Effects Of Fe2 Research Articles

Ferronickel preparation using Ni-Fe co-deposition process

Nucleation mechanism and technological process for Ni-Fe co-deposition with a relatively high Fe2+ concentration surrounded were described, and the effects of Fe2+ concentration, solution pH, temperature, and sodium dodecyl sulfonate concentration were investigated. Electrochemical experiments demonstrate that iron’s electrodeposition plays a leading role in the Ni-Fe co-deposition process, and the co-deposition nucleation mechanism accords with a progressive nucleation. Temperature increase does favor in increasing nickel content in the ferronickel (Ni-Fe co-deposition products), while Fe2+ concentration increase does not. When solution pH is higher than 3.5, nickel content in the ferronickel decreases with pH because of the hydrolysis of Fe2+. With the current density of 180 A/m2, Na2SO4 concentration of 100 g/L and Ni2+ concentration of 60 g/L, a smooth ferronickel deposit containing 96.21% Ni can be obtained under the conditions of temperature of 60 °C, Fe2+ concentration of 0.3 g/L, solution pH of 3 and sodium dodecyl sulfonate concentration of 40 mg/L.

Hexuronates influence the oligomeric form of the Dps structural protein of bacterial nucleoid and its ability to bind to linear DNA fragments

Proteins of the Dps family perform a dual function in bacterial cells. As ferritins, they protect cells from destructive effects of Fe2+ ions, while interacting with DNA they condense the genome in the absence of nutrients. The ability of Dps to self-aggregate is of a great importance. The way of genome remodelling from the condensed state to the active one is not yet known. Here, the effects of two sugar ligands on Dps interaction with DNA have been studied in vitro. For the first time it was demonstrated that D-glucuronate and D-galacturonate, but not D-glucose, can decompose the dodecameric structure of the protein and D-glucuronate stimulated the formation of binary complexes with the linear DNA fragments. As a result of flexible molecular docking, it was found that the molecules of all three sugars potentially can form clusters inside the protein cavity of Dps, but D-glucuronate and D-galacturonate were also bound in the region of intersubunit contacts of oligomer. The consequent destabilization of the intersubunit bonding network can, thus, be the main factor provoking the protein decay to the smaller oligomeric forms. Such a structural rearrangement, leading to a reduction in aggregation, may play a key role in genome decondensation during cell transition to the phase of rapid growth.

Incorporation of dolomite reduces iron toxicity, enhances growth and yield, and improves phosphorus and potassium nutrition in lowland rice (Oryza sativa L)

Management options to reduce the negative impacts of iron (Fe2+) toxicity in lowland rice (Oryza sativa L.) are limited. Improving productivity and ensuring sustainability of such systems requires a sound ecophysiological understanding of this widespread problem. The effectiveness of dolomite [CaMg (CO3)2] application to increase the availability of soil phosphorus (P) to rice plants, and to decrease the bioavailability of Fe2+ was tested at two locations, one with and one without effects of Fe2+ toxicity. We used a Fe2+-susceptible and a Fe2+-tolerant rice variety, with and without the application of dolomite at a rate of 1 t ha−1for three consecutive seasons. In a pot experiment, we studied the shoot and root growth, and soil and plant P and Fe nutrition with the application of 0, 1 and 10 t ha−1 of dolomite in an iron-toxicity affected soil. With the application of dolomite, both in the field and in the pot experiment, the exchangeable soil Fe2+ concentration decreased with an increase in soil pH and P availability. Plant height, shoot and root dry weight, grain yield, and P and potassium content increased, whereas the organ Fe concentration and content decreased with a greater response by the Fe2+-susceptible rice variety than by the tolerant variety, and with the greatest effect at the Fe2+-toxicity-affected site. Application of dolomite to lowland rice fields affected by Fe2+ toxicity can increase grain yield, while reducing the negative impacts of Fe2+ toxicity. The magnitude of these positive responses would vary depending on variety, season and soil conditions.

