Potassium Ferrocyanide Research Articles

Partially graphitic nanoporous activated carbon prepared from biomass for supercapacitor application

In this present work, the preparation of partially graphitic nanoporous carbon from biomass (bamboo bagasse) is carried out using potassium ferrocyanide and -KOH as activating agent with controlled temperature and gas flow rates. The physico-chemical properties of biomass-derived graphitic nano-porous carbon were characterized by X-ray Diffraction (XRD), Fourier Transform Infra-Red Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), Raman spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and electrochemical measurements. It is interesting that the activation with the iron salts plays a significant role in the formation of graphitic structures. The graphitic nanoporous carbonaceous materials show high specific surface area of 1360 m2 g−1, low impedance, large pore volume and high specific capacitance. Thus, the iron-catalyzed graphitic carbon is excellent candidate for the supercapacitor applications. This contemporary- novel method to synthesis of nanoporous carbon represents a great potential for apparent and diversified applications in energy storage materials.

A facile photoelectrochemical sensor for high sensitive ROS and AA detection based on graphitic carbon nitride nanosheets

Photoactive material is one of the main challenges for fabrication of sensitive and selective photoelectrochemical (PEC) sensor. Herein, a facile PEC sensor is constructed using graphitic carbon nitride nanosheets (g-C3N4 NSs) coated on the surface of ITO electrode, where electron donor properties of potassium ferrocyanide and ascorbic acid is utilized for the tracing of hydrogen peroxide (H2O2), hypochlorite (ClO-), and ascorbic acid (AA). Our designed PEC sensor exhibits a good linear range to H2O2 concentrations from 12.5 to 875 µM in pH = 7.4 and 2.5–400 µM in pH = 10, while that for AA is in the range from 0.25 to 100 µM in pH = 7.4, and with the same pH for ClO- concentrations in the range from 0.5 to 19 × 10−3% (V/V) in a bleach sample. Owing to the good responses towards the traces of H2O2, AA, and ClO-, our designed system may be used as H2O2, ClO-, and AA sensor for outdoor applications with high specificity, long-time stability and good reproducibility.

Electrochemical behavior of polycrystalline gold electrode modified by thiolated calix[4]arene and undecanethiol

The electrochemical behavior of polycrystalline gold electrode (PAuE) modified by self-assembled monolayers (SAMs) of thiolated calix[4]arene (C4A) and undecanethiol (C11) was investigated by voltammetric methods and electrochemical impedance spectroscopy.Coverage of the thiol SAMs and their stability was tested. The C11 layer is very stable; the desorption peak was recorded only in basic solutions of pH 12 and higher (at −1.30 V vs. Ag|AgCl (3 mol L−1 KCl)).The position of the C4A desorption peak is more pH dependent and it was recorded at −1.08 V at pH 13. Molecular coverage for C4A and C11 SAMs modified PAuE is 364 ± 52.9 μC cm−2 and 137 ± 20.0 μC cm−2 respectively.The properties of the PAuE modified by C11 and/or C4A were investigated using the model compounds hydroquinone, ferrocene and potassium ferrocyanide. It is assumed that the oxidation of the hydroquinone cannot be realized inside the C4A cavity because the hydroquinone molecule is too big to enter the cavity. Similar behavior was observed using potassium ferrocyanide.In contrast, cyclic voltammograms of ferrocene oxidation were only negligibly affected by the electrode modification. Moreover, capacitance measurements proved accumulation of ferrocenium ions at the C4A modified electrode.

