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Objective: This study aimed to assess the efficacy of different oral iron preparations prescribed for prevention of iron deficiency anemia in healthy infants. Methods: This retrospective study enrolled infants aged between 6 and 12 months who were initiated on iron prophylaxis at four months of age. Enrolled children consistently used specific iron preparations (ferrous, ferric or liposomal iron) and had their complete blood counts and serum ferritin levels assessed within the 6–12 month timeframe. Blood values and iron prophylaxis type (ferrous (Fe+2), ferric (Fe+3), liposomal iron) were recorded. Chi-square test was used to compare the hemoglobin and ferritin levels levels between groups. Univariate and multivariate regression analyses assessed the risk of anemia. Results: The study included 371 children (ferrous sulphate - 60, iron hydroxide-polymaltose complex - 137 and liposomal ferric pyrophosphate - 174) with a mean (SD) age 9.1 (1.3) mo. Iron deficiency in different groups were: liposomal iron (46.0%), ferric iron (44.5%), and ferrous iron (5.0%). Mean (SD) serum ferritin levels (µg/L) were higher in the ferrous group [30.1 (10.8)] compared to infants receiving ferric [17.6 (14.50)] and liposomal iron [15.4 (12.1)] (P < 0.001). Mean (SD) hemoglobin levels (g/dL) were significantly higher in the ferrous group [12.4 (0.8)] compared to ferric [11.9 (1.1)] and liposomal iron group [12.0 (1.1)]; P =0.008. Multiple regression analysis showed that ferrous group was associated with a lower risk of iron deficiency [OR (95% CI) 0.04 (0.01–0.15), P < 0.001]. Conclusion: Ferrous iron demonstrated superior efficacy compared to ferric and liposomal iron. Further studies are needed to establish alternative iron preprations in children. [ABSTRACT FROM AUTHOR]

The growing challenges of reducing exhaust emissions and improved fuel economy has triggered automotive engineers to design and manufacture engine parts with superior mechanical properties and dimensional accuracies. Valve guides are cylindrical structures supporting inlet valve and exhaust valve stems during operation. Conventionally made of grey cast iron material, valve guide suffers from severe wear losses leading to loss of fuel and increased emissions due to improper valve stem seating. Here, the synthesis of a novel ferrous powder metallurgy composite is presented and wear characteristics have been studied at varying loads of 30 N, 40 N and 50 N and varying sliding speeds of 0.5 m/s, 1 m/s and 2 m/s under lubricated conditions. The samples have undergone nitriding heat treatment at 1150 °C to improve surface hardness to 700 Hv. The samples have shown negative wear rates due to high hardness and capillary action of lubricating oil and exhibited stable friction coefficient values. This has been attributed to the formation of hard phases Fe2N, Fe3N, and Fe4N and Fe(Mn)3C and twinning-induced plastic compounds like (Fe24Mn) 0.08 as evident from XRD analysis. The morphological analysis of worn out samples was done with SEM Coupled with EDS and it showed micro-cutting, Ploughing, and delamination as main wear phenomenon.

Copyright of Scientific Journal of Agricultural Sciences (SJAS) is the property of Beni Suef University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The accurate determination of uranium content in geological samples is extremely important for the exploration and development of uranium resources. In this study, based on titration method for the determination of uranium content of the nuclear industry standard test, the pretreatment process such as sample dissolution, sample dissolution reagent and test method has been improved according to the characteristics of geological samples. The results showed that the sample was moistened with water before acid treatment, and the dissolving vessel was adjusted from 100 mL beaker to 150 mL triangle flask, which basically avoided the problem of sputtering during the boiling process. The amount of phosphoric acid added in the sample dissolution reagent was increased to ensure that the ferrous could completely reduce the hexavalent uranium in the sample at the appropriate phosphoric acid concentration, and the low measurement result caused by the low phosphoric acid concentration is avoided. In the test, the amount of reducing agent ferrous sulfate is changed to 1 mL, and the amount of sodium nitrite was changed to 3–4 drops, which improved the sensitivity of titration endpoint and realized clear determination of titration end point. The RSD of the improved test method is better than 2.5%, and the standard recovery is between 99 and 102%. The results are accurate and reliable, can meet the needs of scientific research and production. It can provide technical support for uranium exploration and natural uranium production. [ABSTRACT FROM AUTHOR]

