Ferric Ions In Solution Research Articles

Tune wastepaper to hydrophobic membranes through metal-ion-induced lignocellulose nanofibril crosslinking for oil-water separation

Herein, we proposed a metal-ion-induced surface nano-engineering technology for transforming hydrophilic waste newspaper (WNP) into a hydrophobic material suitable for oil-water separation, without using hydrophobic chemicals/materials. WNPs were swelled in a dilute ferric ion solution (i.e., 50 mM FeCl3) followed by oven-drying to induce the coordination between ferric ions and hydroxyls of lignocellulose nanofibrils of the paper. This resulted in the crosslinking of lignocellulose nanofibrils and converted the hydrophilic WNP to the hydrophobic membrane (HM). The HM exhibited remarkable oil sorption capacity for various oils, up to 3.4 times its weight, and demonstrated good recyclability after undergoing 10 cycles of absorption-desorption-drying. Additionally, HM demonstrated the ability to effectively separate both immiscible oil-water mixtures and surfactant-stabilized water-in-oil emulsions in continuous gravity-driven oil-water separation processes. With the modification method and advantages in oil-water separation, the as-prepared HM exhibits great potential for application in oil spill treatment and environmental remediation.

Influences of Ferric Ions and Fe as a Minor Element in the Lattice on the Floatability of Cassiterite.

In this study, synthetic pure cassiterite and cassiterite doped with two different Fe contents were successfully recrystallized by means of sintering. Their crystal structure and chemical compositions were characterized by X-ray powder diffraction (XRD) as well as scanning electron microscopy (SEM) combined with energy-dispersive X-ray (EDX) analysis. Their floatability was studied by microflotation with a diphosphonic acid surfactant named Lauraphos301 as a collector. Unlike the addition of ferric ions in solution, which strongly depressed the floatability of all of the cassiterite samples, a much higher flotation efficiency of the Fe-doped cassiterite samples was found especially at lower collector concentrations. The cassiterite floatability is proportional to the Fe content in cassiterite at a broad range of pH, and the recovery has the following order: cassiterite with 1417 ppm Fe > cassiterite with 1165 ppm Fe > pure cassiterite. The electrokinetic behavior of the cassiterite samples with and without the collector was studied by electrophoretic measurements and revealed that the chemical interaction dominated the adsorption. With the help of the particle shape analysis, a more angular shape was found for the Fe-doped cassiterite samples. Moreover, without the influence of particle shape, much abundant adsorption of Lauraphos301 was found on the Fe-doped cassiterite samples by AFM topography imaging. The minor amount of Fe in the cassiterite lattice and a more angular shape of the Fe-doped cassiterite samples were believed to enhance floatability collectively. The study reveals that the influence of the chemical composition of the minerals on flotation was almost inextricably bound up with particle morphology and emphasizes the importance of considering both factors and investigating them individually for the flotation study.

High-Strength, Conductive, Antifouling, and Antibacterial Hydrogels for Wearable Strain Sensors.

Conductive hydrogels have shown great potential in the field of flexible strain sensors. However, their application is greatly limited due to the poor antifouling and low mechanical strength. Unfortunately, it is still a challenge to improve these two distinct properties simultaneously. Herein, a hydrogel with high strength, good conductivity, and excellent antifouling and antibacterial properties was prepared through the synergistic effect of physical and chemical cross-linking. First, acrylic acid (AA), acrylamide (AM), and 2-methacryloyloxyethyl phosphorylcholine (MPC) monomers were polymerized in the presence of chitosan chains to form the hydrogel. Then, the prepared hydrogel was immersed in a ferric ion solution to further strengthen the hydrogel through ion coordination. The obtained CS-P(AM-MPC-AA0.2)-Fe0.13+ hydrogel showed outstanding tensile strength (1.03 MPa), excellent stretchability (1075%), good toughness (7.03 MJ/m3), and fatigue resistance. The CS-P(AM-MPC-AA0.2)-Fe0.13+ hydrogel also demonstrated good ion conductivity (0.42 S/m) and excellent antifouling and antibacterial properties. In addition, the strain sensor constructed by the CS-P(AM-MPC-AA0.2)-Fe0.13+ hydrogel showed high sensitivity and good stability. This work presented a facile method to construct a zwitterionic hydrogel with high-strength, conductive, antifouling, and antibacterial properties, which suggested a promising gel platform for flexible wearable sensors.