Production of mono- to few-layer MoS2 nanosheets in isopropanol by a salt-assisted direct liquid-phase exfoliation method

Here, we report a facile salt-assisted direct liquid-phase exfoliation method for mass production of MoS2 nanosheets. We choose organic solvent isopropanol (IPA) as exfoliation media and potassium ferrocyanide, potassium sodium tartrate, or sodium tartrate as salt, the assistant. The selected salts show universal and efficient assistant effect for the exfoliation of MoS2 in IPA. Especially, potassium ferrocyanide (K4Fe(CN)6) can enhance the exfoliation efficiency up to 73 times and a dispersion of MoS2 nanosheets with concentration as high as 0.240 mg mL−1 can be easily obtained in IPA-K4Fe(CN)6 system. Transmission electron microscopy, atomic force microscopy (AFM), and Raman spectroscopy show that bulk MoS2 has been successfully exfoliated into mono- to few-layer MoS2 nanosheets. AFM analysis indicates that nearly 60% flakes are monolayer in MoS2 dispersion.

Metal Incorporated Polymeric Nanodots Based Electrode Material for Fluorescent Supercapacitors

In this article, a new class of fluorescent supercapacitor electrode material has been developed by electro-polymerization of Rhodamine b dye in presence of Potassium Ferrocyanide on pencil graphite electrode. The morphology and surface properties of plain polymeric Rhodamine nanodots and Potassium Ferrocyanide incorporated polymeric Rhodamine nanodots were analyzed. Optical and electronic properties of Potassium Ferrocyanide incorporated polymeric Rhodamine b nanodots was found to be superior in comparison with polymeric Rhodamine b nanodots. Potassium Ferrocyanide incorporated polymeric Rhodamine b nanodots shows an enhanced specific conductance (320.0 F/g), and better rate capability 3 to 4 times higher than the plain polymeric Rhodamine b nanodots modified graphite electrodes. The electrochemical activity of the fluorescent Potassium Ferrocyanide doped polymeric Rhodamine b nanodots was found to be easily tailored by changing the concentration of Potassium Ferrocyanide. The 2:1 molar ratio (Potassium Ferrocyanide and Rhodamine b) based polymeric nanodots shows excellent specific capacitance (434.8 F g−1) and fluorescent maxima 580 nm in comparison to other mixing ratios. Potassium Ferrocyanide doped polymeric Rhodamine b nanodots possess excellent rate performance, high energy density of 150.06 Wh kg−1 at a power density of 900 W kg−1, and robust cycling durability, with 99.5% retaining in its specific capacitance even after 6500 cycles. Even after 8 months (40,000 cycles) of testing, the performance of the supercapacitor did not degrade. The excellent performance of the investigated fluorescent nanodots as electrode material could open up the application of supercapacitors to Internet of Things (IoT) applications.

Micellar and bicontinuous microemulsion structures show different solute-solvent interactions: a case study using ultrafast nonlinear infrared spectroscopy.

Microemulsions are transparent, thermodynamically stable liquid mixtures of oil, water and surfactant. They typically exist in the form of micellar and bicontinuous structures, which appear to be equilibrium systems but are actually complex in structure and are difficult to characterize at the molecular level. In this work, potassium ferrocyanide [K4Fe(CN)6] and tungsten hexacarbonyl [W(CO)6] were chosen as two probe molecules for water and organic phases respectively to simultaneously explore the structures and dynamics of commonly prepared reverse micellar and bicontinuous microemulsion structures using aerosol OT (AOT) as the surfactant and isooctane as the oil phase. Even though these two structures have quite different solvent environments due to the varying geometry and boundary conditions, the steady-state infrared spectra of the C[triple bond, length as m-dash]N- stretching mode in the water phase are quite similar, and so are those of the C[triple bond, length as m-dash]O stretching mode in the oil phase. However, vibrational and anisotropic relaxation dynamics obtained from infrared pump-probe spectroscopy and spectral diffusion dynamics extracted from two-dimensional infrared spectroscopy of the two infrared chromophores in the two probe molecules are found to be quite sensitive to whether the probe molecules are in pure solvent or in a restricted microemulsion environment. The results in the water phase and oil phase are discussed separately. Our work demonstrated that ultrafast nonlinear infrared spectroscopy can be used to differentiate the structural details at the molecular level for different microemulsion systems.

