Ferric Ions In Aqueous Solution Research Articles

Using flow-through reactor to enhance ferric ions electrochemical regeneration in electro-fenton for wastewater treatment

Electrochemical regeneration of ferric ions catches more and more attention since it could decrease iron sludge to avoid the sludge problem while it could simultaneously obtain similar robust removal efficiency to refractory organic contaminants in wastewater treatment as the normal Fenton agent method. However, the electrochemical regeneration of ferric ions in aqueous solution was very slow. In this paper, the mass transfer limit of ferric ions in electro-Fenton reaction was evaluated. Koutecky-Levich equation reveals an extremely low diffusion coefficient (D0) value of ferric ions since its complex coordination of [Fe(HO)x(H2O)6-x]3-x. The D0 value was only 2.70 × 10−6 cm2·s−1. Flow-through reactor was therefore introduced in which the ferric ions was designed to penetrate through the 73.1 μm porous holes in the graphite fiber electrode. The μm-scaled confinement of ferric ions diffusion inside the holes was proved to successfully enhance the reduction current of ferric ions by more than 200 % since the diffusion distance of the ferric ions was significantly decreased in the flow-through reactor. However, besides the benefit of the flow-through reactor, the ferric ions reduction electro-Fenton (FeRR electro-Fenton) in flow-through still faces both the pH limit and H2O2 decomposition problems. Hydrogen evolution reaction (HER) could also cause the decrease of pH which exceeded the optimal pH window for Fenton and therefore destroyed the electro-Fenton reaction consequently although the electrochemical reaction of FeRR was 770 mV prior to HER reaction. The regeneration of Fe (II) process simultaneous destruction of H2O2 since H2O2 e-reduction was 120 mV prior to FeRR reaction, which resulted in only very low H2O2 concentration suitable for FeRR electro-Fenton. Even using stepwise addition of H2O2 in electro-Fenton, the decomposition of H2O2 still could not be avoided. Although the decomposition of H2O2 quite limited the application of FeRR electro-Fenton in real application, FeRR electro-Fenton still supports the enhancement removal efficiency of the refractory organic contaminants under low organic contaminants application.

Construction of an ultra-small hydrazone-linked covalent organic polymer for selective fluorescent detection of ferric ion in aqueous solution

A novel ultra-small hydrazone-linked covalent organic polymer (UHCOP) was synthesized based on the Schiff-base reaction between 2,4,6-trihydroxy-1,3,5-benzenetricarbaldehyde and 1,4-benzenedicarbohydrazide at room temperature and utilized as a sensitive fluorescent sensor for rapid (<2 min) and selective detection of Fe3+ in aqueous solution. The prepared UHCOP displayed ultra-small size with the diameter of 7.98 ± 0.97 nm and gave a stable fluorescent emission at 510 nm. UHCOP exhibited good sensitivity and highly selectivity towards Fe3+. The coordination interaction between UHCOP and Fe3+ resulted in the obviously aggregation-caused quenching response of UHCOP. The linear range was from 5.0 μM to 1.4 mM (R2 = 0.999) with the detection limit of 2.5 μM. Finally, UHCOP has been successfully applied in the detection of Fe3+ in real water samples, proving the fabricated UHCOP is promising as a sensitive fluorescent sensor for selective detection of Fe3+ in aqueous solution.

Highly Fluorescent Carbon Dots as a Potential Fluorescence Probe for Selective Sensing of Ferric Ions in Aqueous Solution

