Iron Cyanide Complexes Research Articles

Lithium intercalation behavior into iron cyanide complex as positive electrode of lithium secondary battery

Abstract Lithium intercalation of iron cyanide Prussian blue, Fe 4 [Fe(CN) 6 ] 3 · x H 2 O, in an aprotic media was examined in regard to the water content inside the lattice. Prussian blue showed reversible lithium intercalation potential around 3 V vs. Li, which corresponds to a redox of iron ions. Two types of water molecules were contained in the structure, one of which called zeolitic water has little effect on lithium intercalation and the theoretical capacity was always observed regardless of its amount. Other coordinating water molecules surrounding Fe 3+ ions were necessary for the lithium intercalation and their removal by drying beyond 200°C led to a significant capacity decrease.

Behaviour of cyanides in soil and groundwater: A review

Most people associate the word cyanide with an extremely dangerous and fast-acting poison. However, there are several cyanide species, of varying toxicity, depending on the source to cyanide contamination. The most important cyanide compounds, as well as the most important sources of cyanide contamination in soils and groundwater are discussed. Toxicological and analytical aspects of cyanide containing compounds are briefly touched. The behaviour of cyanide compounds in soil and groundwater is governed by many interacting chemical and microbial processes. Redox conditions and pH are of importance for the leaching and degradation of iron cyanide complexes. Free cyanide is degraded under both aerobic and anaerobic conditions, while documentation of the degradability of iron cyanide complexes only exists under aerobic conditions. The risk associated to the cyanide contained in the different types of sources is evaluated. At gas work sites, where cyanide is mainly present as iron cyanide complexes, the risk for effects on humans from exposure to cyanide compounds seems to be of minor relevance.

Photochemical Destruction of Cyanide in Landfill Leachate

The Allen Park Clay Mine Landfill, owned by Ford, produces a leachate that occasionally contains cyanide at levels marginally below the discharge limit. The form of the cyanide in the leachate was found to be iron-cyanide complexes that resist oxidation by a conventional treatment method, alkaline oxidation. Furthermore, the leachate also was found to contain a relatively large amount of organics (>1,000 mg/L of chemical oxygen demand), which would exert additional demand for oxidizing agents (e.g., chlorine). A study was performed to determine what treatment technology could be employed in the event treatment becomes necessary because of potential changes in the leachate characteristics and/or discharge limits. In this study, among several chemical oxidation methods, ultraviolet (UV) irradiation with or without ozone was investigated as a treatment option. The following are the primary findings: (1) UV irradiation alone was effective for removing the iron-cyanide complex in both the leachate and the clea...

Preparation, reduction, and CO chemisorption properties of cyanide-derived Cu xFe/Al 2O 3 catalysts

A series of copper–iron catalysts with Cu-to-Fe proportions of 1.0, 1.5, and 2.0 has been prepared by the precipitation of three different copper–iron cyanide complexes, viz. Cu 2Fe(CN) 6, Cu 3[Fe(CN) 6] 2 and CuFe(CN) 5NO, onto a γ-Al 2O 3 support. Oxidative decomposition of these stoichiometric heteronuclear cyanide complexes resulted in the formation of particles of uniform Cu-to-Fe ratio, made up of intimately mixed CuO and Fe 2O 3 crystallites. The reduction of the oxidic precursors was studied by means of magnetization measurements and Mössbauer spectroscopy. The presence of Cu facilitates the reduction of the iron oxide. The distribution of the Cu and Fe atoms in the bimetallic particles appeared to be strongly dependent on the applied reduction procedure. Slow reduction prevents excessive phase separation. Exposure of the reduced catalysts to carbon monoxide results in a rapid segregation of Fe to the particle surface. Infrared spectroscopy indicates the presence of several types of linearly and bridged-bonded CO species on the bimetallic surface. Reversibly adsorbed CO on Cu-like sites decreases the apparent intensity of the absorption band due to irreversibly adsorbed CO on Fe-like sites. Experiments with isotopically labeled C 18O suggest that the CO on Fe-like sites is mobile and can be exchanged with CO bonded to adjacent Cu-like sites.

