore, the combination of in-house soft x-ray photoelectron spectroscopy and hard x-ray photoelectron spectroscopy (HAXPES) enables reliable and non-destructive depth profiling. Thus, detailed investigation of compositional gradients at electrode surfaces and interfaces from a sub-monolayer to several nanometer length scales can be performed. As this depth region is especially relevant for both electronic and ionic transport processes, the presented combinatorial approach is a very valuable tool in characterizing battery electrodes and their interfaces. We apply this technique to lithium iron borate (LiFeBO3) battery electrodes at different cycling conditions to study the surface and interface layer evolution. Due to its high theoretical capacity (220 mA h g-1) LiFeBO3 is a promising cathode material for lithium ion batteries. However, its application is limited because of significant degradation due to surface reactions upon exposure to moisture and air. Therefore, detailed compositional characterization of LiFeBO3 electrode surfaces is essential to gain further understanding of the degradation processes. To study these properties for the pristine material, the electrode fabrication conditions were carefully controlled to limit contact to air and moisture. The investigation of the iron valence state in dependence of the electrode preparation as well as cycling conditions is presented as higher valence states of iron are most likely involved in the degradation process.

Mössbauer spectroscopy analysis of valence state of iron in historical documents obtained from the National Library of South Africa

Abstract Documents of historical and cultural value are under constant risk of deterioration by acid hydrolysis and catalytic oxidation. The assessment of this risk of degradation is necessary in order to prepare for the conservation and preservation of such documents. The risk of oxidative degradation of four historical documents obtained from the National Library of South Africa and one sample from the Timbuktu manuscripts was assessed by determining the valence states of Fe in the samples using Mossbauer Spectroscopy (MS). The pH levels of the samples were also determined using the Abbey pH pen. It was found that all the samples were acidic, indicating that acid hydrolysis is occurring in all samples. One sample (Wildsport of Africa) had both Fe 2+ (21%) and Fe 3+ (79%); all the other samples had only Fe 3+ . The detection Fe 2+ in the Wildsport of Africa sample shows that oxidative degradation is also occurring in this document. The results also show for the first time ever that MS can be used to determine the valence state of trace amount of iron in paper.

Iron Cyanides As a Cathode Material for Lithium-Ion Batteries

Lithium ion battery is one of the most popular power sources for clean and efficient electrochemical energy storage and conversion. There are increasing interests for both the cathode and anode, in accordance with the development of portable electronic equipments, and automotive industry. As one of the potential alternatives, organic cathode1has advantages of low cost, environmentally friendly, easy fabrication compared to the inorganic cathodes. However, the low voltage plateau and poor cycle performance restrict its applications. Iron cyanide and its analogs2 have been pursued as attractive materials for fundamental research and large scale industrial applications since its electrochemical activity was first reported in 1978. These zeolite-like compounds have perfectly 3D polymeric frameworks due to the asymmetric CºN anion. Its large open spaces can not only accommodate transition metal ions but also some small molecules. Redox reaction can also take place there thanks to the iron valence state for charge balance. These characteristics exactly offer the tunnels and spaces for the transport and storage of lithium ions.Fe4[Fe(CN)6]33 is the foretype of prussian blue, its theoretical specific capacity is about 100 mAh/g with one charge transport of Fe2+/Fe3+. Here we synthesize this compound by a simple one-step precipitation method. The cell shows an initial specific capacity of 95.1 mAh/g and about 75% of its original capacity is retained after 50 cycles. In order to increase the specific capacity, Fe2+ was replaced with Fe3+ to provide more redox active sites. The as-prepared FeFe(CN)6 has a regular cubic structure with the particle size of 50 nm. Two redox peaks at 2.88V/3.19V and 3.81V/3.91V are observed by cyclic voltammetry, corresponding to the oxidation/reduction of the low spin Fe2+/Fe3+ adjacent to the carbon and the high-spin of Fe2+/Fe3+bonding to the nitrogen, respectively. Galvanostatic charge/discharge cycling shows that its initial discharge capacity is 137.3 mAh/g, and the capacity retention is 60% after 100 cycles. In addition, its rate performance is very excellent.1. Y. Liang, Z. Tao and J. Chen, Advanced Energy Materials, 2012, 742-769.2. A. A. Karyakin, Electroanalysis, 2001, 13, 813-819.3. N. Imanishi, T. Morikawa, J. Kondo, R. Yamane, Y. Takeda, O. Yamamoto, H. Sakaebe and M. Tabuchi, J Power Sources, 1999, 81, 530-534.

