Iron Oxide Phases Research Articles

Thermally stimulated iron oxide transformations and magnetic behaviour of cerium dioxide/iron oxide reactive sorbents

The present paper is devoted to detailed study of the magnetically separable sorbents based on a cerium dioxide/iron oxide composite annealed at temperatures Ta=773K, 873K, and 973K. The X-ray diffraction and high resolution transmission electron microscopy are used to determine the phase composition and microstructure morphology. Mössbauer spectroscopy at room (300K) and low (5K) temperatures has contributed to more exact identification of iron oxides and their transformations Fe3O4→γ-Fe2O3 (ε-Fe2O3)→α-Fe2O3 in dependence on calcination temperature. Different iron oxide phase compositions and grain size distributions influence the magnetic characteristics determined from the room- and low-temperature hysteresis loop measurements. The results are supported by zero-field-cooled and field-cooled magnetization measurements allowing a quantitative estimation of the grain size distribution and its effect on the iron oxide transformations.

Climatic thresholds for pedogenic iron oxides under aerobic conditions: Processes and their significance in paleoclimate reconstruction

Abstract Iron oxides are widely distributed across the surface of the Earth as a result of the aerobic weathering of primary Fe-bearing minerals. Pedogenic iron oxides which consist mainly of hematite (Hm), goethite (Gt), maghemite (Mgh), are often concentrated synchronously in aerobic soils under low to moderate rainfall regimes. Magnetic susceptibility (χ) and redness, which respectively reflect the content of Mgh and Hm in soils, are considered reasonable pedogenic and climatic indicators in soil taxonomy and paleorainfall reconstruction. However, under high rainfall regimes, the grain growth of Mgh and transformation to Hm, combined with the prior formation of Gt under conditions of high relative humidity (RH), can result in magnetic reduction and dramatic yellowing of soils and sediments, which explains the existence of rainfall thresholds for Mgh and Hm at a large scale even before the pedogenic environment turns anaerobic. In order to capture the rainfall thresholds for Mgh and Hm occurring under aerobic conditions, we explored a tropical transect across a granitic region where the soil color turned from red to yellow under a wide rainfall range of 900–2200 mm/yr and a corresponding mean annual RH range of 77%–85%. We observed a lower rainfall threshold of ∼1500 mm/yr and a corresponding RH ∼80% for Mgh and Hm along this transect, as well as a higher rainfall threshold of ∼1700 mm/yr and a corresponding RH of ∼81% for Gt and total pedogenic iron oxides (citrate/bicarbonate/dithionite-extractable Fe, Fed). Cross-referencing with comparable studies in temperate and subtropical regions, we noted that the rainfall or RH thresholds for Fed and Hm or Mgh likewise increase with temperature. Moreover, the different thresholds for total and individual iron oxide phase indicates that a negative correlation between chemical weathering intensity and redness or χ in sediment sequences can occur under the prevalent climate regime just between their thresholds. Finally, we developed an integrated model to interpret the sequential formation of rainfall thresholds for different pedogenic iron oxides in soils and sediments with conditions from aerobic to anaerobic.

Control of the Magnetic Properties of a Magnetic Field Guidable Biocompatible Nanovehicle

Within this work a biocompatible magnetic nanovehicle which is movable in aqueous solutions by a magnetic field is presented. The nanovehicle consists of a porous silicon template and encapsulated iron oxide nanostructures. Both materials employed, porous silicon (PSi) as well as iron oxide are known to be biocompatible (1, 2). Mainly the synthesis of the nanocomposite as well as the magnetic properties of the systems will be discussed. Two routes are employed to produce various iron oxide phases of the embedded nanostructures within PSi. On the one hand, readily synthesized magnetite nanoparticles (NPs) which are superparamagnetic (SPM) due to their size, are infiltrated into the pores. On the other hand chemical deposition of iron oxide inside the PSi templates is used. The loading process of the templates depends not only on the pore-diameter/particle-size ratio but also on the particle-template interactions due to different surface treatments (e.g. as etched or oxidized PSi). Considering the chemically grown iron oxide, it does not form monodisperse particles but mainly clusters of particles. An increase of the temperature during the deposition resulted in a decrease of the coercivity which can be due to an iron oxide phase modification or due to a modification of the shape of the deposits. An adjustability of the magnetic properties of the system is achieved by a variation of the iron oxide loading within the PSi. An investigation of the iron oxide deposition dependent on the template and on the chemical parameters as well as of the magnetic properties in dependence on the particle size and on the template morphology of the nanocomposite will be presented. Temperature dependent magnetization measurements give information about the nature of the particle filling (packing density, spatial distribution), from field dependent magnetization measurements characteristics such as saturation magnetization, coercivity and remanence can be evaluated. For a sample containing a moderate filling with 8 nm Fe3O4 NPs the saturation magnetization has been estimated in using the measured hysteresis curves and considering the 1/H approach to be in the order of 6×10-3 emu/cm2. The amount of iron oxide particles inside the pores of the PSi matrices has been estimated in taking the magnetic moment of an individual iron oxide NP which is about 1.49 × 10-18 emu. In this case this leads to a number of about 1.3 × 1019 particles/cm3. The coercivity HC of the nanocomposite systems below TBdecreases with decreasing particle size which is due to SPM relaxation effects. The fabricated magnetic nanovehicles can be tuned in its magnetic behavior (e.g. coercivity, TB) due to the morphology of the template, the particle size and the filling conditions. The resulting magnetic moment of the samples is high enough to be moved within aqueous surroundings by a magnetic field of 0.1 T. (1) D. Ling, T. Hyeon, Small 9, 2013. (2) L.T. Canham, Adv. Mater. 7, 1033, 1995.