Monodisperse hexagonal SrFe12O19 nanoflake with enchanced magnetic properties

Monodisperse SrFe12O19 (SrM) nanoflakes were successfully fabricated via a modified hydrothermal method. The effects of Fe3+/Sr2+ (RF/S) and OH−/NO3− (RO/N) molar ratio on phase, structure and morphology of the products were investigated by XRD, FT-IR, FESEM, and TEM. Meanwhile, the magnetic properties of the product were investigated via vibrating sample magnetisem (VSM). Results demonstrated that when the RF/S=5 and RO/N=2, the single phase SrFe12O19 particles were obtained. The as-obtained SrFe12O19 particles had monodisperse nanoflake structure and nano-micro scale in vertical and horizontal direction of SrM ferrite particle. The magnetic property results showed that such structure SrM ferrite particle had prospective saturation magnetization and coercivity, the largest values of Ms and Hc were 62.96emu/g and 94.83kA/m, respectively, which make it have a potential application as magnetic recording media and magneto-optical devices material.

The Effects of Fe2+ on the Aggregation Behavior of Residual Hydrophobic Modified Polyacryamide

The influences of Fe2+ on the aggregation behavior of residual hydrophobic modified polyacryamide (HMPAM) in treated oily wastewater were studied by fluorescence spectrum and DLS. The result of I1/I3 showed that the polarity of hydrophobic domain increased and the size of hydrophobic domain may be decreased with the increasing of Fe2+ in produced water. Fe2+ was helpful for the increase of hydrophobic domain, therefore due to the aggregation degree for HMPAM.

Effects of Fe 2+ and Fe 3+ on Algal Proliferation in a Natural Mixed Algal Colony in Algae-Rich Raw Water in Southern China

As a necessary micronutrient for algal growth, iron (Fe) has importanteffects on the physiological metabolism and enzymatic reactions of algae. There arevarious forms of iron in nature, and soluble iron exists mainly in two forms: Fe2+ andFe3+. In this study, a series of experiments were designed to compare the effects ofFe2+ and Fe3+ on the growth of natural mixed algal colonies and single-species coloniesof Scenedesmus quadricauda. The results show that Fe2+ and Fe3+ have different effectson the reproductive processes of these two algal populations. The optimal growthconcentration of both Fe2+ and Fe3+ for natural mixed algae is 0.3 mg/L; at that concentration,algal biomass reaches its peak, with values of 1.74 × 106 cells/L and 6.82× 105 cells/L for the two iron forms, respectively. At the same time, the average growthrates of these algae also reach their maximum, which are 0.3620 d–1 and 0.3398 d–1,respectively. The optimal growth concentrations of Fe2+ and Fe3+ for S. quadricaudaare about 0.4 mg/L. We propose that Fe2+ exhibits higher biological time-effectivenessthan Fe3+ for algal reproduction, and while Fe2+ and Fe3+ exhibit similar facilitation in thegrowth of both natural mixed algae and S. quadricauda, differences exist between theirfacilitation effects. The results of the study further suggest that problems involving ironuptake priority and inter-specific competition could arise during the reproductive processin mixed algal colonies.

THE EFFECTS OF ISOLATED FRACTIONS OF RED PEPPER CAPSICUM ANNUUM L. ON THE MITOCHONDRIAL PERMEABILITY TRANSITION PORE AND LIPID PEROXIDATION