Introduction: The performance functionality efficacy of the engine’s valve train assembly is considerably affected by the valve guide. Material selection is impacted by the prolonged operational lifespan of engines, which favours casting and machining materials such as cast iron. The intent of this study is to examine the dry sliding characteristics of GG25 cast iron with copper additives. Discovering the ways in which variations in load and sliding velocity impact wear characteristics is of paramount significance. Methods: The research entailed the examination of wear characteristics across various environmental conditions. Loads were varied at 30 N, 40 N, and 50 N while maintaining a 1 m/s velocity constant. In the same manner, sliding velocities of 0.5 m/s, 1 m/s, and 2 m/s were varied while a constant load of 30 N was maintained. Experimental techniques were carried out at ambient temperature. Throughout the investigations, frictional forces and the coefficient of friction were also determined. The wear mechanisms of samples that had become deteriorated or worn-out were examined by employing a scanning electron microscope when combined with EDX analysis. Results: A rise in the normal load from 30 N to 40 N led to a twofold rise in wear losses, measuring 417 microns as compared with 222 microns previously. The range of wear losses observed at moderate speeds (0.5 m/s–1 m/s) was 133–222 microns. Conversely, the maximum wear loss observed was 1,226 microns at elevated sliding velocities of 2 m/s, in contrast to 617 microns at higher normal loads of 50 N. Additionally, the research discovered that normal load is more pronounced when both loading and speed are moderate, whereas sliding speed becomes more substantial when both are raised, culminating to higher wear losses. Discussions: In summary, the research highlights the considerable effect that normal load and sliding speed have on the prevalence of wear losses. In conditions of moderate loading and velocity, the influence of normal load is more significant. However, as sliding accelerates, it becomes the predominant factor. An analysis of frictional forces as well as the coefficient of friction indicated that under loading conditions of 30 N–50 N, the friction coefficient raised from 0.238 to 0.43. The wear mechanisms, as discerned via scanning electron microscopy and EDX analysis, underscored the considerable impact of increased sliding velocity on wear loss in comparison to conditions of higher loading. [ABSTRACT FROM AUTHOR]

Introduction: The performance functionality efficacy of the engine’s valve train assembly is considerably affected by the valve guide. Material selection is impacted by the prolonged operational lifespan of engines, which favours casting and machining materials such as cast iron. The intent of this study is to examine the dry sliding characteristics of GG25 cast iron with copper additives. Discovering the ways in which variations in load and sliding velocity impact wear characteristics is of paramount significance.Methods: The research entailed the examination of wear characteristics across various environmental conditions. Loads were varied at 30 N, 40 N, and 50 N while maintaining a 1 m/s velocity constant. In the same manner, sliding velocities of 0.5 m/s, 1 m/s, and 2 m/s were varied while a constant load of 30 N was maintained. Experimental techniques were carried out at ambient temperature. Throughout the investigations, frictional forces and the coefficient of friction were also determined. The wear mechanisms of samples that had become deteriorated or worn-out were examined by employing a scanning electron microscope when combined with EDX analysis.Results: A rise in the normal load from 30 N to 40 N led to a twofold rise in wear losses, measuring 417 microns as compared with 222 microns previously. The range of wear losses observed at moderate speeds (0.5 m/s–1 m/s) was 133–222 microns. Conversely, the maximum wear loss observed was 1,226 microns at elevated sliding velocities of 2 m/s, in contrast to 617 microns at higher normal loads of 50 N. Additionally, the research discovered that normal load is more pronounced when both loading and speed are moderate, whereas sliding speed becomes more substantial when both are raised, culminating to higher wear losses.Discussions: In summary, the research highlights the considerable effect that normal load and sliding speed have on the prevalence of wear losses. In conditions of moderate loading and velocity, the influence of normal load is more significant. However, as sliding accelerates, it becomes the predominant factor. An analysis of frictional forces as well as the coefficient of friction indicated that under loading conditions of 30 N–50 N, the friction coefficient raised from 0.238 to 0.43. The wear mechanisms, as discerned via scanning electron microscopy and EDX analysis, underscored the considerable impact of increased sliding velocity on wear loss in comparison to conditions of higher loading.