Change in the magnetic properties of nanoferrihydrite with an increase in the volume of nanoparticles during low-temperature annealing

The results of the investigation into the effect of low-temperature annealing of a powder of nanoparticles of bacterial ferrihydrite on its magnetic properties have been presented. It has been found that an increase in the time (up to 240 h) and temperature (in the range from 150 to 200°C) of annealing leads to a monotonic increase in the superparamagnetic blocking temperature, the coercive force, and the threshold field of the opening of the magnetic hysteresis loop (at liquid-helium temperatures), as well as to an increase in the magnetic resonance line width at low temperatures and in the magnetic susceptibility at room temperature. At the same time, according to the results of the analysis of the Mossbauer spectra, the annealing of ferrihydrite does not lead to the formation of new iron oxide phases. Most of these features are well consistent with the fact that the low-temperature annealing of ferrihydrite causes an increase in the size of nanoparticles, which is confirmed by the results of transmission electron microscopy studies.

Control of the Magnetic Properties of a Magnetic Field Guidable Biocompatible Nanovehicle

Within this work a biocompatible magnetic nanovehicle which is movable in aqueous solutions by a magnetic field is presented. The nanovehicle consists of a porous silicon template and encapsulated iron oxide nanostructures. Both materials employed, porous silicon (PSi) as well as iron oxide are known to be biocompatible. Two routes are employed to produce various iron oxide phases of the embedded nanostructures within PSi. On the one hand, readily synthesized magnetite nanoparticles (NPs) which are superparamagnetic (SPM) due to their size, are infiltrated into the pores. On the other hand chemical deposition of iron oxide inside the PSi templates is used. Mainly the synthesis of the nanocomposite as well as the magnetic properties of the systems will be discussed.

Thermal treatment of plasma-synthesized goethite improves Fenton-like degradation of orange II dye

Various iron oxides are used for Fenton reactions to degrade organic pollutants. The degradation efficiency may be improved by transforming an iron oxide phase to another. Here, we report on the transformation of goethite into hematite by thermal treatment at 400 °C. The products were analyzed by X-ray diffractometry, Raman spectroscopy, scanning electron microscopy and N2-physisorption. The catalytic activities were measured for orange II bleaching at initial concentration of 25 mg L−1, pH 3, catalyst concentration of 0.2 g L−1; 5 mM H2O2, 30 °C. Results show that the synthesized goethite was successfully transformed into hematite, and the specific surface area of the material increased from 134 to 163 m2 g−1. The bleaching efficiency of the orange II dye reached 100 % for the hematite product, versus 78 % for goethite. Therefore, a moderate thermal treatment of a plasma-synthesized goethite improves the catalytic oxidation of organic pollutants.

