Iron chlorosis in olive in relation to soil properties

Chlorosis due to iron (Fe) deficiency is becoming severe in olive (Olea europaea L.) trees growing on some highly calcareous soils in southern Spain. We investigated the relationships between the incidence of Fe chlorosis in three olive varieties (`Hojiblanco', `Manzanillo' and `Picual') and soil properties. Leaf chlorophyll content, estimated by the mean value of three SPAD measurements during the growing season, was poorly correlated with soil carbonate content and reactivity. In contrast, it was significantly correlated with the clay content and with the amounts of Fe extracted with oxalate (Fe_ox), citrate/ascorbate (Fe_ca), and diethylendiaminepentaacetid acid (Fe_DTPA). This suggests that the content and reactivity of poorly crystalline Fe compounds play an important role in Fe nutrition. The three olive varieties did not differ significantly in their susceptibility to Fe chlorosis. Soil test critical levels separating chlorotic and non-chlorotic trees were 300 g clay kg^–1 soil and 0.35 g Fe_ox kg^–1 soil.     

Reduction of Fe(II)EDTA‐NO using Paracoccus denitrificans and changes of Fe(II)EDTA in the system

BACKGROUND: In the BioDeNO_X technology for NO_X removal from flue gas, bioreduction of Fe(II)EDTA‐NO and Fe(III)EDTA are core processes. In this study, a newly isolated strain, Paracoccus denitrificans, was used to reduce Fe(II)EDTA‐NO with glucose and Fe(II)EDTA as donor electrons. To better understand the change law of Fe(II)EDTA, the process of Fe(II)EDTA‐NO reduction by P. denitrificans with glucose and Fe(II)EDTA as electron donors was investigated, and the factors that might affect Fe(II)EDTA concentration were studied. RESULTS: For the bioreduction process of Fe(II)EDTA‐NO, P. denitrificans could use glucose and Fe(II)EDTA as electron donors. At different stages, primary electron donors were different, thereby affecting the concentration of Fe(II)EDTA in the system. It was also proved that this strain not only reduced Fe(III)EDTA with glucose as the electron donor but also secreted several substances that reacted with Fe(III)EDTA, resulting in increased Fe(II)EDTA concentration in the solution. CONCLUSIONS: This work has shown that P. denitrificans can reduce Fe(II)EDTA‐NO and Fe(III)EDTA simultaneously to regenerate NO_X absorption solution. © 2012 Society of Chemical Industry     

Application of crosslinked carboxymethyl konjac glucomannan in speciation of dissolved Fe(II) and Fe(III) in water samples

A new solid‐phase extraction technique has been developed for the speciation of trace dissolved Fe(II) and Fe(III) in environmental water samples with a microcolumn packed with crosslinked carboxymethyl konjac glucomannan (CCMKGM) prior to its determination by flame atomic absorption spectrometry (FAAS). Various influencing factors on the separation and preconcentration of Fe(II) and Fe(III), such as the acidity of the aqueous solution, sample flow rate and volume, and eluent concentration and volume, have been investigated systematically and optimized. Fe(III) could be quantitatively retained by CCMKGM in the pH range of 3.0–7.0, then the retained Fe(III) on the CCMKGM was eluted with 5.0 mol L^?1 HCl after cleaning with 0.01 mol L^?1 HCl to eliminate Fe(II) and determined by FAAS. Total Fe was determined after the oxidation of Fe(II) to Fe(III) by H₂O₂, and Fe(II) concentration was calculated by subtracting Fe(III) from total iron. The adsorption capacity of CCMKGM for Fe(III) was found to be as high as 162.3 mg g^?1. The detection limit (3σ) for Fe(III) was 1.5 μg L^?1 and the RSD was 3.5% (n = 11, c = 20 μg L^?1) with an enrichment factor of 50. The proposed method has been applied to the speciation of iron in water samples with satisfactory results. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of sulfite on reduction kinetics of Fe(III)NTA chelate

The reduction of Fe(III)NTA (ferric ion coordinated to nitrilotriacetic acid) by sulfite has been found to be first-order with respect to Fe(III)NTA and of order minus one with respect to Fe(II)NTA (one of the reaction products). The order of reaction with respect to HSO^?₃ has been determined to be unity when the molar ratio of Na₂SO₃ to total Fe(III) is less than five. In this paper, the role of sulfite in the reduction scheme is reconsidered, and the reduction rate expression in which the coordination of Fe³⁺ to HSO^?₃ is incorporated, is newly presented. The proposed rate equation covers all reaction data for molar ratios of Na₂SO₃ to total Fe(III) in the range of 1 to 25.     