Wall-to-bed mass transfer in a three-phase fluidized bed with coaxially placed string of spheres internal

Turbulent promoters are generally used to realize enhancement in heat and mass transfer rates. With a view to exploit this advantage for the favor of obtaining magnitudes of improvements in mass transfer rates in electrochemical processes, in the present study experiments were conducted in three phase fluidized bed electrochemical cells in the presence of coaxially placed string of spheres. Diffusion controlled electrode reactions were employed to obtain limiting current densities, and hence, mass transfer coefficients. An equimolar potassium ferrocyanide and potassium ferricyanide solution in the presence of sodium hydroxide supporting electrolyte was used as the liquid phase. Glass spheres of different sizes were employed as fluidizing solids and nitrogen was used as the inert gas phase. In three phase fluidized bed, mass transfer coefficient increased with increasing sphere diameter and particle diameter. The parametric effect of gas and liquid velocities on mass transfer coefficient was found to be marginal. The mass transfer coefficient was found to decrease with increase in pitch. A correlation to predict mass transfer coefficient has been developed by using least squares regression analysis.

Reduced graphene oxide/polyethylenimine based immunosensor for the selective and sensitive electrochemical detection of uropathogenic Escherichia coli

Fast, reliable and selective detection of microorganisms is of uttermost importance in clinical analysis, but also in food and water quality monitoring. In this study, we report on the construction of an immunosensor for sensitive and selective electrochemical detection of uropathogenic Escherichia coli (E. coli) UTI89 bacteria in aqueous and serum samples. We took benefit of electrophoretic deposition (EPD) to prepare, in a simple, controllable and cost effective way, gold electrodes modified with thin active layers of reduced graphene oxide/polyethylenimine (rGO/PEI). While rGO exhibits high surface area and favourable electrochemical properties, the presence of abundant NH2 groups on PEI offers a plethora of opportunities for the sensor’s surface functionalization. To achieve selectivity of detection, the electrode surface was covalently modified with anti-fimbrial E. coli antibodies via amide bond formation. To minimize non-specific adsorption, the immunosensor was additionally modified with pyrene-polyethyleneglycol (pyrene-PEG) moieties prior to antibody immobilization. The detection of E. coli was based on the restriction of electron transfer of a redox mediator, in our case potassium ferrocyanide, to the rGO/PEI modified electrical transducer due to the formation of an immune complex. The developed immunosensor displayed a sigmoidal shape with a linear range of 1 × 101–1 × 104 cfu mL−1 (R2 = 0.995) according to i(μA) = −16.66–20.5 × log[E. coli] (cfu mL−1) and a detection limit of 10 cfu mL−1. Additionally, the sensor performed well both in aqueous, serum and urine media, which is essential for its potential use for clinical diagnosis of pathogenic diseases. Selectivity studies showed that the immunosensor was able to discriminate between E. coli UTI89 wild-type strain and UTI89 Δfim, without fim operon.

Additives-assisted electrodeposition of fine spherical copper powder from sulfuric acid solution

Metal removal and recovery from wastewater is of great importance for the environmental protection and resources sustainability. In this study, the synergistic effect of additives towards the electrochemical recovery of Cu was illustrated using low-cost stainless steel cathode. It has been identified that potassium ferrocyanide has the effect of grain refining, and 2, 2′-dipyridine has the effect of spherical growth. Therefore, fine spherical copper deposited product is firstly obtained in the presence of two target-specific additives from dilute solution, and satisfied current efficiency is achieved. This additives-assisted electrodeposition approach may serve as a promising alternative to overcome the bottlenecks of existing metal recovery and water purification.