Synthesis of Chitosan-Mediated Silver Coated γ-Fe2O3 (Ag−γ-Fe2O3@Cs) Superparamagnetic Binary Nanohybrids for Multifunctional Applications

The coating of chitosan on γ-Fe2O3 (IO) nanoparticles (NPs) produces the biocompatible nanohybrids (CIO) with enhanced functionalities and optical features associated with a reduction in the average size of IO nanoclusters from 11.3 to 9.3 nm as was estimated by transmission electron microscopy (TEM). The effective capping by chitosan was shown by X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), TEM, and Brunauer–Emmett–Teller (BET) analyses. The in situ generation of Ag on the surface of CIO displays characteristic surface plasmonic resonance band resulting in a further decrease in the average size of IO nanoclusters in these binary nanohybrids (CIOMAg) to 8.1 nm involving supramolecular binding through IO and chitosan functionalities. The identification of the phases of iron oxide and Ag NPs and the effective capping of chitosan in binary nanohybrids have been analyzed by XRD, AFM, FESEM, and infrared (IR) analyses. The phase of iron oxide and the presence of Ag NPs in the binary nanohybrids are evidently revealed by X-ray photoelectron spectroscopy (XPS) analysis and also supported by Raman spectroscopy. The interactions among IO, chitosan, and Ag moieties in the binary nanohybrids have been analyzed by IR and XPS. These binary nanohybrids demonstrated superparamagnetic behavior with relatively higher saturation magnetization (72.5–75.5 emu/g) at room temperature compared to those of CIO (69.2 emu/g), which provides an important feature for their catalytic, SERS, and biomedical applications. As-synthesized binary nanohybrids exhibited fairly high catalytic efficiency for the reduction of methyl orange even at low Ag concentration (30 nM) and could be recycled up to ten cycles without any loss of efficiency. It demonstrated the antibacterial activity for model bacteria E. coli with MIC and MBC at 1.1 and 4.2 μg/mL Ag, respectively, and SERS activity for model dye p-ATP with a detection limit at 10 pM, evidently suggesting their environmental and biomedical potential.

A Metastable Ion (III) Oxide Phase (ε-Fe<sub>2</sub>O<sub>3</sub>): Preparation and Gas Sensing Properties

ε-Fe2O3 is a rare and metastable iron (III) oxide phase. ε-Fe2O3/SiO2 composites were prepared by combining the reverse-micelle and sol-gel methods. An appropriate amount of Ba2+ was needed in this system to promote the formation of ε-Fe2O3 nanorods in SiO2. The size of nanorods varied with different Ba2+ addition amount and sintering procedure. Then pure ε-Fe2O3 nanorods were obtained after stripping SiO2 by etching due to NaOH aqueous solution. The as-synthesized ε-Fe2O3 nanorods were discussed using X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). Interestingly, metastable ε-Fe2O3 nanorods showed a promising performance for the response for ethanol, compared with the stable phases of α-Fe2O3 and γ-Fe2O3. It indicates that nanostructure ε-Fe2O3 (including ε-Fe2O3 nanorods) could be a valuable material for the fabrication of advanced sensing devices.

Dynamics of CrO3–Fe2O3 Catalysts during the High-Temperature Water-Gas Shift Reaction: Molecular Structures and Reactivity

A series of supported CrO3/Fe2O3 catalysts were investigated for the high-temperature water-gas shift (WGS) and reverse-WGS reactions and extensively characterized using in situ and operando IR, Raman, and XAS spectroscopy during the high-temperature WGS/RWGS reactions. The in situ spectroscopy examinations reveal that the initial oxidized catalysts contain surface dioxo (O═)2Cr6+O2 species and a bulk Fe2O3 phase containing some Cr3+ substituted into the iron oxide bulk lattice. Operando spectroscopy studies during the high-temperature WGS/RWGS reactions show that the catalyst transforms during the reaction. The crystalline Fe2O3 bulk phase becomes Fe3O4 ,and surface dioxo (O═)2Cr6+O2 species are reduced and mostly dissolve into the iron oxide bulk lattice. Consequently, the chromium–iron oxide catalyst surface is dominated by FeOx sites, but some minor reduced surface chromia sites are also retained. The Fe3–-xCrxO4 solid solution stabilizes the iron oxide phase from reducing to metallic Fe0 and imparts ...

Chondroitin sulfate-capped super-paramagnetic iron oxide nanoparticles as potential carriers of doxorubicin hydrochloride

Chondroitin-4-sulfate (CS), a glycosaminoglycan, was used to prepare CS-capped super-paramagnetic iron oxide nanoparticles, which were further employed for loading a water-soluble chemotherapeutic agent (doxorubicin hydrochloride, DOX). CS-capped SPIONs have potential biomedical application in cancer targeting. The optimized formulation had a hydrodynamic size of 91.2±0.8nm (PDI; 0.228±0.004) and zeta potential of −49.1±1.66mV. DOX was loaded onto the formulation up to 2% (w/w) by physical interaction with CS. TEM showed nano-sized particles having a core-shell structure. XRD confirmed crystal phase of iron oxide. FT-IR conceived the interaction of iron oxide with CS as bidentate chelation and also confirmed DOX loading. Vibration sample magnetometry confirmed super-paramagnetic nature of nanoparticles, with saturation magnetization of 0.238emug−1. In vitro release profile at pH 7.4 showed that 96.67% of DOX was released within 24h (first order kinetics). MTT assay in MCF7 cells showed significantly higher (p<0.0001) cytotoxicity for DOX in SPIONs than DOX solution (IC50 values 6.294±0.4169 and 11.316±0.1102μgmL−1, respectively).