Fruit proteins, seed proteins and capsaicinoids fractions were isolated from red pepper of Capsicum annum L. plants family and their effects on mitochondrial permeability transition pore (MPTP) and lipid peroxidation of rat liver were studied in vitro. Seed proteins did not influence to MPTP; however fruit proteins caused MPTP to open and led to mitochondrial membrane permeabilization. Opening of the MPTP causes massive swelling of mitochondria; capsaicinoids fractions inhibited the swelling process of mitochondria and caused the closed state of the MPTP. Fruits and seeds protein fractions from red pepper did not reduce the effect of Fe2+/ascorbate-induced mitochondrial swelling and had no effect on the accumulation of malondialdehyde (MDA) in the membranes of mitochondria. Capsaicinoid fraction had a concentration-dependent inhibitory effect on the Fe2+/ascorbate-dependent swelling of mitochondria and of lipid peroxidation. Half-maximal inhibitory concentration (IC50) on the swelling of mitochondria fraction was 2 µg/ml. Сapsaicinoids fraction prevented the effect of Fe2+/ascorbate on mitochondria and reduced the accumulation of MDA in membrane. Complete inhibition of lipid peroxidation was shown at a 50 µg/ml capsaicinoids concentration. Capsaicinoids, reducing the membrane destructive effects of Fe2+/ascorbate, had antioxidant properties and a protective effect on mitochondria. The obtained results showed the presence of different compounds in red pepper differently affecting MPTP and lipid peroxidation.

In situ microwave-enhanced electrochemical reactions at stainless steel: Nano-iron for aqueous pollutant degradation

Iron nanoparticle deposition and stripping are observed from aqueous Fe2+ solution at pH3 on stainless electrodes in the presence of focused microwave activation. The effects of Fe2+ concentration and microwave power are evaluated. It is shown that the resulting iron nanoparticle deposit (i) gives well-defined anodic stripping responses, (ii) is readily released into the solution phase, and (iii) is highly reactive towards chlorinated hydrocarbons such as trichloroacetate. The combined effects of increased mass transport and localized microwave heating improve pollutant degradation treatments.

Photodegradation of the endocrine-disrupting chemicals benzophenone-3 and methylparaben using Fenton reagent: Optimization of factors and mineralization/biodegradability studies

Benzophenone-3 (BP3) and methylparaben (MPB) are two emerging pollutants, whose endocrine disrupting activity on different living beings has been reported. Therefore, removal of these pollutants from aqueous samples using photo-Fenton technology was assessed. Effects of Fe2+ and H2O2 initial concentrations on pollutants photo-degradation were analyzed and a face centered, central composite design was carried out for determining the optimal conditions, in the evaluated range, that conducted to higher substrate elimination.Results indicated that Fe2+ and H2O2 initial concentration and the interaction between them affect significantly the process. In addition, experiments varying BP3 and MPB initial concentrations showed that elimination rate increases with an increase in the substrate initial concentration and a pseudo-first-order kinetic can be used to describe pollutants degradation. Under optimal conditions compounds were eliminated totally after 120 min of treatment. Dissolved organic carbon studies illustrated that more than 60% of contaminants were mineralized and biodegradability analysis indicated that this factor increased gradually during 300 min of photo-Fenton treatment.

High efficient removal of molybdenum from water by Fe2(SO4)3: Effects of pH and affecting factors in the presence of co-existing background constituents

Comparatively investigated the different effects of Fe2(SO4)3 coagulation-filtration and FeCl3 coagulation-filtration on the removal of Mo (VI). And the influence of calcium, sulfate, silicate, phosphate and humic acid (HA) were also studied. The following conclusions can be obtained: (1) compared with the case of FeCl3, Fe2(SO4)3 showed a higher Mo (VI) removal efficiency at pH 4.00–5.00, but an equal removal efficiency at pH 6.00–9.00. (2) The optimum Mo (VI) removal by Fe2(SO4)3 was achieved at pH 5.00–6.00; (3) The presence of calcium can reduce the removal of Mo (VI) over the entire pH range in the present study; (4) The effect of co-existing background anions (including HA) was dominated by three factors: Firstly the influence of co-existing background anions on the content of Fe intercepted from water (intercepted Fe). Secondly the competition of co-existing anions with Mo (VI) for adsorption sites. Thirdly the influence of co-existing background anions on the Zeta potential of the iron flocs.