Phase Transformation in Laser‐Induced Micro‐Explosion in Olivine (Fe,Mg)2SiO4

We show that micro‐explosions generated by tightly focused single pulses of a femtosecond laser in olivine have produced change of iron valence state. Chemical and structural changes were investigated using synchrotron X‐ray spectroscopy, and Raman scattering. Near edge X‐ray absorption fine structure (NEXAFS) spectra from laser‐affected zone of olivine crystal indicate a modified chemical bonding and a possible formation of regions containing a new crystalline phases of iron. Raman scattering from the laser‐affected zone regions reveals loss of crystalline order and formation of a mixture of nano‐crystallites due to melting and re‐solidification of olivine. These results indicate that spatial separation between ions of different mass occurs in hot, highly excited olivine. The present study confirms that this mechanism may present a general pathway toward creation of novel crystalline and amorphous nano‐materials using fs laser‐induced confined micro‐explosions.

Spin and valence states of iron in Al-bearing silicate glass at high pressures studied by synchrotron Mossbauer and X-ray emission spectroscopy

High-pressure synchrotron Mossbauer (SMS) and X-ray emission (XES) spectroscopic measurements were conducted to investigate the spin and valence states of iron in (A1,Fe)-bearing magnesium silicate glass (Mg0.79Fe0.10Al0.10Si0.96O3) up to 126 GPa and 300 K. By analyzing the Fe K beta emission spectra using the integrated relative difference (IRD) method, which accounts for the spectral broadening effects, the derived total spin momentum (S) of the iron in the glass shows no observable changes with pressure within the experimental uncertainties. A two-doublet fitting model representing two diverse local iron atomic environments was used to satisfactorily simulate the high-pressure SMS spectra of iron in the glass. The doublet with an averaged quadrupole splitting (QS) value of 1.94(+/- 0.25) mm/s and chemical shift (CS) of 1.02(+/- 0.25) minis at ambient conditions was assigned to be high-spin Fe2+, whereas the second doublet with QS = 0.83(+/- 0.25) mm/s and CS = 0.49(+/- 0.25) mm/s was assigned to be high-spin Fe3+. Increasing pressure continuously elevates the QS of Fe2+ from similar to 2 mm/s at ambient pressure to 3.5 mm/s at 126 GPa, while Fe3+ only exhibits a slight increase in the QS to 1.34(+/- 0.25) mm/s. Comparing with previous experimental and theoretical studies on the local geometries and hyperfine parameters of silicate glasses and minerals, we conclude that the occurrence of the extremely high QS of Fe2+ in our glass above similar to 40-50 GPa can be associated with the enhanced density and diverse distortions and geometries of the local Fe2+ environments. Our combined XES and SMS results show that both Fe2+ and Fe3+ ions in Al-bearing silicate remain in the high-spin state, rather than undergoing a spin-pairing transition as proposed previously. Assuming that the silicate glass results can be used as an analog for understanding silicate melts, our results here indicate that iron ions likely experience significant changes in the local environments yet remain overall in the high-spin state in silicate melts at the extreme pressure and temperature conditions of the deep mantle.

Synthesis of ZnFe2O4 nanoparticles and their asymmetric configuration with Ni(OH)2 for a pseudocapacitor

Nanosized zinc ferrite (ZnFe2O4) particles are prepared by a simple aspartic acid assisted combustion method at three different pH conditions. X-ray diffraction analysis (XRD) is used to identify the single phase formation of ZnFe2O4 and its crystal system. The particle size and shape are revealed through transmission electron microscopy (TEM) images and the particles are in the size range between 20–30 nm. The valence states of zinc, iron and oxygen are determined through X-ray photoelectron spectroscopy (XPS). The electrochemical performances of the individual electrodes and fabricated cells are studied using cyclic voltammetry (CV), galvanostatic charge–discharge analysis (GCD) and impedance spectroscopy (EIS) analysis. A maximum specific capacitance of 1235 F g−1 at 1 mA cm−2 is obtained for ZnFe2O4 prepared at pH 10. Furthermore an asymmetric supercapacitor (ASC) is fabricated using ZnFe2O4 as the negative electrode and Ni(OH)2 as the positive electrode. Interestingly, this assembled ASC delivers good energy and power densities of 33 W h kg−1 and 68 W kg−1, respectively.