Cyanides in a soil of a former coking plant site

AbstractSoils of former coking plant sites are frequently contaminated with cyanide, which mainly occurs as the pigment Berlin blue, FeIII4 [FeIICN)6]3, and soluble iron cyanide complexes, Fe(CN)63‐/4−. Berlin blue is only slightly soluble under acidic conditions.The cyanide mobility in a strongly acid soil (pH about 3) of such a site was studied by assessing the distribution of cyanides in the soil and sediment and by conducting batch experiments at different pH levels.The soil is based on a disposal layer (0–32 cm) overlying sandy loess (32–145 cm) overlying glaciofluvial sand (145–250 cm) overlying marlstone (250–500 cm). Highest cyanide concentrations were found in the disposal layer (62–2865 mg CN− kg−1), medium concentrations in the sandy loess (16–29 mg CN− kg−1), concentrations of about 100 mg CN− kg−1 in the glaciofluvial sand and lowest concentrations in the marlstone (0.22–0.49 mg CN−1 kg−1). The surfaces of macropores, which occur in the sandy loess and finish in the glaciofluvial sand, are dark‐blue dyed and have much higher cyanide concentrations than the surrounding bulk soil. Thus, the accumulation of cyanides in the sand layer may partly be the result of macropore flow.Batch experiments show a strong pH dependence of the solubility of cyanide in the soil as well as of Berlin blue which was found by Mössbauer spectroscopy to be the dominating or sole iron cyanide.The time necessary to transport the cyanides solely as hexacyanoferrate into the undisturbed horizons is estimated to 1000 yr. However, because Berlin blue is known to form colloids, we discuss the possibility of cyanide transport as colloid not requiring dissolution and reprecipitation. We postulate that colloidal Berlin blue transported by macropore flow is responsible for the high mobility of cyanides in this acid soil.

Photoinduced water oxidation by polymeric iron cyanide complex

AbstractIt was found that photoelectrochemical water oxidation takes place at a polynuclear iron‐cyanide complex‐coated electrode called Berlin Brown (BB; Fe4III[FeIII(CN)6]33 3X). The electrode‐coated BB showed electrocatalytic activity for water oxidation to produce O2 not only in the dark but also under illumination to result in photoinduced water oxidation. The amount of the photoelectrochemically produced O2 increased with the thickness of the BB film, indicating that the BB works as a bulk catalyst.

Prussian White as a highly active molecular catalyst for proton reduction

Electrocatalytic H + reduction was found with the polynuclear iron-cyanide complex called Prussian White (PW, K 4Fe II 4[Fe II(CN) 6] 3) coated on a Pt electrode. The PW-coated Pt produced much larger amounts of H 2 than a bare electrode even at the theoretical potential of H + H 2 . Its electrocatalytic activity exceeded the conventional Pt catalyst.

Toxicity of cyanide and cyanide complexes to the marine diatom Nitzschia closterium

The effect of sodium cyanide (NaCN), iron-cyanide complexes and a blast furnace effluent on the growth of the unicellular marine diatom Nitzschia closterium was investigated. Due to the volatile nature of HCN, the free and total cyanide concentrations in all test solutions were monitored daily to ensure that average daily losses of free cyanide did not exceed 5%. The iron-cyanide complexes were less toxic than the NaCN, with 72-h EC 50 values of 57, 127 and 275 μg total-CN litre −1 for NaCN, K 3Fe(CN) 6 and K 4Fe(CN) 6, respectively. The estimated lowest observed effect concentration (LOEC) for NaCN was 10 μg litre −1. The toxicity of the cyanide complexes was largely due to free cyanide (HCN + CN −) with possible additional toxicity caused by dissociation of the complexes at the algal cell membrane. The toxicity of an effluent from a blast furnace drawdown episode also correlated well with the toxicity of free cyanide.

Toxicity of cyanide, iron-cyanide complexes, and a blast furnace effluent to larvae of the doughboy scallop, Chlamys asperrimus.

Toxicity of cyanide, iron-cyanide complexes, and a blast furnace effluent to larvae of the doughboy scallop, Chlamys asperrimus.