Reductive transformation of 2-nitrophenol by Fe(II) species in γ-aluminum oxide suspension

Fe(II) adsorption onto γ-Al₂O₃ surfaces was studied in view of its high reactivity towards the aqueous reductive transformation of 2-NP. Kinetic measurements demonstrated that rates of 2-NP reduction were highly sensitive to pH, Fe(II) concentration and reaction temperature. An increase in pH, Fe(II) concentration or reaction temperature gave rise to an elevated density of Fe(II) adsorbed to mineral surfaces, which further resulted in an enhanced reaction rate of 2-NP reduction. By using the diffuse double layer (DDL) surface complexation model, the dominant Fe(II) surface complex that was responsible for the high reactivity was predicted to be the strongly bound ≡ SOFe⁺ functional group (represented by ≡ Al_stOFe⁺) onto γ-Al₂O₃ surfaces. In addition, cyclic voltammetry tests showed that the enhanced activity of Fe(II) species was attributed to the negative shift of the redox potential of Fe(III)/Fe(II) couple, resulted from the enhanced concentration of ≡ Al_stOFe⁺ complex.     

Influence of ionic speciation on electrocatalytic performance of polyaniline coated platinum electrode: Fe(III)/Fe(II) redox reaction

Porous-polyaniline coated Pt electrode (PANI/Pt) was electro-synthesized potentiodynamically in 0.1 M aniline + 0.5 M H₂SO₄ and morphologically characterized by scanning electron microscopy (SEM). Nature of predominant Fe-species in HCl and H₂SO₄ was checked by UV-vis spectrophotometry. Electrocatalysis of Fe(III)/Fe(II) reaction was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) for three different solution compositions viz. (i) FeCl₃/FeCl₂ in 1 M HCl, (ii) FeCl₃/FeCl₂ in 0.5 M H₂SO₄ and (iii) Fe₂(SO₄)₃/FeSO₄ in 0.5 M H₂SO₄. For different thicknesses of PANI, the peak current increased irrespective of the nature of the Fe-species, but the polarity of the charge on the Fe-species showed great influence on reversibility of electrocatalysis by PANI/Pt. The Donnan interaction of the polyaniline modified electrode for the three compositions was investigated with respect to [Fe(CN)₆]³⁻/H₂[Fe(CN)₆]²⁻ which are believed to be the predominant species present in K₃[Fe(CN)₆]/K₄[Fe(CN)₆] solution in 0.5 M H₂SO₄. The electrocatalytic performance of PANI/Pt for Fe(III)/Fe(II) redox reaction was found superior in HCl compared to that in H₂SO₄.     

Regeneration of [Fe(II)-NTA]− catalyzed by activated carbon in the simultaneous removal of sulphur dioxide and nitric oxide

The combined control of NO and SO₂ can be finished with the [Fe(II)-NTA]⁻ solution because [Fe(II)-NTA]⁻ is capable of binding NO. However, the ability of [Fe(II)-NTA]⁻ to bind NO may be lost quickly due to the fast oxidation of [Fe(II)-NTA]⁻ to [Fe(III)-NTA] by oxygen in the flue gases. To make it possible to put this technology into commercial application, efficient measures should be taken to regenerate [Fe(II)-NTA]⁻ to maintain the NO removal efficiency for a long time. The catalytic activity of activated carbon in the reproduction of [Fe(II)-NTA]⁻ has been investigated in a fixed-bed reactor. The experiments indicate that [Fe(II)-NTA]⁻ reproduction increases with [Fe(III)-NTA] and SO₃²⁻ concentrations as well as temperature. Fast flow and high pH are unfavourable for the reproduction of [Fe(II)-NTA]⁻. An NO removal efficiency of 80.11%–89.78% is sustained for a long period of time with the [Fe(II)-NTA]⁻ reproduction catalyzed by activated carbon. The reaction orders with respect to [Fe(III)-NTA] and SO₃²⁻ are 0.784 and 0.336, respectively. The apparent activation energy for this catalytic reaction is estimated to be 41.01 kJ mol⁻¹.     