This paper’s emphasis is on the development of a fluorescent chemosensor for Fe3+ ions in an aqueous solution, using hydrophilic carbon dots (O-CDs). A simple, cost-effective, and environmentally friendly one-step hydrothermal synthesis method was used to synthesize fluorescent hydrophilic O-CDs from Oxalis corniculata (Family; Oxalidaceae). The graphitic structure and size distribution of the O-CDs was verified by X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy studies. The resulting O-CDs had a near-spherical shape and an adequate degree of graphitization at the core, with an average diameter of 4.5 nm. X-ray photoelectron and Fourier transform infrared spectroscopy methods revealed the presence of several hydrophilic groups (carbonyl, amine, carboxyl, and hydroxyl, along with nitrogen and oxygen-rich molecules) on the surface of O-CDs. The synthesized hydrophilic O-CDs with excitation wavelength-dependent emission fluorescence characteristics showed a high quantum yield of about 20%. Besides this, the hydrophilic O-CDs exhibited a bright and controllable fluorescence with prolonged stability and photo-stability. These fluorescent hydrophilic O-CDs were used as a nanoprobe for the fluorometric identification of Fe3+ ions in an aqueous solution, with high sensitivity and selectivity. By quenching the blue emission fluorescence of this nanosensor, a highly sensitive Fe3+ ion in the range of 10–50 µM with a minimum detection limit of 0.73 µM was achieved. In addition, the developed nanosensor can be used to sense intracellular Fe3+ ions with high biocompatibility and cellular imaging capacity, and it has a lot of potential in biomedical applications.

An In-situ Brine Solution in Salt-cavern Supported Redox-flow Battery Using Iron/Organic Materials

Abstract Salt cavern redox flow batteries with a large salt-cavern storing electrolyte are a promising large-scale energy storage technology. Here a low-cost iron/organic redox material system was proposed to explore salt cavern redox flow batteries. To avoid the formation of ferric hydroxide, ligand threonine was used to enhance the stability of the ferric ion in aqueous solution. Paired with a two electron viologen catholyte and saturated brine solution as supporting electrolyte, the battery delivered a high battery efficiency and cycling stability, 99% CE, 80% EE, and an average 99.5% capacity retention per cycle. The impressive battery performance provides a promising strategy for developing large-scale salt-cavern redox flow batteries.

A Recyclable Optical Fiber Sensor Based on Fluorescent Carbon Dots for the Determination of Ferric Ion Concentrations

A new recyclable fiber optic sensor with a carbon dot/cellulose acetate (CA)-sensitive membrane, in which carbon dots prepared by a hydrothermal method were embedded in the CA film matrix, was successfully used for ferric ion detection. The fluorescent carbon dots immobilized in a sensitive CA membrane are effectively quenched by ferric ion in aqueous solution, and the linear relationship between the fluorescent response of the carbon dots and the Fe3+ concentration was described by the Stern–Volmer equation. A lock-in amplifier was used for detecting the Fe3+ concentration in this recyclable fiber optic sensor based on phase-modulation fluorometry. A linear calibration was obtained in the range from 0.1 to 1.0 mM with a detection limit of 0.03 mM (S/N = 3). This carbon dot/CA sensitive membrane can be recycled and used for ferric ion detection with a good linear calibration.

Manganese-doped carbon quantum dots for fluorometric and magnetic resonance (dual mode) bioimaging and biosensing.

Manganese-doped carbon quantum dots (MnCQDs) were prepared through one-step hydrothermal method using citric acid and manganese tetraphenyl porphyrin as carbon sources in aqueous media. The structure of MnCQDs was confirmed by TEM, XRD, and XPS.The MnCQDs display a typical excitation-dependent emission behavior and exhibit bright green luminescence (with a peak at 482nm) under UV irradiation (365nm) and a fluorescence quantum yield of 13%. The MnCQDs can be used as a fluorescent probe for ferric ion in aqueous solution with a 220nM detection limit. The MTT assay demonstrated the low cytotoxicity of MnCQDs towards HeLa cells. Due to the excitation-dependent emission properties, MnCQDs can be used as a multi-color (blue, green, and red) bioimaging agent in cancer cells and in living zebrafish. The application of MnCQDs as selective biosensing probe for Fe3+ was also realized in cells and zebrafish mode. Because of the existence of paramagnetic ions, MnCQDs demonstratean enhanced magnetic resonance (MR) signal. Thus, the MnCQDs can serve as a positive contrast agent for MR imaging. Graphical abstract Schematic presentation of the preparation of luminescent manganese-doped carbon quantum dots (MnCQDs). MnCQDs showed good magnetic resonance effect and can be used as a fluorescence probe for the detection of Fe3+ in HeLa cells and zebrafish.