Novel chitosan goethite bionanocomposite beads for arsenic remediation

We report on the synthesis and As adsorption properties of a novel chitosan – iron (oxyhydr)oxide composite material for the remediation of arsenic-contaminated water supplies. FE-SEM, Mössbauer spectroscopy, ICP-OES and synchrotron (Bulk XAS, μXRF) techniques were applied to determine the composition of the new material and investigate the As uptake efficiency and mechanism. The iron (oxyhydr)oxide phase has been identified as a nano-sized goethite, well dispersed in the chitosan matrix, leading to the name ‘chitosan goethite bionanocomposite’ (CGB). The CGB material is prepared in the form of beads of high density and excellent compression strength; the embedding of the goethite nanoparticles in the chitosan matrix allows for the high adsorption capacity of nanoparticles to be realized. CGB beads remove both As(III) and As(V) efficiently from water, over the pH range 5–9, negating the need for pre-oxidation of As(III). Kinetic studies and μXRF analysis of CGB bead sections show that diffusion-adsorption of As(V) into CGB beads is faster than for As(III). Using CGB beads, synthetic high-arsenic water (0.5 mg-As/L) could be purified to world drinking standard level (<0.01 mg-As/L) using only 1.4 g/L CGB. When considered in combination with the advantages of the low-cost of raw materials required, and facile (green) synthesis route, CGB is a promising material for arsenic remediation, particularly in developing countries, which suffer a diversity of socio-economical-traditional constraints for water purification and sanitation.

In situ Raman spectroscopy evidence of an accessible phase potentially involved in the enhanced activity of La-deficient lanthanum orthoferrite in 3-way catalysis (TWC)

We report here on an in situ Raman investigation of stoichiometric and La-deficient LaFeO3 solids along model treatments related to three-way catalysis. Whereas the Raman signature of the stoichiometric compound is only slightly modified by the sequence we have applied, the reversible formation of a new phase based on Fe2IIIO3 in the La-deficient solid was evidenced. This new phase was found to be stabilized under the same experimental conditions which also favor the volumetric expansion of the LFO unit cell. Eventually, this new iron oxide phase was found to be reduced under CO/He mixture and subsequently regenerated under NO.

The application of catalyst-recovered SnO2 as an anode material for lithium secondary batteries.

We studied the electrochemical characteristics of tin dioxide (SnO2) recovered from waste catalyst material which had been previously used in a polymer synthesis reaction. In order to improve the electrochemical performance of the SnO2 anode electrode, we synthesized a nanocomposite of recovered SnO2 and commercial iron oxide (Fe2O3) (weight ratio 95:5) using a solid state method. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) analyses revealed an additional iron oxide phase within a porous nanocomposite architecture. The electrochemical characterizations were based on galvanostatic charge-discharge (CD) curves, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). In the first discharge, the capacity of the SnO2-Fe2O3 nanocomposite was 1700mAhg(-1), but was reduced to about 1200mAhg(-1) in the second discharge. Thereafter, a discharge capacity of about 1000mAhg(-1)was maintained up to the 20th cycle. The SnO2-Fe2O3 nanocomposite showed better reversible capacities and rate capabilities than either the recovered SnO2 or commercial Fe2O3 nanoparticle samples.