Oxidation of 4‐nitrophenol in water over Fe(III), Co(II), and Ni(II) impregnated MCM41 catalysts

BACKGROUND: Nitrophenols are toxic constituents of the effluents of petroleum, textile, dye, iron and steel, foundries, pharmaceutical and electrical manufacturing industries. Aromatic nitro compounds are particularly resistant to normal chemical or biological oxidation making them environmentally persistent. Advanced oxidation using appropriate catalysts mineralize these organics to harmless final products. In this work, MCM41‐based catalysts incorporating Fe(III)‐, Co(II)‐ and Ni(II)‐ cations were used for oxidizing 4‐nitrophenol in water under variable conditions of reaction time, pH, mole ratio of the reactant and the oxidant, catalyst load, feed concentration, and temperature. RESULTS: The catalysts prepared were characterized with X‐ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), cation exchange capacity (CEC) and atomic absorption spectrometry (AAS) measurements. In typical reaction conditions of temperature 353 K, time 300 min, catalyst load 2 g L^?1 and 10^?3 mol L^?1 4‐nitrophenol, the oxidation was 48.7, 52.2 and 55.2% with H₂O₂ and 42.5, 56.6 and 60.2% without H₂O₂ for Fe(III)‐, Co(II)‐ and Ni(II)‐MCM41, respectively. Pseudo‐first‐order kinetics with kinetic constant of 2.0 × 10^?3 to 5.5 × 10^?3 Lg^?1 min^?1 was proposed along with a possible mechanism. 4‐nitrocatechol, 4‐nitropyrogallol, 1,2,4‐trihydroxybenzene, hydroquinone, acrylic acid, malonic acid, and oxalic acid were identified in the oxidation products. CONCLUSION: Introduction of Fe(III)‐, Co(II)‐ and Ni(II)‐ into MCM‐41 by impregnation produced effective catalysts for wet oxidation of 4‐nitrophenol. The catalysts were able to oxidize 4‐NP even without the presence of an oxidizing agent. The results suggest that the transition metal loaded MCM41 brings about a more effective interaction between 4‐NP molecules and OH radicals. Copyright © 2008 Society of Chemical Industry     

Adsorptive removal of tetracycline from water using Fe(III)-functionalized carbonized humic acid

Humic acid (HA) was carbonized at 300, 400 and 500 °C and then functionalized with 1 wt%–12 wt% Fe(III) respectively [CHA300/400/500-Fe(III)]. Adsorption of such Fe(III)-functionalized carbonized HA as adsorbents to aqueous tetracycline (TC: 25 mg·L⁻¹) was studied. The adsorption equilibrium time for CHA400-Fe(III) to TC was 6 h faster and the adsorption removal efficiency (R_e) was two times higher than that of HA/CHA. The adsorption R_e of CHA400-Fe(III) loaded 10% iron [CHA400-(10%)Fe(III)] to TC could reach 99.8% at 8 h and still kept 80.6% after 8 cycles. The adsorption kinetics were well fitted to the pseudo-second-order equation and the adsorption isotherms could be well delineated via Langmuir equations(R² > 0.99), indicating that the homogeneous chemical adsorption of TC occurred on the adsorbents. The main adsorption mechanisms of TC were complexation Fe(III) and hydrophobic distribution. Electropositive and electronegative repulsion between TC and CHA400-(10%)Fe(III) at lowly pH(2) and highly pH(8–10) respectively, leaded to the relatively low adsorption capacity and more notable influence of ion concentration. When the pH was between 4 and 8, TC mainly existed in neutral molecules (TCH₂), so the influence of ion concentration was not obvious. The dynamic adsorption results showed that the CHA400-(10%)Fe(III) could continuously treat about 2.4 L TC(27 mg·L⁻¹) wastewater with the effluent concentration as low as 0.068 mg·L⁻¹. Our study suggested a broad application prospect of a new, effective, low-cost and environment-friendly adsorbent CHA400-(10%)Fe(III) for treatment of low-concentration TC polluted wastewater.     

Elution Behavior of Metal Ions with Mixed Glycine-Nitric Acid Eluents in Dowex 50W-X8 Column: Separation of Th(IV), Ce(IV), Bi(III), Fe(III), and Al(III)