Synthesis, structure and valence-trapping vs. detrapping for new trinuclear iron pentafluoro benzoate complexes: possible recognition of organic molecules by 57Fe Mössbauer spectroscopy

New mixed-valence trinuclear iron pentafluorobenzoate complexes were synthesized. Their valence-detrapping and/or valence-trapping phenomena were studied by (57)Fe Mössbauer spectroscopy and X-ray crystallography. For [Fe3O(C6F5CO2)6(py)3]·CH2Cl2 (1), a valence-trapped state was observed at low temperatures, while the valence-detrapped state was observed at room temperature. Removal of CH2Cl2 from 1 gives the de-solvated [Fe3O(C6F5CO2)6(py)3] (2) where the valence was trapped at room temperature. The CH2Cl2-free 2 can reversibly absorb and desorb CH3CN; the process was followed by (57)Fe Mössbauer spectroscopy by monitoring valence-trapping and valence-detrapping phenomena. Organic molecules such as benzene, toluene, ethylbenzene, cumene, and xylene are also trapped by 2 and affect the iron valence states. However, small molecules such as H2O and CO2 do not affect the valence-trapped state of 2. Three xylene isomers trapped within the nano-void of 2 were distinguished by (57)Fe Mössbauer spectroscopy at room temperature.

Iron valence state of fine-grained material from the Jupiter family comet 81P/Wild 2 – A coordinated TEM/STEM EDS/STXM study

The oxidation state of transition metal elements is an indicator of the environmental conditions during formation and history of extraterrestrial materials. We studied the iron valence state of fine-grained material from a bulbous track extracted from the Stardust cometary collector. It likely originated from primitive material of the comet Wild 2. We used synchrotron-based Scanning Transmission X-ray Microscopy (STXM) to collect Fe L3-XANES spectra at a spatial resolution of about 20nm. Maps of Fe valence state were combined with the elemental maps recorded by energy dispersive X-ray spectroscopy (EDS) with a transmission electron microscope (TEM), on the same areas and with a comparable electron probe size (5–20nm). As for most Stardust fine-grained material, the samples are severely damaged by the hypervelocity impact in the aerogel collector blocks. They show of a wide range of oxidation state at a micrometer scale, from Fe metal to Fe3+. This heterogeneity of oxidation state can be due to the extreme conditions of the collection. Two major parameters can favor changes in redox state. The first is the high temperature regime, known to be highly heterogeneous and to have locally reached extreme values (up to 2000K). The second is the local chemical environment. It may contain elements that could favor a reduction or oxidation reaction within the flash-heated Wild 2 fragments. Comparison of maps by STXM and EDS shows evidence for several correlation trends between element concentrations and the iron valence state. These observations, together with the study of a melted rim of a larger particle, suggest that the redox state was not completely redistributed within the impact melts. These local signatures are compatible with precursors that could have been close to primitive matrix material of chondrites or to chondritic interplanetary dust particles. On average, the fine-grained material from Wild 2 displays a molar fraction (Fe2+oxide+Fe3+oxide)/(total Fe) equal to 0.80±0.10. It appears more oxidized than the average value measured for the comet, when done on larger particles (Westphal et al., 2009). This fine-grained material from Wild 2 does not seem to have sampled reducing environments in the solar nebulae in contrast with the larger particles of Wild 2. This observation confirms the high degree of diversity of materials in Wild 2 and is in good agreement with the dual distribution of high temperature minerals and matrices in carbonaceous chondrites.