Adsorption Characteristics of Iron–Cyanide Complex on γ-Al 2O 3

The adsorption behavior of ferrocyanide and ferricyanide toward aluminum oxide with a 0.01 MNaClO 4background electrolyte at 25°C was investigated. Results obtained from different pH values demonstrated that the adsorption of these complex ions could be described by a modified Langmuir isotherm in the concentration range 0.5 × 10 −4to 4 × 10 −4 M.This modified Langmuir isotherm developed here could accurately predict the equilibrium partition between solid and liquid phases while taking proton competition into account. Also, the apparent equilibrium constant ( K app) derived from the Langmuir equation for ferrocyanide or ferricyanide adsorption on aluminum oxide was compared with the intrinsic constant ( K int) calculated by triple-layer model simulation. This comparison revealed a strong correlation between the apparent equilibrium constant and the intrinsic constant. Moreover, in comparing K appwith K int, we can infer that the adsorption of either ferrocyanide or ferricyanide complexes onto aluminum oxide is achieved through outer-sphere complexation.

Transport of complexed cyanide in soil

Contamination of soil with cyanide, generally in the form of iron cyanide complexes [Fe(CN) 6 3− and Fe(CN) 6 4−], is commonly found at several types of industrial sites. The risks for human health or the environment posed by such sites are largely determined by the chemical behaviour and transport of complexed cyanide in soil. In acidic soil this behaviour is probably dominated by equilibrium with Prussian blue, Fe 4(Fe(CN) 6) 3(s), which is sparingly soluble under acidic conditions and limits dissolved cyanide concentrations and mobility. However, at pH levels higher than about 7 the solubility of this precipitate is extremely high, which allows cyanide to be very mobile under such conditions. Nevertheless, according to field observations, Prussian blue appears to persist for decades in alkaline soils. In this paper multicomponent transport calculations, including equilibrium with Prussian blue, iron hydroxide and relevant redox reactions, are compared with the situation as observed in two contaminated soil profiles. In case of an acidic soil, there appears to be good agreement between the calculations and the field situation. Here the mobility of cyanide is mainly regulated by the pH and redox potential and is relatively low. In case of an alkaline soil, precipitation of Prussian blue will not take place and cyanide will be very mobile once leached from the initial waste material. In this case the dissolution rate of Prussian blue is the process which determines cyanide concentrations in the groundwater. The calculations show that this dissolution rate is determined by the acid neutralizing capacity of the solution infiltrating in the waste material. The buffer capacity depends on the soil composition and can easily be so low that complete dissolution of Prussian blue may take decades. This very likely explains the persistence of this material in alkaline soils.

Differential effects of nitric oxide gas and nitric oxide donors on depolarization-induced release of [ 3H]norepinephrine from rat hippocampal slices

The NO-generating compounds sodium nitroprusside (NP), nitroglycerin (NTG), and isosorbide dinitrate (ISDN) all significantly inhibited N- methyl- d-aspartate (NMDA)-stimulated release of tritiated norepinephrine ([ 3H]NA) from preloaded hippocampal slices of adult male Sprague-Dawley rats with IC 50 's of 114 μM, 1.2 mM, and 1.7 mM respectively. NTG and ISDN also inhibited KCl-stimulated release, while NP had no significant effect on KCl-stimulated release. Although these results suggest that the inhibitory effects of these compounds were mediated by release of NO, NTG and ISDN did not generate detectable levels of NO, and iron-cyanide complexes similar in structure to NP but lacking NO also inhibited release. In contrast, both S- nitroso-N- acetyl- d , l-penicillamine (SNAP) and authentic NO gas significantly enhanced NMDA-stimulated release of [ 3H]NA (EC 50's: 331 and 3.4 μ M respectively). This enhancement was not selective for NMDA-stimulated release, since both SNAP and NO potentiated KCl-stimulated release as well. In addition, NO gas significantly enhanced NMDA-stimulated release of tritiated dopamine ([ 3H]DA) from striatal slices and [ 3H]NA from cortical and cerebellar slices. Analogs of cyclic guanosine monophosphate (cGMP) had no significant effect on NMDA-stimulated transmitter release, suggesting that the observed increase in release is via a cGMP-independent mechanism. While exogenous NO enhanced both NMDA- and KCl-stimulated neurotransmitter release, it appears that endogenous NO does not play a role in this depolarization-induced release since NO synthase inhibitors did not significantly reduce NMDA-stimulated [ 3H]NA release. The possibility remains that endogenous NO could modulate neurotransmitter release in other circumstances.