Development of a biocompatible magnetic nanofluid by incorporating SPIONs in Amazonian oils

Higher quality magnetic nanoparticles are needed for use as magnetic nanoprobe in medical imaging techniques and cancer therapy. Moreover, the phytochemistry benefits of some Amazonian essential oils have sparked great interest for medical treatments. In this work, a magnetic nanoprobe was developed, allying the biocompatibility and superparamagnetism of iron oxide nanoparticles (SPIONs) with benefits associated with Amazonian oils from Copaiba and Andiroba trees. SPIONs were obtained by two thermal decomposition procedures and different amounts of precursors (iron acetylacetonates). Their characterization was accomplished by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy (TEM), X-ray diffraction (XRD), Mössbauer spectroscopy and magnetization. The obtained nanoparticles composition and magnetic properties were not affected by the relative proportion of iron(II) and iron(III) in the precursor system. However, when changing the reducing and stabilizing agents the coating layer shows different compositions/relative weight — the more promising SPIONs have a coating mainly composed by oleylamine and an iron oxide:coating wt% ratio of 55:45. Nanoparticles size distributions were very narrow and centred in the average size of 6–7nm. Cellular assays confirmed the biocompatibility of SPIONs and their effective internalization in human colon cancer cells. Mössbauer/XRD results indicated maghemite as their main iron oxide phase, but traces of magnetite proved to be present. Magnetization saturations of 57emu/g at 5K and 42emu/g at 300K were achieved. With incorporation of SPIONs into Copaiba and Andiroba essential oils, these values show a 4-fold decrease, but the supermagnetic behaviour is preserved providing the effective formation of a nanofluid.

Evolution of magnetic and bone mineral phases in heat‐treated bioactive glass containing zinc and iron oxides

Melt‐quenched 15(ZnO,Fe2O3) 50SiO2·20(CaO,P2O5) 15Na2O bioactive glass was heat treated at temperatures (TA) ranging from 550°C to 850°C for different time periods (tA=1, 2 and 3 hours) to understand its devitrification characteristics. Crystallization of calcium sodium phosphate, zinc ferrite, magnetite, and hematite phases depended on heat treatment conditions. Decrease in saturation magnetizations (Ms) with increase in tA of glass heat treated at TA≥750°C is attributed to the formation of hematite which is a weak magnetic material. Magnetic properties as functions of TA and tA are interpreted on the basis of clustering of Fe ions, super‐exchange interaction between Fe2+ and Fe3+ ions and formation of ferrimagnetic and weakly magnetic iron oxide phases with different heat treatment conditions. Electron paramagnetic resonance parameters reveal the variations in site distortions and randomness in Fe ion environment in the matrix upon heat treatment. In vitro mineralization ability of the glass‐ceramics was evaluated by immersion in simulated body fluid (SBF) and monitoring both the pH variation of SBF and formation of hydroxyapatite surface layer as a function of immersion time. These studies help in assessing these glass‐ceramics for hyperthermia treatment and in optimizing the processing conditions for this application.

Iron Nanoparticles Fabricated by High-Energy Ball Milling for Magnetic Hyperthermia

Iron nanoparticles (FeNPs) have been successfully prepared by high-energy ball milling in air for various milling times from 1 h to 32 h. Their structure, particle size, elemental composition, magnetic, and inductive heating properties were investigated by means of x-ray diffraction (XRD) analysis, field-emission scanning electron microscopy, energy-dispersive x-ray (EDX) spectroscopy, vibrating-sample magnetometry, and magnetic induction heating, respectively. XRD analysis showed that the average crystallite size decreased to 11 nm after 10 h of milling, then remained almost unchanged for longer milling times. Coexistence of iron (Fe) and iron oxide (FeO) phases was detected after 12 h of milling. EDX analysis also confirmed the occurrence of oxidation, which can be reconciled with the corresponding decrease and increase in saturation magnetization (Ms) with milling time when exposed to oxygen and when annealed under H2 ambient due to oxygen reduction. The time-dependent magnetic and inductive heating responses of the FeNPs were investigated for prospective application in magnetic hyperthermia. The effect of varying the alternating-current (AC) magnetic field strength on the saturation heating temperature and specific loss power of FeNP-containing ferrofluid with concentration of 4 mg/mL was also studied and is discussed.

Crude Oil Metabolites in Groundwater at Two Spill Sites.

Two groundwater plumes in north central Minnesota with residual crude oil sources have 20 to 50 mg/L of nonvolatile dissolved organic carbon (NVDOC). These values are over 10 times higher than benzene and two to three times higher than Diesel Range Organics in the same wells. On the basis of previous work, most of the NVDOC consists of partial transformation products from the crude oil. Monitoring data from 1988 to 2015 at one of the sites located near Bemidji, MN show that the plume of metabolites is expanding toward a lakeshore located 335 m from the source zone. Other mass balance studies of the site have demonstrated that the plume expansion is driven by the combined effect of continued presence of the residual crude oil source and depletion of the electron accepting capacity of solid phase iron oxide and hydroxides on the aquifer sediments. These plumes of metabolites are not covered by regulatory monitoring and reporting requirements in Minnesota and other states. Yet, a review of toxicology studies indicates that polar metabolites of crude oil may pose a risk to aquatic and mammalian species. Together the results suggest that at sites where residual sources are present, monitoring of NVDOC may be warranted to evaluate the fates of plumes of hydrocarbon transformation products.