Fabrication and characterization of electrochemically prepared bioanode (polyaniline/ferritin/glucose oxidase) for biofuel cell application

Porous matrix of polyaniline (PANI) has been electrodeposited along with the entrapment of biocompatible redox mediator ferritin (Frt) and glucose oxidase (GOx) on the surface of glassy carbon (GC) electrode. The characterizations have been carried out by X-ray Diffraction (XRD) and Transmission electron microscopy (TEM). The enhanced electrochemical signal transfer rate from enzyme to the electrode surface was due to the intimate contact of the enzyme with the electrochemically polymerized conducting PANI matrix. The PANI/Frt/GOx modified GC bioanode was used to investigate the electrocatalytic activity as a function of the concentration of glucose in the range of 10–60 mM. It was confirmed by the electrochemical impedance spectroscopy (EIS), the thick deposition of PANI layer becomes more compact due to which the charge transfer resistance of PANI matrix becomes higher. All the electrochemical measurements of the electrode were carried out by using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). CV curves were recorded at different scan rates (20–100 mV/s) at 50 mM of glucose in 0.3 M potassium ferrocyanide. A normalized saturation current density of 22.3 ± 2 mA/cm2 was observed for the oxidation of 50 mM glucose at a scan rate of 100 mV/s.

Alkaline Benzoquinone Aqueous Flow Battery for Large‐Scale Storage of Electrical Energy

AbstractAn aqueous flow battery based on low‐cost, nonflammable, noncorrosive, and earth‐abundant elements is introduced. During charging, electrons are stored in a concentrated water solution of 2,5‐dihydroxy‐1,4‐benzoquinone, which rapidly receives electrons with inexpensive carbon electrodes without the assistance of any metal electrocatalyst. Electrons are withdrawn from a second water solution of a food additive, potassium ferrocyanide. When these two solutions flow along opposite sides of a cation‐conducting membrane, this flow battery delivers a cell potential of 1.21 V, a peak galvanic power density of 300 mW cm−2, and a coulombic efficiency exceeding 99%. Continuous cell cycling at 100 mA cm−2 shows a capacity retention rate of 99.76% cycle−1 over 150 cycles. Various molecular modifications involving substitution for hydrogens on the aryl ring are implemented to block decomposition by nucleophilic attack of hydroxide ions. These modifications result in increased capacity retention rates of up to 99.96% cycle−1 over 400 consecutive cycles, accompanied by changes in voltage, solubility, kinetics, and cell resistance. Quantum chemistry calculations of a large number of organic compounds predict a number of related structures that should have even higher performance and stability. Flow batteries based on alkaline‐soluble dihydroxybenzoquinones and derivatives are promising candidates for large‐scale, stationary storage of electrical energy.

The current level of β-radioactivity in the Zaporizhzhya storage lake

The condition control of the Ukrainian rivers is an integral part of the population safety level. The change of such state can occur for several reasons. The first is the increase of pollution level from the working enterprises. The second – the efficiency reduction of protective constructions which store the radioactive wastes of (tailings dam). And the third – movement changes of water masses which are capable to lift the radio nuclides received earlier from the river bed (for example, the accident on the Chernobil atomic station). Therefore, the aim of the work was the modern level evaluation of b-nuclide pollution (90Sr and 137Cs) in water of Zaporizhzhya storage lake on the largest density points of the industrial enterprises on the Dnieper river in the sequence Kamenskoe – Dnipro – Zaporizhzhya at different seasons of the three years. Within 2014–2016 we carried out investigations of Zaporizhzhya storage lake b-radiation level for different seasons. The sampling was made at depth from 1,0 m to 1,5 m on six points. These points corresponded to the coast ones of Zaporizhzhya storage lake which are bound up with the industrial enterprises wastes of Kamenskoe and Dnipro or the small rivers fall points into the Dnieper River. The sampling points were: a coastal area 200 m below the Dneprodzerzhinsky dam, the river port, Starie Kodaki, the mouth of the river Mokra Sura, village Vojskove and Fyodorivka. The water mass of 5 kg was taken from these points and poured into the glass bottles. For radioactive pollution level determination in river's points we used two samples by 60 dm3 volume or caesium (137Cs) and strontium (90Sr) definition. 90Sr activity in water was determined radiochemically by oxalates sedimentation method with the subsequent measurement on the UMF-1500 installation. The isotope 137Cs was besieged by potassium ferrocyanide from a muriatic solution with the subsequent measurement on a small background installation The general β-radioactivity (Bq/l) was determined in the samples on the radiometer-«Beta» with the help of the SBT-13 counter by direct measurement method of samples. We showed that the levels of general β-activity water or at the investigated selection points of Zaporizhzhya storage lake fluctuated on average from 0,14 to 0,24 Bq/l, the content of 90Sr radionuclides in water is from 0,029 to 0,055 Bq/l, for 137Cs – is 0,042 Bq/l. In autumn β-activity level in Zaporozhzhya storage lake water decreased in comparison with spring – summer seasons. It is typical for storage lakes with a superficial filling which is followed by a relative increase of radioactive materials in water from deeply lying breeds bottom. For 90Sr, the effect of fluctuations in its concentration is observed, depending on the presence of industrial centers on the way of water movement along the Zaporizhzhya Reservoir. This effect not marked for 137Cs. An assessment of the level of water pollution has shown that in our time the indicators of the studied isotopes do not exceed the permissible levels of radioactivity stipulated by the norms of radiation safety of Ukraine from 1997.