Abstract

Distribution coefficients (K) determined by the batch technique in acidic glycine media using Dowex 50W-X8 cation exchanger (H⁺?form, 100–200 mesh size) revealed that this medium can effectively be employed to separate a number of tetravalent and trivalent metal ions from bivalent metal ions. In fixed glycine (0.40 M) and varying concentration of nitric acid (0.10 to 1.0 M), a number of mixtures containing two or three metal ions were resolved on columns using about 8 g of exchanger. In 0.40 M glycine-1.0 M HNO₃ medium, Th(IV)/Ce(IV) were separated from Al(III)/Fe(III)/Bi(III)/Co(II)/Ni(II)/Cu(II)/Zn(II)/Cd(II)/Hg(II)/Pb(II)/Ag(I) and also Al(III)/Bi(III) from a number of divalent metal ions. In 0.40 M glycine-0.50 M HNO₃ medium, the resolution of following ternary mixtures were also achieved: Th(IV)/Ce(IV)-Al(III)/Bi(III)-Fe(III)/Co(II)/Ni(II)/Cu(II)/Zn(II)/Cd(II)/Hg(II)/Pb(II)/Ag(I). Th(IV)/Al(III)/Fe(III)/Bi(III) were also separated from other divalent metal ions in 1.60 M glycine-0.50 M HNO₃ medium. The values of K, elution characteristics of metal ions, elution curves, and the results of the resolution of a number of mixtures of metal ions along with standard deviations are reported.     

Reduction kinetics of Fe(III)NTA chelate by sulfite

Kinetics of the reduction of Fe(III)NTA (ferric ion coordinated to nitrilotriacetic acid) by sulfite were studied experimentally in aqueous solutions at 40-60°C and pH = 3.8-8.3. The reaction had been claimed to be a regeneration step of Fe(II) in the absorption of nitric oxide into aqueous solutions containing Fe(II)NTA and sulfites. The reaction rate could be expressed as first-order with respect to the concentration of Fe(III)NTA and of order minus one with respect to the concentration of Fe(II)NTA. The order of reaction with respect to HSO^?₃ was determined to be unity when the molar ratio of Na₂SO₃ to Fe(III)NTA was less than 5.     

Synthesis and characterization of a surface imprinting silica gel polymer functionalized with phosphonic acid groups for selective adsorption of Fe(III) from aqueous solution

A Fe(III) ion‐imprinted silica gel polymer functionalized with phosphonic acid groups (IIP‐PA/SiO₂) was prepared with surface imprinting technique by using Fe(III) ion as template ion, grafted silica gel as support, and vinylphosphonic acid as functional monomer. The polymer was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller, and thermogravimetric analysis. The synthesized imprinted silica gel polymer was used as a sorbent for Fe(III) adsorption. The adsorption properties, such as the effect of solution pH, adsorption kinetic, adsorption isotherm, adsorption selectivity as well as the regeneration of sorbent were studied. The results showd that the prepared sorbent (IIP‐PA/SiO₂) had a short adsorption equilibrium time (12 min) and high adsorption capacity (29.92 mg g^?1) for Fe(III) at the optimal pH of 2.0. The selectivity coefficients of the sorbent for Fe(III) in presence of Cr(III), M_n (II), and Zn(II) were 51.76, 27.86, and 207. 76, respectively. Moreover, the adsorption capacity of the prepared sorbent did not decrease significantly after six repeated use. Thus, the prepared ion‐imprinted silica gel polymer was a promising candidate sorbent for the selective adsorption of Fe(III) from aqueous solutions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45165.     

Use of deep eutectic solvent as extractant for separation of Fe (III) and Mn (II) from aqueous solution

In this work, we used deep eutectic solvent (DES) composed of decanoic acid and lidocaine, which is characterized as a green solvent, for separation of Fe (III), which is the most-used metal in the world, and Mn (II), which is currently being used in many industries. We found that the pH of the initial metal solution strongly influenced the extraction mechanism. Fe (III) can be extracted at pH 1.0–2.0 due to the ion pair reaction between Fe³⁺ and decanoic anion, while at higher pH, the extraction mechanism cannot be evaluated due to formation of precipitation at the aqueous phase. In the case of Mn (II), the ion pair reaction occurred at pH of lower than 2.2 and higher than 3.5, while from pH 2.2 to 3.5, the cation exchange between Mn²⁺ and lidocaine cation probably dominated the extraction process. The DES concentration needed to reach the complete separation of Fe (III) was about 25 g/L, while Mn (II) was completely extracted using about 300 g/L of DES. The selectivity of this method was very high when was applied in the separation of Fe (III) from Mn (II).     