Effective removal of nemacide fosthiazate from an aqueous solution using zero-valent iron

In this study, the removal of fosthiazate in an aqueous solution using zero valent iron (ZVI) and the related removal reaction mechanism were investigated. The results indicate that the dissipation of fosthiazate adheres to a pseudo-first order reaction law. The apparent rate constant of fosthiazate removal could be improved by increasing the ZVI dosage, control temperature and initial pH. The observed pseudo-first-order degradation rate constants (Kobs) of fosthiazate removal using ZVI were varied in the different electrolyte solutions, and were determined as follows: Kobs (MgSO4) < Kobs (KCl) < Kobs (Control) <Kobs (NaCl) < Kobs (CaCl2) < Kobs (NaNO3) < Kobs (Na2SO4). In addition, the effects of Fe2+ and Fe3+ ions on the fosthiazate removal were also investigated, and the fosthiazate removal efficiencies were measured as 1.3% and 5.7% with Fe2+ and Fe3+, respectively. The characterizations of ZVI before/after the reaction were employed to gain insight into the reaction mechanism. Finally, the main degradation products were investigated by means of an Agilent 1100 LC/MSD Ion Trap.

Enhanced biomass production, lipid yield and sedimentation efficiency by iron ion

Effects of Fe3+ on the biomass production, lipid accumulation of Monoraphidium sp. FXY-10 were investigated. Further residual Fe3+ in the culture medium on the sedimentation efficiency have been also studied. The biomass and lipid productivity of microalgae exhibited an increasing tendency with the concentrations of iron ion augmenting. 150μM iron ion added into the culture medium result in highest DCW at 1.42gL−1 while the maximum lipid productivity of 10.71mgL−1d−1 were obtained at 50μM. The results showed that appropriate concentrations of iron ion was beneficial for biomass production and lipid accumulation but higher concentration of that will be more in favor of the sedimentation efficiency of Monoraphidium sp. FXY-10.

Bifunctional NaGdF4:Yb, Er, Fe nanocrystals with the enhanced upconversion fluorescence

NaGdF4:Yb, Er nanocrystals doped with Fe3+ were synthesized by a facile hydrothermal method. The upconversion emissions in a broad range from 200 to 700nm were measured under 980nm laser excitation. The luminescence intensity can be improved greatly by Fe3+ doping. In addition to the typical upconversion emission of Er3+ ions, the violet emission from Gd3+ is explained by the energy transfer from Er3+ to Gd3+. Powder X-ray diffraction patterns reveal that Fe3+ can enter crystal sites interstitially and substitutionally. The effects of Fe3+ doping on morphology, crystal growth and emission properties of particles are discussed in detailed. Furthermore, these nanocrystals exhibit paramagnetic properties and have the potential applications in bimodal bioimaging in virtue of their upconversion luminescent and paramagnetic properties.

A comparative study on oxidative degradation of 2,4-dichlorophenol and 2,4-dichlorophenoxyacetic acid by ammonium persulfate

The degradation of 2,4-dichlorophenol (2,4-DCP) and 2,4-dichlorophenoxyacetic acid (2,4-D) by ammonium persulfate under various activation conditions was investigated. The effect of the initial oxidant concentration, pH, temperature, and Fe2+ concentrations were studied. The rate of 2,4-DCP and 2,4-D oxidation was proportional to the concentration of persulfate. The optimal pH for 2,4-DCP degradation was 9.0, while for the 2,4-D, it was 3.0. The effect of temperature on the kinetics of 2,4-DCP and 2,4-D oxidation was examined, and it was demonstrated that increasing the temperature from 25 to 50°C accelerated the oxidation rate of both contaminants. The effects of Fe2+ concentrations and the optimal ratio of persulfate to Fe2+ were studied. Synergistic activation of persulfate by heat and Fe2+ was also investigated to enhance the oxidation of 2,4-DCP and 2,4-D. Under optimal experimental conditions, when the persulfate to Fe2+ molar ratio was 1:2 at 50°C, the complete oxidation of 2,4-DCP and 2,4-D was achieved after about 45 and 60 min. In any case, the 2,4-DCP was oxidized faster and more efficiently than 2,4-D.