Graphene oxide electrochemistry: the electrochemistry of graphene oxide modified electrodes reveals coverage dependent beneficial electrocatalysis.

The modification of electrode surfaces is widely implemented in order to try and improve electron transfer kinetics and surface interactions, most recently using graphene related materials. Currently, the use of ‘as is’ graphene oxide (GO) has been largely overlooked, with the vast majority of researchers choosing to reduce GO to graphene or use it as part of a composite electrode. In this paper, ‘as is’ GO is explored and electrochemically characterized using a range of electrochemical redox probes, namely potassium ferrocyanide(II), N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD), dopamine hydrochloride and epinephrine. Furthermore, the electroanalytical efficacy of GO is explored towards the sensing of dopamine hydrochloride and epinephrine via cyclic voltammetry. The electrochemical response of GO is benchmarked against pristine graphene and edge plane-/basal plane pyrolytic graphite (EPPG and BPPG respectively) alternatives, where the GO shows an enhanced electrochemical/electroanalytical response. When using GO as an electrode material, the electrochemical response of the analytes studied herein deviate from that expected and exhibit altered electrochemical responses. The oxygenated species encompassing GO strongly influence and dominate the observed voltammetry, which is crucially coverage dependent. GO electrocatalysis is observed, which is attributed to the presence of beneficial oxygenated species dictating the response in specific cases, demonstrating potential for advantageous electroanalysis to be realized. Note however, that crucial coverage based regions are observed at GO modified electrodes, owing to the synergy of edge plane sites and oxygenated species. We report the true beneficial electrochemistry of GO, which has enormous potential to be beneficially used in various electrochemical applications ‘as is’ rather than be simply used as a precursor to making graphene and is truly a fascinating member of the graphene family.

Replicate Imaging of a Unicellular Plant through a GlassBarrier Using Fine Iron Particles: Evidence for Electromagnetic Energy Transfer

Introduction: Previously we utilized a method for imaging electromagnetic fields from plant and animal tissues. We applied the same methodology to single cell organisms.Methods: A clean glass slide served as a base. A coverslip was placed on the base. A drop of culture media containing the single cell plant, Euglena gracilis was placed on the coverslip and covered by another coverslip to enclose the organisms. A second coverslip “sandwich” (SDW) containing fine iron particles (mean diameter 2 microns) mixed with a potassium ferrocyanide iron staining solution was placed over the underlying coverslip SDW. The second SDW was offset so that a portion was not covering the area with the microorganism, thereby serving as a control. When all of the liquid had evaporated (24 - 48 hours) the area encompassed by the images of the encysted cells were quantified using the Image Pro-plus histomorphometry software program and compared to similar images of actual encysted cells from dried specimens for the same time periods (each group, n = 5).Results: Initially we observed mobile, rod shaped, single cell organisms with rounded ends. After 24 - 48 hours, the second coverslip showed images of the immobile of encysted, cells whose appearances were identical and whose area measurements were not significantly different (p ≥ 0.6) than the actual encysted cells.Conclusions: These finding demonstrate that replicate images of the single cell plant, Euglena gracilis, can be retrieved through a glass barrier. The evidence suggesting that electromagnetic energy may provide a possible mechanism underlying these replicate images is illustrated and discussed.