Combined effect of silver ion and pyrite on AMD formation generated by chalcopyrite bio-dissolution

Chalcopyrite is a crucial contributor causing acid mine drainage (AMD). Silver and pyrite are commonly co-existed with chalcopyrite, and can significantly affect the copper release from chalcopyrite bio-dissolution process. However, the combined effect of them on chalcopyrite bio-dissolution has not been illustrated up to now. To fill this knowledge gap, the combined effect of silver and pyrite on chalcopyrite dissolution with Acidithiobacillus ferrooxidans was investigated in this study. The copper extraction reached the maximum value (62.3 ± 0.1%) with the presence of silver and pyrite, which was 43.8 ± 0.1% higher than the control group (without addition). This suggested more copper ions and acids were released under this circumstance. According to bio-dissolution results, SEM, XRD and XPS analyses, the promotion effect of silver and pyrite on chalcopyrite bio-dissolution was mainly attributed to the increase of ferric ions in solution and the reduction of passivation layer (Sn2−/S0) on chalcopyrite surface. The investigation into the bio-dissolution of chalcopyrite is important for controlling the generation of copper ions and acids. Silver or pyrite bearing chalcopyrite should be carefully treated to avoid the pollution of heavy metal copper and acid in the mining environment.

A three-dimensional nanostructure of NiFe(OH) X nanoparticles/nickel foam as an efficient electrocatalyst for urea oxidation.

Developing high-performance electrocatalysts for urea oxidation reaction (UOR) can not only solve the problem of environmental pollution, but also solve the problem of the energy crisis by producing hydrogen for electrodes. The preparation of porous three-dimensional nanostructures as efficient electrocatalysts has become important work. Here, we developed a novel three-dimensional (3D) nanostructure of NiFe(OH)X nanoparticles/nickel foam with a high active area by a simple electroplating method and a subsequent treatment with ferric ion solution. This structure shows much greater UOR activity than the control sample (Ni/Ni foam) with the potential of 1.395 V (vs. RHE) (with an overpotential of 1.025 V) for driving the current density of 100 mA cm−2 in 1.0 M KOH electrolyte with 0.33 M urea. This work not only provides rapid and large-scale preparation of a three-dimensional nanostructure, but also gives a new way to design and obtain high-performance electrocatalysts.

Effects of soybean curd wastewater on growth and DHA production in Aurantiochytrium sp.

Soybean curd wastewater (SCWW) is a by-product of the compression of protein coagulants performed during production of soybean curd (tofu). In this study, SCWW was used as a low-cost nutrient source for the cultivation of an Aurantiochytrium strain known to produce significant amounts of polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA). Instead of sterilization of the SCWW medium by heating (which promotes the Maillard reaction and production of hydroxymethylfurfural), the SCWW medium was sterilized using peracetic acid (PAA) followed by neutralization with a ferric ion solution. The growth of cells was similar in PAA-sterilized SCWW medium and sterile-filtered or autoclaved M7D20 medium that contained commercial components (glucose, yeast extract, and peptone). Surprisingly, cells grown in PAA-sterilized SCWW medium had more than 4-fold greater production of DHA than cells grown in autoclaved or filtered M7D20 medium.