Red emitting and highly stable carbon dots with dual response to pH values and ferric ions

The authors describe strongly red-emitting carbon dots (CDs) which were obtained via microwave synthesis using phenylenediamine as the carbon source. The structural and optical properties of the resultant CDs are studied in some detail. The CDs possess (a) longwave emission (peaking at 620nm under 470nm excitation), (b) a quantum yield of ~15%, (c) a size of typically 3.8nm;and (d) good photostability. The CDs have a pH-dependet response that covers the pH5 to 10 range, and their fluorescence is quenched by ferric ions. The CDs can detect ferric ions in aqueous samples in the 0 to 30μM concentration range with a lower detection limit of 15nM. The CDs were also used to image pH values and ferric ions in E. coli bacteria. Graphical abstract The red-emitting carbon dots with high stability are synthesized which show dual response to pH-values and ferric ions in aqueous solution and biological media simultaneously.

Visual determination of ferric ions in aqueous solution based on a high selectivity and sensitivity ratiometric fluorescent nanosensor

A novel ratiometric fluorescent nanosensor for visual sensing of Fe3+ has been developed by integrating yellow-emissive rhodamine derivatives (RhB) onto the surface of silica nanospheres embedded with red CdTe QDs.

Structural, optical and photoconductivity characteristics of pristine FeO·Fe2O3 and NTPI–FeO·Fe2O3 nanocomposite: aggregation induced emission enhancement of fluorescent organic nanoprobe of thiophene appended phenanthrimidazole derivative

In this manuscript we report the successful synthesis of pristine FeO·Fe2O3, 1-(naphthalen-1-yl)-2-(thiophen-2-yl)-1H-phenanthro[9,10-d]imidazole (NTPI), fluorescent organic nanoparticles (FONs) of NTPI and NTPI–FeO·Fe2O3 nanocomposite.

Photocatalytic Degradation of Reactive Red 195 Using Wool-Supported Fe(III) Complex as a Highly Active Heterogeneous Catalyst

In order to obtain a practical Fenton catalyst with low cost, the wool-Fe complex was prepared by a reaction between a wool fiber and ferric chloride at room temperature and characterized using FTIR. This material was then used as a heterogeneous catalyst for the degradation of Reactive Red 195 widely used for the coloration of textiles. Some factors affecting the degradation of Reactive Red 195 such as concentration of Fe3+ions and pH value were investigated. Additionally, the UV-Vis spectra techniques were used to elucidate the catalytic activity of wool-Fe complex under visible light irradiation. The results indicated that wool fibers were able to coordinate with ferric ions in aqueous solution. The higher catalytic activity was obtained at higher concentration of Fe3+in the solution with pH≤6.0.

Phosphate-containing metabolites switch on phosphorescence of ferric ion engineered carbon dots in aqueous solution

Room temperature phosphorescence of carbon dots readily engineered by ferric ions in aqueous solution was developed for a novel “off-to-on” approach for cost-effective estimation of ATP level in human blood plasma.

N-Hydroxyamide-Containing Heterocycles. Part 5.1 Synthesis of Novel Hexadentate Ligands Composed of N-Hydroxy-2(1 H)-pyrazinone, Aliphatic Diamine, and 1,1,1-Tris(carboxyethoxymethyl)ethane, and Properties of Their Ferric Complexes

Novel hexadentate ligands ( 3HOPR nCMe ) containing N-hydroxy-2(1 H)-pyrazinone connected to tricarboxylic acid by an aliphatic diamine through amide bonds were synthesized. UV-vis spectra of the 1:1 molar mixtures of 3HOPR nCMe and ferric ion in aqueous solution and the mole ratio plot strongly supported the formation of intramolecular 1:1 ferne complexes. The relative stability constants (log K 20.6–21.7) of the complexes were affected by the spacer length in a molecule. Further, 3HOPR nCMe showed higher iron removal efficiency toward human transferrin than naturally occurring siderophore, desferrioxamine B.