Abstract Background Biofilms play a role in recalcitrance and treatability of bacterial infections, but majority of known antibiotic resistance mechanisms are biofilm-independent. Biofilms of Pseudomonas aeruginosa, especially in cystic fibrosis patients infected with the alginate producing strains in their lungs, are hard to treat. Changes in growth-related bacterial metabolism in biofilm affect their antibiotic recalcitrance which could be considered for new therapies designed based on these changes. In this study, effects of nitrate, arginine, and ferrous were investigated on antibiotic recalcitrance in alginate-encapsulated P. aeruginosa strains isolated from cystic fibrosis patients in the presence of amikacin, tobramycin, and ciprofloxacin. Also, expression of an efflux pump gene, mexY, was analyzed in selected strains in the presence of amikacin and ferrous. Methods Clinical P. aeruginosa strains were isolated from cystic fibrosis patients and minimum inhibitory concentration of amikacin, tobramycin, and ciprofloxacin was determined against all the strains. For each antibiotic, a susceptible and a resistant or an intermediate-resistant strain were selected, encapsulated into alginate beads, and subjected to minimal biofilm eradication concentration (MBEC) test. After determining MBECs, sub-MBEC concentrations (antibiotics at concentrations one level below the determined MBEC) for each antibiotic were selected and used to study the effects of nitrate, arginine, and ferrous on antibiotic recalcitrance of encapsulated strains. Effects of ferrous and amikacin on expression of the efflux pump gene, mexY, was studied on amikacin sensitive and intermediate-resistant strains. One-way ANOVA and t test were used as the statistical tests. Results According to the results, the supplements had a dose-related effect on decreasing the number of viable cells; maximal effect was noted with ferrous, as ferrous supplementation significantly increased biofilm susceptibility to both ciprofloxacin and amikacin in all strains, and to tobramycin in a resistant strain. Also, treating an amikacin-intermediate strain with amikacin increased the expression of mexY gene, which has a role in P. aeruginosa antibiotic recalcitrance, while treating the same strain with ferrous and amikacin significantly decreased the expression of mexY gene, which was a promising result. Conclusions Our results support the possibility of using ferrous and arginine as an adjuvant to enhance the efficacy of conventional antimicrobial therapy of P. aeruginosa infections.

Naturally occurring Fe(III) films with rainbow reflection iridescence have been observed floating on the water surface of various spots covered with shallow water (e.g., edges of wetlands and creeks, standing water over soils). This natural phenomenon has become a scenic attraction and stimulated much curiosity. We pursued an experimental inquiry aimed at probing this interesting, curious natural wonder. As the first critical task, floating Fe(III) films were successfully generated in an assessable, controllable setting in our laboratory. This enabled us to establish this phenomenon reproducibly under controlled conditions and characterize the phenomenon over the entire span of the formation and transformation of the Fe(III) films. Our film generation method requires a few things: fresh soil (source for Fe(III) and microbes), glucose (energy source), and water in a container. The floating Fe(III) films as observed in the field occurred in ~1–3 day(s) on the water surface of the inundated soil mixed with the sugar. The Fe(III) films then grew from initial very thin, colorless, somewhat transparent films with rainbow reflection iridescence to colored thicker films and then to orange/orange-red/red crusts over the time. A comprehensive mechanistic picture was formulated to depict the formation of the Fe(III) films. Several sequential processes are operative. First, the Fe(III) (oxides, oxyhydroxides) in the soil is reduced to Fe(II) by the Fe(III)-reducing microbes during their anerobic respiration with Fe(III) as the electron (e−) acceptor after depletion of dissolved O2 in the water as a result of aerobic microbial respiration with O2 as the e− acceptor. The Fe(II), being soluble, then diffuses to the water surface where it is oxidized to Fe(III). Subsequently, the Fe(III) hydrolyzes and various Fe(III) hydrolysis products polymerize to stabilize. A polymeric model was created to account for the Fe(III) film transformation. The Fe(III) films are considered to transform from the dimers and trimers and linear polymers of Fe(OH)3 to Fe(III) polymer sheets (e.g., Fe(OH)3, FeOOH), to 3D Fe(III) polymers, and eventually to Fe2O3 colloid particles. This floating Fe(III) film phenomenon boasts an environmental chemical drama of redox cycling of Fe(III)/Fe(II) at soil/water and water/air interfaces coupled with Fe(II) transport from the inundated soil to the water surface followed by ultimate mineralization of the Fe(III) polymers. Our Fe(III) film generation method can be readily scaled up to supply Fe(III) films of rich varieties in thickness, size, morphology, and structure over the entire span of various stages of their formation and transformation as desired for various uses. This setup offers a platform needed for further controlled studies on the kinetics, mechanism, and process of abiotic and biotic nature involved in the Fe(III) film phenomenon and for exploration of versatile roles of the Fe(III) films as nanofilms in Fe(III)/Fe(II)-surface catalyzed chemical and photochemical reactions involving various natural and synthetic compounds.