Insight into performance and mechanism of tea polyphenols and ferric ions on reductive decolorization of malachite green cationic dye under moderate conditions

Dye decolorization is of crucial concern for effectively treating dye wastewater. In this study, rapid and effective decolorization of malachite green cationic dye was achieved by tea polyphenols and ferric ions under moderate conditions. Approximately 96.2% of decolorization efficiency could be obtained within the first 10 min at the initial dye concentration of 50 mg/L. The proposed method can perform excellently in a wide pH range of 5–9 and decolorization kinetics of malachite green under different solution pH were well fitted by the pseudo-second-order model. After the decolorization, only a slight reduction of tea polyphenols was observed, while the strength of peaks assigned to nitrogen-containing groups was significantly weakened, indicating that the N-demethylation reaction might occur during the decolorization process. The nucleophilic attack of deprotonated hydroxyl groups of tea polyphenols was proposed as the decolorization mechanism. The presence of ferric ions at an appropriate dosage could promote the deprotonation process and therefore enhance decolorization efficiency, while excess ferric ions in solution might compete with malachite green dye towards reductive sites on tea polyphenols. The findings from this study provided an economical and environmentally friendly technique for the effective decolorization of dye wastewater.

UV-shielding alginate films crosslinked with Fe3+ containing EDTA

In this study, we fabricated a soft, transparent UV-shielding film (Alg-Fe3+-EDTA) by crosslinking sodium alginate with a ferric ion solution containing EDTA. The obtained films were characterized via SEM, ATR-FTIR, XRD, TG and DTG; the results indicated that the synergistic gelation of ferric alginate and alginic acid existed in Alg-Fe3+-EDTA film. The Alg-Fe3+-EDTA film performance to be optimized under the following conditions: 1.6% Fe3+, 0.8% EDTA, and crosslinking duration of 12 min. The Alg-Fe3+-EDTA film had high visible light transmittance, the UV-C (200–280 nm) and UV-B (280–315 nm) shielding rates were 100%, and the UV-A (315–400 nm) shielding rate was 98.37%; the UPF reached 50+; additionally, the tensile strength and elongation-at-break were 56.85 MPa and 10.45%, respectively, and still have ultraviolet shielding effect under water environments or after strong light irradiation. This work provides an efficient method to improve the optical and mechanical ability of ferric alginate films.

Ferrozine‐Based Assay for Determining Iron Content in Insect Cells

We are optimizing a ferrozine‐based assay to analyze the iron content in Drosophila S2 cells. We hypothesize that putative ferric reductases CG1275 or CG8399 may be involved in reducing iron in the hemolymph and allowing uptake into cells. We have modified a ferrozine‐based assay, in which ferrozine complexes with ferrous ions in solution and forms a stable magenta complex species that can be detected at 562 nm. Using this method with an Ultraspec II spectrophotometer we obtained a limit of detection of 0.30 μg/mL. This method provides a reliable, inexpensive and simple way of analyzing and quantifying the iron content within the S2 cells, allowing us to analyze iron content after RNA interference experiments to knock down CG1275 and CG8399.Support or Funding InformationNSF IOS‐1656407This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effect of Silica on Rice Agromorphological Diversity Under Iron Toxicity Conditions in Lowland Rice of Guinea Conakry

Rice is the second most important cereal in West Africa and is an essential element in the diet of the population. However, iron toxicity is one of the major edaphic constraints in lowland rice cultivation. The large amount of ferrous ions in solution causes an imbalance in nutrients involving a nutritional disorder affecting the growth of crops including rice. The present study conducted in 2014 in Guinea Conakry in the lowlands of the Kilissi Agronomic Research Station aimed to evaluate the effect of silica on reducing of the effect of iron toxicity in rice. Thus, rice varieties were evaluated according to a split plot device with three (3) randomized replications for two factors (rice varieties and silica doses) and three (3) silica treatments (D0 g, D120 g and D240 g). The results showed a significant effect of silica on most agronomic parameters of the rice varieties tested. The D240 g dose gave the best yields of up to 6.9 t/h. Seventeen (17) varieties exhibited good agronomic characteristics of yield, cycle, and weight of 1000 grains. In addition, the study reveals a possibility of reducing the effect of iron toxicity in lowlands in Guinea by the combined use of silica and rice varieties resistant or tolerant to iron. The genetic variability observed with certain tolerant varieties with ferrous toxicity like CK4 could be exploited in our national rice breeding program.