Enhancement of anammox performance by Cu(II), Ni(II) and Fe(III) supplementation

This study explored the influence of metal ion addition on specific anaerobic ammonium oxidation activity (SAA). Batch assays were used to demonstrate the enhancement of the SAA upon the addition of Cu2+, Ni2+ and Fe3+. The SAA was enhanced by 41.0% when the Cu2+ concentration was below 1mgL−1, while it was improved by 63.5% at Ni2+ concentrations below 1.74mgL−1. An enhancement of 533.2% was obtained when 3.68mgL−1 Fe3+ was supplied. The effects of Fe3+, Cu2+ and Ni2+ on the SAA were analyzed and optimized by a response surface methodology, which demonstrated that the interaction between Fe3+ and Cu2+ was significant and that 6.61mg Fe3+ L−1, 1.18mgCu2+L−1 and 1.11mgNi2+L−1 were the optimal values for metal dosing. Subsequently, an Fe3+–Cu2+–Ni2+ continuous test was carried out under optimal conditions and revealed that the addition of Fe3+, Cu2+ and Ni2+ could stimulate the reactor potential at ambient temperature. The maximum nitrogen removal rate (NRR) of the test reactor was 52.8% higher than that of the control reactor (8.1 versus 5.3kgNm−3d−1). Moreover, a continuous test conducted by adding Fe3+ achieved an average nitrogen removal efficiency and maximum NRR of 67.4% and 4.9kgNm−3d−1, respectively, while the corresponding values of the control test were 64.7% and 4.1kgNm−3d−1, respectively. Altogether, appropriate dosages of Cu2+, Ni2+ and Fe3+ can significantly enhance the SAA and improve the reactor capacity at ambient temperature.

Effects of Sm&lt;sup&gt;3+&lt;/sup&gt; on Microstructure and Magnetic Properties of Ni&lt;sub&gt;0.4&lt;/sub&gt;Zn&lt;sub&gt;0.6&lt;/sub&gt;Sm&lt;sub&gt;x&lt;/sub&gt;Fe&lt;sub&gt;2-X&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt;(x=0~0.07) Ferrites

The effects of Fe3+substitutions by Sm3+on microstructure and magnetic properties of Ni0.4Zn0.6Fe2-xSmxO4ferrites prepared by conventional solid-state reaction method were investigated. With increasing Sm3+content, the lattice parameter ɑ and sintered density of sintered samples increase, while the real part of permeability and magnetic loss tangent decrease. Samples carried out at 1250°C for 4h resulted in materials with cubic spinel phase, but a small amount of SmFeO3was also formed. Magnetic properties results showed that the super-exchange interaction between octahedral B sites and tetrahedral A sites was badly impaired and the net overall magnetic moment (m=mB-mA) has an obvious decrease. It was also found that in these compounds Fe-Fe interaction dominates, the Sm-Fe interaction (3d-4f coupling) having a minor effect.

Enhanced lipid accumulation of green microalga Scenedesmus sp. by metal ions and EDTA addition

Effects of Fe3+ (0–0.12g/L), Mg2+ (0–0.73g/L) and Ca2+ (0–0.98g/L) on the biomass and lipid accumulation of heterotrophic microalgae were investigated in dark environment. The biomass and lipid production exhibited an increasing trend with increasing the concentrations of metal ions. In cultures with 1.2×10−3g/L Fe3+, 7.3×10−3g/L Mg2+ and 9.8×10−4g/L Ca2+, the maximum biomass, total lipid content and lipid productivity reached 3.49g/L, 47.4% and 275.7mg/L/d, respectively. More importantly, EDTA addition (1.0×10−3g/L) could enhance the solubility of metal ions (iron and calcium) and increase their availability by microalgae, which evidently promote the lipid accumulation. Compared with the control, the total lipid content and lipid productivity increased 28.2% and 29.7%, respectively. These show that appropriate concentrations of metal ions and EDTA in the culture medium were beneficial to lipid accumulation of heterotrophic Scenedesmus sp. cells.