Synchrotron Mossbauer study of Fe-bearing pyrope at high pressures and temperatures

Iron-bearing pyrope, an abundant silicate mineral in the Earth’s upper mantle, exhibits the largest quadrupole splitting (QS) in Mössbauer spectra among all common Fe-bearing rock-forming silicate minerals at ambient conditions, with a value of ~3.5 mm/s. Knowledge regarding the hyperfine QS of mantle minerals at relevant pressures and temperatures (P-T) is needed to aid our understanding of the electronic spin and valence states of iron and local site distortion in major mantle silicate minerals. The latter, in turn, is relevant for coherent model of electronic and mechanical properties of the Earth’s mantle. Here we have measured synchrotron Mössbauer spectra (SMS) of the high-spin Fe2+ in Fe-bearing pyrope garnet with two distinct compositions, (Mg0.8Fe0.2)3Al2Si3O12 (py80alm20) and Fe3Al2Si3O12 (alm100), up to 30 GPa and 750 K. Analyses of the SMS spectra revealed that the high-spin Fe2+ ions in the distorted dodecahedral site exhibit extremely high QS of ~3.4-3.6 mm/s and relatively high chemical shifts (CS) of ~1.2-1.3 mm/s at high P-T, indicating that the Fe2+ ions remain in the high-spin state. An increase in the Fe content in the pyrope-almandine series only slightly decreases the QS and CS of the Fe2+ ions. To decipher the energy separation (Δ) between the two lowest energy levels of the 3d electrons of the Fe2+ ions in the sample, the dxy and dz 2 orbitals, the QS values of py80alm20 at high P-T were further evaluated using Huggins model. Our modeled results show that the Δ of the Fe2+ ions in py80alm20 is ~156 meV at high P-T, and may be correlated to the change of the crystal-field energy splitting (ΔC). Comparison of the QS, Δ, and ΔC values of Fe2+ ions in the distorted dodecahedral sites of pyrope and silicate perovskite indicates that the high-spin Fe2+ with the extremely high QS can remain stable at high P-T conditions, consistent with recent theoretical predictions. Our results thus contribute to our current understanding of the hyperfine parameters and spin and valence states of iron in the mantle silicate minerals at high P-T

Study on Coloration Mechanism of Chinese Ancient Ceramics by X-ray Absorption Near-edge Structure

The Fe K-edge X-ray absorption near-edge structure (XANES) spectra of a series of ceramic shards were measured by fluorescence mode to reveal the color-generating techniques of Chinese porcelain. The analysis disclosed relationships among the chemical form of the iron, the firing conditions and the colors of the ceramics. The results indicate that the coloration for different ceramics depend on the valence states of iron as the main color element in glaze and the proportion of Fe2+ and Fe3+ was attributed to the baking technology. The findings provide important information for archaeologist on the coloration researches.

EFFECTS OF THE ELECTRONIC SPIN TRANSITIONS OF IRON IN LOWER MANTLE MINERALS: IMPLICATIONS FOR DEEP MANTLE GEOPHYSICS AND GEOCHEMISTRY

We have critically reviewed and discussed currently available information regarding the spin and valence states of iron in lower mantle minerals and the associated effects of the spin transitions on physical, chemical, and transport properties of the deep Earth. A high‐spin to low‐spin crossover of Fe2+ in ferropericlase has been observed to occur at pressure‐temperature conditions corresponding to the middle part of the lower mantle. In contrast, recent studies consistently show that Fe2+ predominantly exhibits extremely high quadrupole splitting values in the pseudo‐dodecahedral site (A site) of perovskite and post‐perovskite, indicative of a strong lattice distortion. Fe3+ in the A site of these structures likely remains in the high‐spin state, while a high‐spin to low‐spin transition of Fe3+ in the octahedral site of perovskite occurs at pressures of 15–50 GPa. In post‐perovskite, the octahedral‐site Fe3+ remains in the low‐spin state at the pressure conditions of the lowermost mantle. These changes in the spin and valence states of iron as a function of pressure and temperature have been reported to affect physical, chemical, rheological, and transport properties of the lower mantle minerals. The spin crossover of Fe2+ in ferropericlase has been documented to affect these properties and is discussed in depth here, whereas the effects of the spin transition of iron in perovskite and post‐perovskite are much more complex and remain debated. The consequences of the transitions are evaluated in terms of their implications to deep Earth geophysics, geochemistry, and geodynamics including elasticity, element partitioning, fractionation and diffusion, and rheological and transport properties.