Preparation and Characterization Composites Contain of Magnetic Iron Oxide Nanoparticles with Different Weight Ratios of Dextrin, and Using it to Removal of Heavy Metals from Aqueous Solutions

The iron oxide magnetic nanoparticles (MNPs) have been synthesized by using a co- precipitation method aqueous solution of ferric and ferrous ions in, sodium salt, which is used to controlled The size of the iron-oxide, then coated those nanoparticles with different weight ratio of dextrin. The samples were characterized by x-ray diffractometer (XRD), FTIR spectroscopy, atomic force microscope (AFM) and scanning electron microscope (SEM).The research studied the ability of using coated magnetite with weight ratio of dextrin(1-2) as adsorbents for the removal of heavy metals like lead and chrome from aqueous solution with in variable experimental factors. The data obtained from this study revealed that higher efficiency was observed with lead ion whereas the lower with chrome ion.

The hidden systems in the human brain

Soybean curd wastewater (SCWW) is a by-product of the compression of protein coagulants performed during production of soybean curd (tofu). In this study, SCWW was used as a low-cost nutrient source for the cultivation of an Aurantiochytrium strain known to produce significant amounts of polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA). Instead of sterilization of the SCWW medium by heating (which promotes the Maillard reaction and production of hydroxymethylfurfural), the SCWW medium was sterilized using peracetic acid (PAA) followed by neutralization with a ferric ion solution. The growth of cells was similar in PAA-sterilized SCWW medium and sterile-filtered or autoclaved M7D20 medium that contained commercial components (glucose, yeast extract, and peptone). Surprisingly, cells grown in PAA-sterilized SCWW medium had more than 4-fold greater production of DHA than cells grown in autoclaved or filtered M7D20 medium.

Homogeneous photocatalytic Fe3+/Fe2+ redox cycle for simultaneous Cr(VI) reduction and organic pollutant oxidation: Roles of hydroxyl radical and degradation intermediates.

The sustained oxidation of aqueous organic pollutants using hydroxyl radicals (HO) generated in the UV-irradiated solution of ferric ions was investigated in the presence of Cr(VI). The synergistic effect of simultaneous 4-chlorophenol (4-CP) oxidation and Cr(VI) reduction is explained in terms of the various roles of OH radical, degradation intermediates, and Fe3+/Fe2+ redox cycle. The photolysis of FeIII(OH)2+ generates OH radical which degrades the organic substrate. The reduction of Cr(VI) was inhibited by the OH radical-induced re-oxidation of Cr(III) in the absence of 4-CP. The complete removal of Cr(VI) was achieved only in the presence of phenolic substrates which not only reacts with OH radical (hence inhibiting the reoxidation of Cr(III)) but also generates reducing intermediates which effectively reduce Cr(VI). Fe2+ also converted Cr(VI) to Cr(III) with regenerating Fe3+, which makes the overall process photocatalytic. The photocatalytic activity for the simultaneous removal of 4-CP and Cr(VI) was largely maintained up to five cycles. Such simultaneous and synergic photoactivity was also observed for other phenolic compounds (4-bromophenol, 4-nitrophenol, phenol). The simultaneous and synergic removal of phenolic compounds and Cr(VI) can be enabled through the redox couple of Fe3+/Fe2+ working as a homogeneous photocatalyst.

Investigating the Effect of Ferrous Ions on the Anomalous Hydrogen Evolution on Magnesium in Acidic Ferrous Chloride Solution

Electrochemical testing, hydrogen collection and on-line inductively coupled plasma mass spectroscopy are used to assess the dissolution of high purity magnesium and the attendant hydrogen evolved in solutions containing ferrous ions. It was revealed that ferrous ions in solution had a minimal effect on the hydrogen evolved upon anodically polarized magnesium. The results show that deposition of ferrous ions could not account for enhanced hydrogen evolution during anodic polarization of magnesium. Further analysis of the results obtained under the testing conditions in this study show that the anomalous hydrogen evolution exhibited by dissolving Mg was associated with the regions of anodic dissolution.