Background: Biofilms play a role in recalcitrance and treatability of bacterial infections, but majority of known antibiotic resistance mechanisms are biofilm-independent. Biofilms of Pseudomonas aeruginosa, especially in cystic fibrosis patients infected with the alginate producing strains in their lungs, are hard to treat. Changes in growth-related bacterial metabolism in biofilm affect their antibiotic recalcitrance which could be considered for new therapies designed based on these changes. In this study, effects of nitrate, arginine, and ferrous were investigated on antibiotic recalcitrance in alginate-encapsulated P. aeruginosa strains isolated from cystic fibrosis patients in the presence of amikacin, tobramycin, and ciprofloxacin. Also, expression of an efflux pump gene, mexY, was analyzed in selected strains in the presence of amikacin and ferrous. Methods: Clinical P. aeruginosa strains were isolated from cystic fibrosis patients and minimum inhibitory concentration of amikacin, tobramycin, and ciprofloxacin was determined against all the strains. For each antibiotic, a susceptible and a resistant or an intermediate-resistant strain were selected, encapsulated into alginate beads, and subjected to minimal biofilm eradication concentration (MBEC) test. After determining MBECs, sub-MBEC concentrations (antibiotics at concentrations one level below the determined MBEC) for each antibiotic were selected and used to study the effects of nitrate, arginine, and ferrous on antibiotic recalcitrance of encapsulated strains. Effects of ferrous and amikacin on expression of the efflux pump gene, mexY, was studied on amikacin sensitive and intermediate-resistant strains. One-way ANOVA and t test were used as the statistical tests. Results: According to the results, the supplements had a dose-related effect on decreasing the number of viable cells; maximal effect was noted with ferrous, as ferrous supplementation significantly increased biofilm susceptibility to both ciprofloxacin and amikacin in all strains, and to tobramycin in a resistant strain. Also, treating an amikacin-intermediate strain with amikacin increased the expression of mexY gene, which has a role in P. aeruginosa antibiotic recalcitrance, while treating the same strain with ferrous and amikacin significantly decreased the expression of mexY gene, which was a promising result. Conclusions: Our results support the possibility of using ferrous and arginine as an adjuvant to enhance the efficacy of conventional antimicrobial therapy of P. aeruginosa infections. [ABSTRACT FROM AUTHOR]

Highly efficient azo-day quinazolinone derivatives carrying a π bond and OH electron donor groups have been designed, synthesized, and evaluated as colorimetric chemosensors for detecting metal ions in biological and environmental samples, which was further supported by the DFT studies and UV–vis titration experiment. The 3-amino-2-styrylquinazolin-4(3H)-one (1) was directed to react with phenols during a diazotization type reaction to form a series of azo-day 3-(diazenyl)-2-(styryl)quinazolin-4(3H)-one (4a-e), which could not only have been confirmed by FTIR, H1NMR, C13NMR, Ms and elemental analysis but could also be easily used for the detection of metal ions. Compound 4c exhibited a rapid qualitative and quantitative method for the detection of CoII at λ max (582 nm) and FeII at λ max (566 nm) in an aqueous solution. The current study introduces a facile, low cost, more specific and selective chemosensor for detecting trace amounts of cobalt and ferrous ions.