Triclinic Na2−xFe1+x/2P2O7/C glass-ceramics with high current density performance for sodium ion battery

Triclinic Na2−xFe1+x/2P2O7/C composite was prepared by glass-ceramics method. We found that Na2−xFe1+x/2P2O7/C composite can be used as cathode active materials for Sodium ion battery with high current density rate performance over 10C (2 mA cm−2) condition and stable electrochemical cycle performance. A 2 μm glass precursor powder in composition of Na2−xFe1+x/2P2O7 (x = 0–0.44) was crystallized in tubular furnace around 600 °C with carbon source to reduce iron valence state and to coat grain surface with carbon. By means of charge–discharge testing Na2FeP2O7/C composite exhibits 86 mAh g−1 (253 Wh kg−1) as reversible discharge energy density that is half amount of that for LiFePO4, however in 10C condition they kept 45 mAh g−1 (110 Wh kg−1) even in 2 μm grain size.

Performances of an 80–200 kV microscope employing a cold-FEG and an aberration-corrected objective lens

The performances of a newly developed 80-200 kV cold field emission gun (CFEG) transmission electron microscope (TEM) integrating a spherical aberration corrector for a TEM image-forming lens have been evaluated. To begin, we show that the stability of both emission and probe currents makes use of this new CFEG much friendlier. The energy spread of electrons emitted from the CFEG has been measured as a function of emission current and shows a very last 0.26 eV energy resolution at 200 kV and even 0.23 eV at 80 kV. The combination of the CFEG and the CEOS™ aberration corrector, associated with enhanced mechanical and electrical stabilities of this new microscope, allows reaching an information transfer below 75 pm at 200 and 80 pm at 80 kV. This unseen resolution at 200 kV has allowed us to study the structure of CoPt nanoparticles by observing direct images of their atomic arrangement along the high indexes zone axis. We have evidenced the presence of defects in these nanostructures that are not parallel to the electron beam. The precise stoichiometry of two iron oxides, FeO and Fe2O3, has been determined from an analysis of iron valence state that was obtained from a direct analysis of EELS fine structures spectrum of the two oxides.

METAL AND METAL-SULPHIDE CONTAINING CARBONS FROM SULPHONATED STYRENE-DIVINYLBENZENE COPOLYMER BASED ION-EXCHANGERS

A temperature controlled carbonization process (5-800 °C for 1-4 h) of metal forms of various types of partially or completely saturated sulphonated styrene-divinylbenzene copolymer based ion-exchangers loaded with various valence state metal ions has been evaluated. The effect of temperature, nature and valence of metal ions, cross-linking and other parameters on the composition and properties of the synthesised composites have been evaluated. Depending on the ionic form and the degree of saturation of the ion exchangers the sulphur content of the ion-exchangers can partially transform into metal sulphides, SO 3 or SO 2 . Ni(II), Mn(II) and Zn(II) forms of the ion-exchangers resulted the appropriate M II S type metal sulphides (NiS, MnS or ZnS), while copper(II) resulted metallic copper formation at 500 °C in 2 h. Both iron(II) and iron(III) forms of sulphonated styrene-divinylbenzene copolymers resulted Fe 0.95 S and a-Fe formation at 800 °C for 2 h, however, the ratio of these compounds depended on the valence state of iron and were found to be 8:1 and 7:2 in the case of Fe(III) and Fe(II)-forms, respectively. The shape of the so formed carbon particles are bead-like and the hardness of the formed carbon beads proportional with the divinylbenzene content of the starting polymer. The higher divinylbenzene content the harder beads of carbon forms. All the beads have a leakage path due to evolution of gases which emitted at the weakest part of ball-like bead. The ball-like metal-containing activated carbon beads have low hydrodynamic resistance towards fluid streams and this carbonisation method can be used as an environmentally friendly way for processing of waste ion-exchangers into industrially usable carbon based metallic containing composites.