Effect of substituted hydroxyl groups in the changes of solution turbidity in the oxidation of aromatic contaminants.

This paper deals with the changes of turbidity that are generated in aqueous solutions of phenol when they are oxidized by using different Fenton technologies. Results revealed that if the Fenton reaction was promoted with UV light, the turbidity that was generated in the water doubled. Alternatively, the use of ultrasonic waves produced an increase in turbidity which initially proceeded slowly, reaching intensities eight times higher than in the conventional Fenton treatment. As well, the turbidity showed a high dependence on pH. It is therefore essential to control acidity throughout the reaction. The maximum turbidity was generated when operating at pH=2.0, and it slowly decreased with increasing to a value of pH=3.0, at which the turbidity was the lowest. This result was a consequence of the presence of ferric ions in solution. At pH values greater than 3.5, the turbidity increased almost linearly until at pH=5.0 reached its maximum intensity. In this range, ferrous ions may generate an additional contribution of radicals that promote the degradation of the phenol species that produce turbidity. Turbidity was enhanced at ratios R=4.0mol H2O2/mol C6H6O. This value corresponds to the stoichiometric ratio that leads to the production of turbidity-precursor species. Therefore, muconic acid would be a species that generate high turbidity in solution according to its isomerism. Also, the results revealed that the turbidity is not a parameter to which species contribute additively since interactions may occur among species that would enhance their individual contributions to it. Analyzing the oxidation of phenol degradation intermediates, the results showed that meta-substituted compounds (resorcinol) generate high turbidity in the wastewater. The presence of polar molecules, such as muconic acid, would provide the structural features that are necessary for resorcinol to act as a clip between two carboxylic groups, thus establishing directional hydrogen bonds that would generate an adduct in the 2:2 ratio. In addition, some similarity is observed between the turbidity and the presence of dihydroxybenzoquinone. This molecule has a structure that could establish hydrogen bond links with the carboxylic groups in 1:2 ratio. Such supramolecular structures would possess high molecular weight and robustness that would hinder the passage of light through the water, generating high turbidity.

Aerosol synthesis of Graphene-Fe3O4 hollow hybrid microspheres for heterogeneous Fenton and electro-Fenton reaction

Fenton reaction has been widely used to treat wastewater containing dyes, herbicides, antibiotics, and landfill leachate because of its convenience and strong oxidation ability. The rational design and preparation of efficient and stable Fenton catalysts have been the focus of research. In this study, graphene-magnetite hollow hybrid microspheres were synthesized by a facile aerosolized spray drying route utilizing ferric ion and graphene oxide (GO) solution as the precursor. The results showed that uniform hybrid microspheres with possess hollow structure, high saturation magnetization and high Fenton catalytic activity with 30wt% graphene (30G-FeO) as catalyst. By the electrochemical analysis, a two-electron dominated process has been demonstrated to explain higher electrocatalytic activity. Accordingly, a novel electro-Fenton (EF) system with the 30G-FeO cathode was established working at acidic condition. The 30G-FeO cathode material possessed highly EF catalytic activity after prolonged cycling. Inspired by the wonderful intrinsic properties and the easy fabrication procedure, the as-prepared 30G-FeO could be promising candidates as potential cathodic materials for high-performance EF oxidation.