Lime-induced iron chlorosis in sugarcane

Lime-induced chlorosis is a potential problem on most calcareous soils particularly in arid and semi-arid climates affecting most of the plants grown on them. Bicarbonates, phosphates, calcium, iron inactivation in plant tissue and organic anions have been held responsible as the mechanism leading to the disorder which is still not fully understood, and there is a lack of agreement as to the primary factor responsible for lime-induced chlorosis. To date, no hypothesis has adequately explained why chlorosis occurs on some high lime soils and not on others. Likewise, the nutrient ratios, K/Ca, P/Fe and Fe/Mn considered as diagnostic criteria for lime-induced chlorosis, have shown inconsistency. The presence of calcium carbonate, bicarbonate, calcium and imbalance of nutrient cations in the growth medium, injudicious addition of phosphates, quality of irrigation water, and other soil and plant factors have been held responsible for the disorder. Amelioration of lime-induced chlorosis by (i) acidification of calcareous soils, (ii) use of iron salts, (iii) use of synthetic iron chelates, and (iv) by management practices including the selection and development of varieties resistant to lime-induced iron chlorosis, is discussed. Suggestions for future research work are made.     

Structural Fe(III) reduction in smectites

Manipulation of the oxidation state of structural Fe in clay minerals is a potential method for altering important physical–chemical properties of the clay and several studies have focussed on this phenomenon. This paper summarizes current knowledge on reduction of structural Fe(III) in iron-rich dioctahedral smectites and partial stabilization of Fe(II) in reduced SWa-1 ferruginous smectite via fixation of Li⁺ cations upon heating. Fe(III) in Fe-rich dioctahedral smectites was completely reduced in citrate–bicarbonate buffer using sodium dithionite. Progress in the reduction or reoxidation process was followed by monitoring the Fe(II)–O–Fe(III) intervalence electron transfer transition using visible spectroscopy at 730 nm. Reduction proceeds from basal surfaces rather than from particle edges. One study found that trioctahedral domains and vacancies may occur within the structure of reduced minerals, but another study indicated less radical structural changes. Fully reoxidized minerals contain less OH groups. About 20% of total Fe can be stabilized as Fe(II) in reduced SWa-1 via Li⁺-saturation and heating the Li-form of a highly reduced mineral in N₂ atmosphere at 260 °C for 24 h. Part of the Li⁺ is trapped in previously vacant octahedral sites, forming trioctahedral AlFe(II)LiOH or Fe(III)Fe(II)LiOH groupings.     

Spectroscopic and Thermal Studies of Mn(II), Fe(III), Cr(III) and Zn(II) Complexes Derived from the Ligand Resulted by the Reaction Between 4-Acetyl Pyridine and Thiosemicarbazide

Transition metal complexes of Mn(II), Fe(III), Cr(III) and Zn(II) metal ions with a general formulas [Mn(L)₂(Cl)₂]·4H₂O (I), [Fe(L)₂(Cl)₂]·Cl·6H₂O (II), [Cr(L)₂(Cl)₂]·Cl·6H₂O (III) and [Zn(L)₂(Cl)₂]·2H₂O (IV) where L = 4-acetylpyridine thiosemicarbazone, have been synthesized and interpreted using CHN elemental analysis, magnetic susceptibility measurements, molar conductance, thermal analysis and spectroscopic techniques; i.e., infrared, electronic UV/vis, ¹H-NMR and mass. The manganese(II), ferric(III), chromium(III) and zinc(II) complexes have octahedral geometry. The molar conductance measurements reveal that the Mn(II) and Zn(II) chelates are non-electrolytes but Fe(III) and Cr(III) have an electrolytic behavior. The IR spectra show that the 4-acetylpyridine thiosemicarbazone free ligand is coordinated to the metal(II) chlorides as a neutral bidentate ligand through both of the lone pair of electrons of the C=N azomethine group and C=S group. X-ray powder diffraction gives an impression that the resulting complexes are amorphous and different from the start materials. The thermogravimetric studies indicate that uncoordinated water molecules are lost in the first and second decomposition steps. The activation thermodynamic parameters E*, ΔH*, ΔS* and ΔG* are estimated from the differential thermogravimetric analysis (DTG) curves using Horowitz–Metzger (HM) and Coats–Redfern (CR) methods. The ligand and its complexes have been screened for antibacterial and antifungal activities against two bacteria; i.e., Escherichia coli (Gram −ve) and Bacillus subtilis (Gram +ve) and two fungi, i.e., tricoderma and penicillium activities).     