Treatment of concentrated cyanide wastewater

The effluent of Tufftride Process, a soft nitriding process for ironrelated material, contains concentrated iron cyanide complex. Due to the nature of the effluent, a treatment process employing conventional technology may become a complex one. For this reason, a simple advanced system with new technology has been hoped for.Since 1991, Water Reuse Promotion Center (WRPC), collaborating with Osaka Gas Co., Ltd. (OGC) and Nihon Parkerizing Co., Ltd (NPC), has been working to develop a new process for treating concentrated cyanide wastewater using OGC catalytic wet oxidation (CWO) process. Through the operation at NPC Sendai plant, it has been confirmed that the process is technically feasible and economically acceptable.

Solubility of Cyanide in Contaminated Soils

AbstractAt more than 200 sites in the Netherlands, the soil is contaminated with cyanide as a result of industrial activities. The mobility of cyanide, which mainly occurs in the form of iron cyanide complexes [Fe(CN)63− + Fe(CN)64−], plays an important role in predicting the possible hazards for the environment and human health. Cyanide mobility was investigated by assessing data on cyanide concentrations in groundwater at contaminated sites, and by examination of three contaminated soils. High cyanide concentrations were found in the groundwater at sites with alkaline soils (pH ca. 7.5), whereas much lower concentrations were found in the groundwater with acidic soils (pH ca. 4). This agreed with the assumption that the behavior of cyanide in these contaminated soils is largely governed by the solubility of Prussian blue [Fe4(Fe(CN)6)3(s)], which is relatively insoluble under acidic conditions. In the acidic soils, the concentrations in the soil water appeared to be close to equilibrium with Prussian blue. In alkaline soils this precipitate is extremely soluble. The presence of this material here was possibly the result of slow dissolution kinetics. Precipitation of Prussian blue in acidic soils does not prevent dissolved iron cyanide concentrations from exceeding Dutch soil quality standards.

Optical properties of Prussian-Blue-modified gold and platinum single-crystal electrodes

Prussian Blue (PB) is a polynuclear mixed-valent iron cyanide complex which is zeolitic in nature and has a face-centred cubic structure with a lattice constant of about 10 A [l]. PB-modified electrode surfaces have been the subject of intense study in recent years because of their potential for application in areas such as electrochromism [2,3], electrocatalysis [4,5], photosensing devices [61, charge storage [7,8], ion-selective sensors [9] and semiconducting films [lo-121. Modification of electrodes such as polycrystalline Pt, Au and glassy carbon (GC) with thin PB films using different chemical and electrochemical procedures have been described in the literature [2,7,8,12]. A cyclic polarization procedure for the modification of GC with PB in a neutral medium has been reported in earlier communications [lO,ll]. The PB overlayer has been characterized by in-situ Mijssbauer spectroscopy [13] in order to identify the low spin Fen and the high spin Fe”’ species present in the PB skeleton. In-situ optical absorption spectra on PB-modified SnO, have also been reported in the 400-800 nm region [14]. However, it is desirable to characterize the optical properties of the material over as wide a wavelength range as possible. In the following we present the results of an optical study of PB-modified single-crystal Au and Pt electrodes with special emphasis on the (111) faces of Au and Pt, where the surface redox processes are seen particularly clearly.

Metal ion capillary zone electrophoresis with direct UV detection: Separation of metal cyanide complexes

AbstractMixtures of cyanide complexes of iron(III), copper(I), iron(II), nickel(II), chromium(III), mercury(II), palladium(II), silver(I), cadmium(II), zinc(II), cobalt(II), and cobalt(III) have been separated by capillary zone electrophoresis using a fused silica capillary and 20 mM phosphate buffers containing 1–2 mM sodium cyanide. The complexes were detected by direct UV absorpticn at 214 nm; detection limits are in the mid ppb range for all metals except cadmium and zinc. The different detectability of various metal cyanide complexes enables the application of the method to the analysis of complex matrices such as cyanide plating bath solutions.