An investigation of carbonaceous materials reducing ferric ions in aqueous solution

By substituting the ferrous to ferric oxidation for anodic oxygen evolution in an electrowinning cell, it is possible to reduce the cell voltage by about 1 V. However, it is then necessary to reduce the ferric back to ferrous and, depending on the circumstances, acid needs to be cogenerated. Various possible reductants are discussed, and experiments are described on the use of lignite and other carbonaceous materials to reduce the ferric ion. It was found that lignite was able to reduce the ferric ion,in situ in the electrowinning cell, but that the rate of reduction was compatible only with a maximum current density of about 40 Am-2. The efficiency was increased by periodically interrupting the current flow.

Molecular dynamics study of raman scattering and infrared absorption of ferrous and ferric ions in aqueous solution

AbstractUsing a molecular dynamics computer model of water and ion water potentials we have used earlier to study electrolyte structure, we have calculated the infrared absorption and Raman scattering rates of ferrous and ferric ions in aqueous solution. Results for the Raman scattering from the ferric ion in solution are compared with experiments on molten Fe(NO3)3 · 28 H2O. The comparison suggests some new interpretations of the experiments.

FERRIC ION AS PHOTORECEPTOR OF PHOTO‐ PHOBOTAXIS IN NON‐PIGMENTED RHODOSPIRILLUM RUBRUM

Abstract— Rhodospirillum rubrum cultivated aerobically and containing no detectable bacteriochloro‐phyll assembled in their phobotactic response into a spot of blue and near UV light. The shape of the action spectrum for the phenomenon was similar to that of the absorption spectrum of ferric ion in aqueous solution. The photophobotactic response was not observed in media containing no ferric ion. Increasing concentration of the ion in the media resulted in an increasing degree of their photophobotactic response. Ferrous ion could not be substituted for ferric ion unless its autooxidation in medium was allowed.In addition to ferric ion, existence of appropriate anion, by which photoreduction of ferric ion took place efficiently, was necessary to induce an appreciable photophobotactic response. This suggested that the apparent photophobotaxis was, strictly speaking, chemophobotaxis induced by a photochemical product of ferric complex in medium.

Ferrous and Ferric Complexes with Pyridine 2-Aldoxime

PYRIDINE 2-ALDOXIME forms well-defined coloured complexes with ferrous and with ferric ions in aqueous solution. The ferrous complex is violet-red in alkaline solution (with an absorption maximum at 530 mμ), reddish-orange in slightly acidic solution (with a maximum at 515 mμ), and golden-yellow below pH. 3 (with a maximum at 475 mμ). The ferric complex is reddish-brown in alkaline, neutral and slightly acidic solution (with no absorption maxima in the visible), and yellow in more acidic solution. All the colour changes are reversible.

Photoinitiated Oxidation of Benzoic Acid by Ferric Ions in Aqueous Solution1

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoinitiated Oxidation of Benzoic Acid by Ferric Ions in Aqueous Solution1Jerome Saldick and Augustine O. AllenCite this: J. Am. Chem. Soc. 1955, 77, 5, 1388–1390Publication Date (Print):March 1, 1955Publication History Published online1 May 2002Published inissue 1 March 1955https://doi.org/10.1021/ja01610a101RIGHTS & PERMISSIONSArticle Views36Altmetric-Citations5LEARN 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 (321 KB) Get e-Alerts Get e-Alerts

Reduction of Ferric Ion in Aqueous Solution by γ-Radiation

Reduction of Ferric Ion in Aqueous Solution by γ-Radiation