In situ characterization of natural pyrite bioleaching using electrochemical noise technique

An in situ characterization technique called electrochemical noise (ECN) was used to investigate the bioleaching of natural pyrite. ECN experiments were conducted in four active systems (sulfuric acid, ferric-ion, 9k culture medium, and bioleaching solutions). The ECN data were analyzed in both the time and frequency domains. Spectral noise impedance spectra obtained from power spectral density (PSD) plots for different systems were compared. A reaction mechanism was also proposed on the basis of the experimental data analysis. The bioleaching system exhibits the lowest noise resistance of 0.101 MΩ. The bioleaching of natural pyrite is considered to be a bio-battery reaction, which distinguishes it from chemical oxidation reactions in ferric-ion and culture-medium (9k) solutions. The corrosion of pyrite becomes more severe over time after the long-term testing of bioleaching.

An <i>In Situ</i> Characterization for the Bioleaching Process of Natural Pyrite Using Electrochemical Noise Technique

An in situ characterization has been carried out for several active systems (sulfuric acid, ferric iron, 9k medium and bioleaching solutions) to investigate the bioleaching process of natural pyrite using electrochemical noise (ECN) technique. Spectral noise impedance spectra obtained from power spectral density (PSD) plots for the different systems were compared. It has been observed that the bioleaching system obtained the lowest noise resistance Rsn 0.101MΩ. The reaction mechanism was proposed based on experimental data analysis. The bioleaching process of natural pyrite has been identified as the main function of bio-battery reactions, which distinguishes from the chemical oxidation reaction for the ferric ion and 9k solutions.

Deactivation of poly(o-aminophenol) film electrodes by storage without use in the supporting electrolyte solution and its comparison with other deactivation processes. A study employing EIS

The effect of storage time without use (STWU) in the supporting electrolyte solution on the charge-transport parameters of poly(o-aminophenol) (POAP) film electrodes was studied by electrochemical impedance spectroscopy. STWU decreases the charge-transport rate of the polymer. This effect is herein called deactivation. Impedance diagrams of both nondeactivated and deactivated films in contact with a solution containing the p-benzoquinone/hydroquinone redox couple were interpreted on the basis of a model formulated for homogeneous conducting polymers, where the bathing electrolyte contains a redox pair that provides the possibility for electrons to leak from the film surface. Dependences of diffusion coefficients for electron (D e) and ion (D i) transport and interfacial resistances related to ion \(\left( {R_{\text{i}}^{{{\text{f}}|{\text{s}}}} } \right)\) and electron \(\left( {R_{{{\text{m}}|{\text{f}}}} ,R_{\text{e}}^{{{\text{f}}|{\text{s}}}} } \right)\) transfer across the polymer/solution and metal/polymer interfaces, respectively, on the degree of deactivation (θ d) of the polymer were obtained. These dependences were compared with those from previous work for POAP films deactivated by employing other procedures, such as high positive potential limits, soaking in a ferric ion solution, and prolonged potential cycling.

Deactivation of poly(o-aminophenol) film electrodes by storage without use in the supporting electrolyte solution and its comparison with other deactivation processes

The effect of storage time without use (STWU) in the supporting electrolyte solution on the conducting properties of poly(o-aminophenol) (POAP) film electrodes was studied. Cyclic voltammetry (CV), rotating disc electrode voltammetry (RDEV), and surface resistance (SR) were employed. The storage of a POAP film without use for time periods longer than 32h strongly reduces its electroactivity. Here, this effect is called deactivation. The attenuation of the voltammetric response of the polymer film with the increase of the storage time allows one to define a degree of deactivation (θd). A decrease of the electron transport rate (De) with the increase of the degree of deactivation of POAP films was obtained from RDEV measurements. This effect was attributed to the increase of the mean distance between active redox sites in the bulk of the POAP film. The relative surface resistance change (ΔR/R) of a gold film coated with POAP is also attenuated by the increase of the STWU. The attenuation was attributed to interfacial (gold/POAP) redox site distributions where the nearest neighbor distance between redox sites gradually increases as the degree of deactivation increases. The deactivation of POAP films by the STWU studied in this work was compared with deactivations caused by other electrochemical and chemical treatments, such as prolonged potential cycling (PPC), high positive potential limits (HPPL) and soaking in a ferric ion solution (SFeIS), described in previous work.