Chemical stability and decomposition rate of iron cyanide complexes in soil solutions

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical stability and decomposition rate of iron cyanide complexes in soil solutionsJohannes C. L. Meeussen, Meindert G. Keizer, and Frans A. M. De HaanCite this: Environ. Sci. Technol. 1992, 26, 3, 511–516Publication Date (Print):March 1, 1992Publication History Published online1 May 2002Published inissue 1 March 1992https://doi.org/10.1021/es00027a010RIGHTS & PERMISSIONSArticle Views904Altmetric-Citations118LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (763 KB) Get e-Alerts Get e-Alerts

Photochargeable multilayer membrane device composed of CdS film and prussian blue battery

Photoenergy conversion and storage are attracting attention not only in solar energy utilization but also in photodevices which are important for the future socalled photonics (photoelectronics). Photoinduced charge separation and the following accumulation of the separated charges are typical processes in photoenergy/information conversion and storage. These processes are generally carried out in different systems or phases respectively to result in a whole achievement. If they are combined to realize in one device, it must be of much value for the development of photodevices. Such a device is capable of photocharge and dark-discharge, and would open a new field in photoenergy and information conversion/storage. Some systems for photocharge and dark-discharge have been reported that are composed of liquidjunction semiconductor and redox electrolyte present in solution[l-51. A new concept is now proposed to realize photocharge and dark-discharge by a multifunctional solid state device, which must be of great use for practical application. The present authors have designed a multilayer membrane device for photocharge and dark-discharge so that each layer bears a function such as photoinduced charge separation, accumulation of positive/negative charges, separation of reactants. As for the membrane materials, polymer is most suited for practical use[6]. As a charge storage material, Prussian Blue (PB) which is a high molecular and polynuclear mixedvalent iron cyanide complex was chosen in the present paper. Electrochemical behavior of PB has been well characterized by Neff and Itaya et aI.[7-91. This complex, whose composition is represented by Fe:’ [Fe”(CN),]:-, has three kinds of reversible redox states, so that it can store both positive and negative charges. PB batteries were reported by NefllO], Kanekorll, 123, and Honda et al.[13] in which two PB films were utilized for an anode and a cathode. A multilayer PB polymer battery (PB/Nafion/PB) has been fabricated, and its reaction characteristics have been studied electrochemically and spectrophotometrically by the present authors[12]. Photoreaction of PB film coated on TiO, has been studied in aqueous electrolyte solution[14], but this system uses only ultraviolet light and dark-discharge has not been reported. In the present paper, a multilayer solid type photochargeable device driven by visible light irradiation will be reported which is composed of n-CdS semiconductor film and trilayered PB battery membranes.

Destruction of Iron-Complexed Cyanide by Alkaline Hydrolysis

Iron-complexed cyanide compounds are found in various industrial wastes, and are resistant to destruction by conventional technologies used to treat cyanide-bearing wastes. This study evaluated hydrolytic destruction of iron-complexed cyanide in leachates from land disposal of spent carbonanceous material used to line aluminum reduction cells. The investigation showed that iron-cyanide complexes may be hydrolyzed under alkaline conditions at elevated temperatures and pressures, e.g. in the range of 165-180 °C and 100-150 psig. The hydrolysis reaction is apparently first-order with respect to total cyanide. The reaction yields stoichiometric amounts of ammonia and formate, and Fe3O4(s). The rate of the reaction is especially temperature dependent, and for the case of spent potlining leachate, the hydrolysis rate may be estimated by an Arrhenius kinetic expression for hydrolysis of simple cyanide. The rate of the hydrolysis reaction for iron-complexed cyanide is compared to that for other metal-cyanide complexes. It is shown that waste composition may affect the hydrolysis rate, and that the instability of certain metal-cyanide complexes with respect to alkaline chlorination does not correlate with instability with respect to alkaline hydrolysis. Alkaline hydrolysis is an appropriate technology for destruction of iron- and other metal-cyanide compounds in wastes at high concentrations.

ChemInform Abstract: EPR Studies of Irradiated Single Crystals of Alkali Halides Doped with Cyanide Complexes of Cobalt, Rhodium, Iridium, Iron, Ruthenium and Osmium. A Review

ChemInform Abstract: EPR Studies of Irradiated Single Crystals of Alkali Halides Doped with Cyanide Complexes of Cobalt, Rhodium, Iridium, Iron, Ruthenium and Osmium. A Review