Phosphate availability in calcareous Vertisols and Inceptisols in relation to fertilizer type and soil properties

The availability to plants of fertilizer phosphorus (P) applied to soil, as measured by chemical extraction, is used to estimate P fertilizer needs. We studied the availability of P, applied as monocalcium phosphate (MCP) powder, ordinary superphosphate (OSP) granules and diammonium phosphate (DAP) granules in 24 calcareous Vertisols and Inceptisols of Andalusia, Spain, by using laboratory incubation techniques. The soils differed widely in their P adsorption- and Ca-phosphate precipitation-related properties. For MCP, availability (defined as the proportion of added P that is recovered by extraction with NaHCO₃ or is isotopically exchangeable) decreased markedly with incubation time and increasing addition rate. The mean recoveries after 180 d of incubation at field capacity at a rate of 246 mg P kg^–1 soil were 17% for Olsen P, 38% for Colwell P, and 16% for isotopically exchangeable P (IEP). Increasing the application rate to 2460 mg kg^–1 resulted in recoveries of 6% for Olsen P, 25% for Colwell P, and 4% for IEP. While IEP-based recovery was not significantly correlated to any soil property, that based on Olsen P (and, to a lesser extent, Colwell P) decreased sharply with increase in the ratio of clay (or Fe oxides) to total (or active) calcium carbonate equivalent. Accordingly, Olsen P might overestimate P availability in those soils relatively rich in carbonate and poor in clay and Fe oxides. On the other hand, recovery of applied P from soils containing more clay and Fe oxides, by a sequential extraction (with H₂O, two 0.5M NaHCO₃ treatments, 0.5M HCl), was lower than 100%, thereby suggesting phosphate occlusion by Fe oxides or clay.Availability of the fertilizers tested 90 d after application was found to decrease in the following order: MCP powder (rate, 246 mg kg^–1) > DAP granules (rate, 547 mg kg^–1) > MCP powder (rate, 738 mg kg^–1) > OSP granules (rate, 308 mg kg^–1). Differences between fertilizers tended to increase with increasing carbonate content in the soil. This may have been due to precipitation of Ca phosphates caused by the presence of Ca in the fertilizer and the high Ca- supplying capacity of the more calcareous soils.     

Advances in electrochemical Fe(VI) synthesis and analysis

Hexavalent iron species (Fe(VI)) have been known for over a century, and have long-time been investigated as the oxidant for water purification, as the catalysts in organic synthesis and more recently as cathodic charge storage materials. Conventional Fe(VI) syntheses include solution phase oxidation (by hyphchlorite) of Fe(III), and the synthesis of less soluble super-irons by dissolution of FeO₄ ²⁻, and precipitation with alternate cations. This paper reviews a new electrochemical Fe(VI) synthesis route including both in situ and ex situ syntheses of Fe(VI) salts. The optimized electrolysis conditions for electrochemical Fe(VI) synthesis are summarized. Direct electrochemical synthesis of Fe(VI) compounds has several advantages of shorter synthesis time, simplicity, reduced costs (no chemical oxidant is required) and providing a possible pathway towards more electro-active and thermal stable Fe(VI) compounds. Fe(VI) analytical methodologies summarized in this paper are a range of electrochemical techniques. Fe(VI) compounds have been explored as energy storage cathode materials in both aqueous and non-aqueous phase in “super-iron” battery configurations. In this paper, electrochemical synthesis of reversible Fe(VI/III) thin film towards a rechargeable super-iron cathode is also summarized.     

Green and efficient synthesis of an adsorbent fiber by preirradiation‐induced grafting of PDMAEMA and its Au(III) adsorption and reduction performance

N ,N ‐Dimethylamino ethyl methacrylate (DMAEMA) is covalently bonded on a commercial polyethylene‐coated polypropylene skin‐core structure fiber (PE/PP) in aqueous and MeOH/H₂O solutions by a one‐step green reaction using radiation‐induced graft polymerization. The effects of the absorbed dose and solvent system on grafting yield are investigated, while the chemical and physical properties of the functionalized fiber are also evaluated. The fiber with a D_g of 51.6% exhibited good adsorption capacity of Au(III) ions over a large range of concentrations (from 10 to 2.5 g L^?1) in both batch and flow‐through adsorption tests. The highest capacity of Au was 949.3 mg g^?1. After elution, the adsorbents can be reused without any further regeneration for at least five adsorption‐desorption cycles. Additionally, the fibers show high selectivity for Au(III). The distribution coefficient of Au(III) is 10⁴ to 10⁵ times higher than that for Cu(II), Fe(III), Ni(II), and Pb(II) even at 100 times lower Au(III) concentration compared to the co‐existing metal ion concentration. This study provides an effective and novel approach for gold recovery from aqueous solutions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44955.