A Hydrogen Peroxide Biosensor Based on the Immobilization of the Highly Stable Royal Palm Tree Peroxidase (Roystonea regia) with Chitosan and Glutaraldehyde on Screen-printed Graphene Electrodes

This paper present the fabrication and electrochemical stud-ies of a screen-printed graphene electrode (SPGE) modified with Roy-al palm tree peroxidase (RPTP) in combination with chitosan (CS) and cross-linking of glutaraldehyde (GA) for detection of hydrogen perox-ide. Cyclic voltammograms in the presence of potassium ferrocyanide ([Fe(CN)6]3-/4-) as a redox species demonstrated an increasing of 50mA evidenced by the electron transfer process of SPGE modified with CS-GA-RPTP. The graphene modified electrode exhibits excellent electrocatalytic activity to the reduction of H2O2, with a linear response in the 100 mM to 5 mM concentration range and a detection limit of 87 mM. The new sensor based on the modification of graphene electrode with the high stable RPTP will provide a potential amperometric detection system for determination of H2O2 in real samples with some biomedical or environmental importance.

Biosynthesis regulation of natamycin production from Streptomyces natalensis HDMNTE-01 enhanced by response surface methodology

ABSTRACTNatamycin has been widely applied in medical treatments and food protection widely due to its effective inhibition to the growth of yeast and mold. As polyene macrolide antibiotic, the biosynthesis pathway of natamycin is relatively clear. To regulate the biosynthesis of natamycin, additions of precursors affecting cell growth and natamycin production were investigated. The results showed that 0.003% (w/v) potassium ferrocyanide and sodium propionate: n-butanol at a ratio of 4:1 was added into the broth at 0 and 24 hr, respectively, and they contributed to yield natamycin, reaching 1.62 g L−1 (174.6% higher than control). Furthermore, response surface methodology was undertaken to enhance natamycin production by Streptomyces natalensis HDMNTE-01 (a wild strain). The optimum conditions determined were: glucose 3.97%; soya peptone 2%; yeast extract 0.5%; original pH 7.0; inoculum volume 6%; growth in a 250-mL flask containing 24.68 mL of medium; shaken (220 rpm) at 28°C for 4 days. Under the optimized conditions, the yield was 2.81 g L−1 natamycin in 5-L fermentor when the fermentation was processed.

A Newly Designed Fixed Bed Redox Flow Battery Based on Zinc/Nickel System

A fixed-bed zinc/nickel redox flow battery (RFB) is designed and developed. The proposed cell has been established in the form of a fixed bed RFB. The zinc electrode is immersed in an aqueous NaOH solution (anolyte solution) and the nickel electrode is immersed in the catholyte solution which is a mixture of potassium ferrocyanide, potassium ferricyanide and sodium hydroxide as the supporting electrolyte. In the present work, the electrode area has been maximized to 1500 cm2 to enforce an increase in the energy efficiency up to 77.02% at a current density 0.06 mA/cm2 using a flow rate 35 cm3/s, a concentration of the anolyte solution is 1.5 mol L-1 NaOH and the catholyte solution is 1.5 mol L-1 NaOH as a supporting electrolyte mixed with 0.2 mol L-1 equimolar of potassium ferrocyanide and potassium ferricyanide. The outlined results from this study are described on the basis of battery performance with respect to the current density, velocity in different electrolytes conditions, energy efficiency, voltage efficiency and power of the battery. Keywords: Fixed bed, Redox flow battery, Energy storage, Zinc/nickel RFB, Cost analysis