Comparative study of biogenic and abiotic iron-containing materials

Series of iron-based biogenic materials prepared by cultivation of Leptothrix group of bacteria in different feeding media (Sphaerotilus-Leptothrix group of bacteria isolation medium, Adler, Lieske and silicon-iron-glucose-peptone) were studied. Control samples were obtained in the same conditions and procedures but the nutrition media were not infected with bacteria, i.e. they were sterile. Room and low temperature Mossbauer spectroscopy, powder X-ray diffraction (XRD), and infrared spectroscopy (IRS) were used to reveal the composition and physicochemical properties of biomass and respective control samples. Comparative analysis showed differences in their composition and dispersity of present phases. Sample composition included different ratio of nanodimensional iron oxyhydroxide and oxide phases. Relaxation phenomena such as superparamagnetism or collective magnetic excitation behaviour were registered for some of them. The experimental data showed that the biogenic materials were enriched in oxyhydroxides of high dispersion. Catalytic behaviour of a selected biomass and abiotic material were studied in the reaction of CO oxidation. In situ diffuse-reflectance (DR) IRS was used to monitor the phase transformations in the biomass and CO conversion.

Amorphous iron phases in medium temperature leach residues and associated metal loss

Leach residues, produced during pilot and demonstration scale medium temperature (150°C) hydrometallurgical processing of sulfide ores contain amorphous/poorly crystalline and metastable nano-scale iron oxides/oxyhydroxide phases. These phases control the properties of the residue and contain a relatively high loading of the valuable (Cu, Ni) metals. Residue samples from CESL and Vale pilot and demonstration plant medium temperature processes were characterized using different techniques. Poor agreement between total iron analysis by inductively coupled plasma mass spectroscopy (ICP-MS) and quantitative X-ray powder diffraction QXRPD indicated the presence of amorphous/poorly crystalline iron oxide phases. QXRPD coupled with sequential extraction was used for quantification of the amorphous iron phases. Amorphous iron oxides/oxyhydroxides were found to be a major source of copper and nickel losses to the residue. The distribution of copper and nickel into the amorphous and crystalline iron oxide phases was determined by a two-stage sequential extraction process. Association of copper and nickel to the amorphous phases was found to be approximately 2–4 times higher than with the crystalline iron oxide phases.

Studies of the Colloidal Properties of Superparamagnetic Iron Oxide Nanoparticles Functionalized with Platinum Complexes in Aqueous and PBS Buffer Media

This work has focused on the synthesis of three nanosystems composed of superparamagnetic iron oxide nanoparticles (SPIONs) coated either with a carboxylate platinum(IV) complex (PD = cis,cis,trans-[Pt(NH3)2Cl2(HOOCCH2CH2COO)(OH)]) or with platinum(II) complex functionalized dextrans (DexPt1 = [Pt(Dex-NH2)Cl3] and DexPt2 = [Pt(Dex-NH2)(NH3)2(H2O)]). All nanosystems have shown superparamagnetic behavior. Powder X-ray diffraction (XRD) has confirmed that the SPIONs were iron oxide phase and transmission electron microscopy (TEM) has shown average size of 6 nm (M6). Characterization of the nanosystems by inductively coupled plasma atomic emission spectroscopy (ICP AES) has revealed the presence of platinum on their surface (M6@PD, 0.54 mmol g-1 of Fe and M6@CA@DexPt1-2, 0.32-1.20 mmol g-1 of Fe); infrared spectroscopy (IR) and thermogravimetric and differential thermal analyses (TG-DTA) have confirmed the presence of dextran. Furthermore, the colloidal properties of these nanosystems (M6@PD and M6@CA@DexPt1-2) have been evaluated in water and in PBS buffer. Although M6@PD has shown good colloidal dispersion in water in the pH range of 2.0-8.0, the system underwent rapid agglomeration in PBS buffer. The M6@CA@DexPt1-2 nanosystems have exhibited improved colloidal behavior both in water and in PBS, where hydrodynamic sizes were kept below 100 nm over a large pH range (2.0-12.0). Furthermore, the latter systems have displayed isoelectric points below pH 5.0 and low surface charges at pH 7.0 (ζ-potential = -10 mV) and therefore PBS did not affect their colloidal stability.