Technical and economic feasibility of polyester dyeing wastewater treatment by coagulation/flocculation and Fenton's oxidation

This study aims to investigate the efficiency of individual and integrated processes applied to organic matter abatement and biodegradability improvement of a polyester dyeing wastewater, namely coagulation/flocculation combined with Fenton's reagent (Approach 1), Fenton oxidation alone (Approach 2) and its integration with coagulation/flocculation (Approach 3). The effects of Fe2+ dose, initial concentration of the oxidant (H2O2) and temperature during Fenton's oxidation were evaluated in Approaches 1 and 2, whereas in Approach 3 the influence of pH and flocculant dose was also assessed, during the coagulation/flocculation stage. Toxicity and biodegradability of the final effluent were also evaluated. After oxidation, a slight increase in the specific oxygen uptake rate of the effluent was observed (from 27.0 up to 28.5–30.0 mg O2/(gVSS h)) and the inhibition to Vibrio fischeri was eliminated. An effluent that complies with discharge standards was obtained in all cases; however, Approach 3 revealed to be a promising solution for treating this effluent as it leads to smaller operating costs. Therefore, the use of dissolved iron resulting from Fenton's oxidation as coagulant in the second stage was shown to be an innovative, efficient and economically attractive strategy for treating these effluents.

Influence of Fe2+-sodium persulfate on extracellular polymeric substances and dewaterability of sewage sludge

Activated persulfate generated from Fe2+-sodium persulfate (SPS) was used as a conditioner for dewatering of waste activated sludge. The effects of Fe2+-SPS on dewaterability were investigated by specific resistance to filtration (SRF) and capillary suction time (CST), as well as further confirmed the results with diaphragm filter press dewatering process in laboratory. The amount of extracellular polymeric substances (EPS) and zeta potentials were analyzed. With 30 mg Fe2+ per gram dry solid (DS) and 100 mg SPS per gram DS, 89.0% of SRF and 84.1% of CST reductions were achieved, respectively. Furthermore, the dewatered cake moisture content was as low as 52.6% in the diaphragm filter press dewatering. The EPS fractions and zeta potential of the sludge floc were found to have significantly changed during the Fe2+-SPS conditioning. Proteins and polysaccharides contents in filtrate all increased with increase in the amount of Fe2+-SPS, but decreased in tightly bound EPS (TB-EPS). The change of proteins content in loosely bound EPS (LB-EPS) was more significant than polysaccharides. Scanning electron microscope images further demonstrated that the Fe2+-SPS pre-treatment ruptured the sludge floc resulting in the formation of permeable and incompressibility structure in filtration process.

The Effect of Fe&lt;sup&gt;3+ &lt;/sup&gt;on Microbial Growth and Physical and Chemical Properties of Activated Sludge

The method of activated sludge has been widely used in the process of sewage treatment for its high-efficiency and low-consumption. The effect of Fe3+ on microbial growth and physical and chemical properties of activated sludge were studied to obtain relevant parameters for the running of activated sludge system in this paper. Firstly, study on the effect of Fe3+ on microbial growth was carried out. The experiment results showed that the lag phase of microbial growth was obviously reduced with the presence of Fe3+, obtaining advancing into the logarithmic phase. Whats more, the value of OD600 reached to the maximum of 0.615 at 12h when the concentration of Fe3+ was 30mg/L. Secondly, the effects of Fe3+ on the wastewater treatment and that of the performance index include SVI and MLSS were studied. The results indicated that SVI decreased with increasing the dosages of Fe3+,while MLSS and removal rate of COD obviously increased which reach to the maximum of 88.21% when the concentration of Fe3+ was 30mg/L.