Titania coated silica microsphere functionalized with potassium ferrocyanide impregnated in calcium alginate for efficient removal of Cs from aquatic environment

In this study, a novel composite material was synthesized by impregnating titania coated silica microsphere functionalized with potassium ferrocyanide in calcium alginate for highly efficient uptake of Cs isotopes from aquatic environment. In order to enhance the stability of silica microsphere, titania was coated over silica microsphere by using sol-gel process. To enhance the exchange capacity of titania coated silica microsphere for Cs, it was functionalized with potassium ferrocyanide. The whole assembly was impregnated in calcium alginate in order to remove the 134+137Cs from potable water without altering drinking water quality parameters. Experiments were conducted by spiking the groundwater and seawater in the concentration range of 1000–50,000BqL−1. Removal efficiency of more than 99% and 97% were observed in case fresh water and marine environment respectively. Sorption capacity of the material was evaluated by using stable Cs. Maximum sorption of Cs was seen at the pH range 7.5–8.5 and the equilibrium time required for the removal of Cs was 24h. Kinetic models and adsorption isotherm equations (Langmuir & Freundlich) were used to fit the experiment data for describing the sorption process. The maximum sorption capacity of the beads is 23.55mgg−1 in case of stable Cs and the sorption follows the Langmuir isotherm. From the kinetic study it was observed that the reaction is following the pseudo first order kinetic equation.

Preparation of 15N-labeled Potassium Ferrocyanide for Tracer Studies

Isotopic labels are widely used to trace the fate and cycling of common environmental contaminants. Many of the labeled materials are not available commercially and, depending on the complexity of the substance, the label and the enrichment level, custom syntheses are costly. A simple, straightforward, and cost effective method for the preparation of a highly enriched, 15N-labeled potassium ferrocyanide (K4[Fe(C15N)6]*3H2O) has been developed to meet the requirements of related tracer experiments and minimize their costs. In this case, the 15N label was used to quantify iron cyanide detoxification (biodegradation and/or transformation) within soil-plant-systems. 15N-labeled potassium cyanide (KC15N) and a ferrous iron salt have been used for the synthesis. Extensive qualitative and quantitative analyses showed a product, entirely identical in its functional and elemental components to commercial non-labeled K4[Fe(CN)6]*3H2O and in its 15N enrichment to the KC15N used for its synthesis. To investigate their behavior and fate in various environmental compartments, other labeled iron or metal cyanide complexes might be synthesized in analogous manner.

Electrophilic fluorination of α-Fe2O3 nanostructures and influence on magnetic properties

Dendritic nanostructures of fluorinated α-Fe2O3 are synthesized using Potassium Ferrocyanide along with Selectfluor™ (F-TEDA), HF, TBABF4, NaF and NH4F as Fe and F precursors respectively in an in-situ hydrothermal process. The choice of sources is based on the nature of fluorine; F-TEDA uniquely acts as a source for electrophilic fluorine while others are nucleophilic in nature. The effect of fluorination on α-Fe2O3 nanostructures is examined from the interplay between (110) and (104) growth direction and crystallite size by X-Ray diffraction analysis and the amount of fluorination is observed by elemental analysis. A significant change in the magnetic property of α-Fe2O3 is observed for different concentrations of F-TEDA. Pristine α-Fe2O3 undergoes an antiferromagnetic to ferromagnetic transition with saturation magnetization value of ~13emu/g and coercivity of 109.8Oe. However, α-Fe2O3 nanostructures prepared with HF, NH4F, TBABF4 and NaF in absence of fluorination remain antiferromagnetic despite of changes in preferred orientation and crystallite size. The interesting magnetic properties arising from F-TEDA is attributed to surface fluorination that results in uncompensated surface spins.