Incense sticks ash is one of the most unexplored by-products generated at religious places and houses obtained after the combustion of incense sticks. Every year, tonnes of incense sticks ash is produced at religious places in India which are disposed of into the rivers and water bodies. The presence of heavy metals and high content of alkali metals challenges a potential threat to the living organism after the disposal in the river. The leaching of heavy metals and alkali metals may lead to water pollution. Besides this, incense sticks also have a high amount of calcium, silica, alumina, and ferrous along with traces of rutile and other oxides either in crystalline or amorphous phases. The incense sticks ash, heavy metals, and alkali metals can be extracted by water, mineral acids, and alkali. Ferrous can be extracted by magnetic separation, while calcium by HCl, alumina by sulfuric acid treatment, and silica by strong hydroxides like NaOH. The recovery of such elements by using acids and bases will eliminate their toxic heavy metals at the same time recovering major value-added minerals from it. Here, in the present research work, the effect on the elemental composition, morphology, crystallinity, and size of incense sticks ash particles was observed by extracting ferrous, followed by extraction of calcium by HCl and alumina by H2SO4 at 90–95 °C for 90 min. The final residue was treated with 4 M NaOH, in order to extract leachable silica at 90 °C for 90 min along with continuous stirring. The transformation of various minerals phases and microstructures of incense sticks ash (ISA) and other residues during ferrous, extraction, calcium, and alumina and silica extraction was studied using Fourier transform infrared (FTIR), dynamic light scattering (DLS), X-ray fluorescence (XRF), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and inductively coupled plasma-optical emission spectroscopy (ICP-OES). DLS was used for analyzing the size during the experiments while FTIR helped in the confirmation of the formation of new products during the treatments. From the various instrumental analyses, it was found that the toxic metals present in the initial incense sticks ash got eliminated. Besides this, the major alkali metals, i.e., Ca and Mg, got reduced during these successive treatments. Initially, there were mainly irregular shaped, micron-sized particles that were dominant in the incense sticks ash particles. Besides this, there were plenty of carbon particles left unburned during combustion. In the final residue, nanosized flowers shaped along with cuboidal micron-sized particles were dominant. present in If, such sequential techniques will be applied by the industries based on recycling of incense sticks ash, then not only the solid waste pollution will be reduced but also numerous value-added minerals like ferrous, silica, alumina calcium oxides and carbonates can be recovered from such waste. The value-added minerals could act as an economical and sustainable source of adsorbent for wastewater treatment in future. [ABSTRACT FROM AUTHOR]

Ferrate fortified with ferrous iron can effectively improve the degradation of tetracycline (TC) in the coagulation process. Optimizing experiment conditions is investigated in the ferrate and ferrate-ferrous system. TC removing was up to 85% when the molar ratio of ferrate to TC was 2.5:1 under initial pH 4–9. Ferrate-ferrous performance is better than only ferrate or ferrous, and the morphology and composition of flocs formed by the ferrous and ferrate-ferrous systems are investigated. The initial pH has an influence on the coagulation process, whether in the ferrous or ferrate-ferrous system. The stability of flocs created by the ferrate-ferrous system under alkaline conditions was better than that under acidic conditions. Nevertheless, flocs formed by ferrous under acidic conditions were better than that under alkaline conditions. The flocs' stability is related to their composition and structure. The proportion of α-FeOOH formed by Fe(VI)–Fe(II) was approximately between 26% and 37.3%, and the proportion of γ-FeOOH was 63~74%. The knowledge obtained in this research enhances the flocculation effect of ferrate and its ability for sustainable oxidative degradation of pollutants. [ABSTRACT FROM AUTHOR]

Purpose: Giant leucaena is a tropical tree-legume that thrives in alkaline and calcareous soils. It contains large amounts of mimosine, the physiological role of which is not well understood. The goals of this study were to determine i) if mimosine is released by giant leucaena into the rhizosphere ii) if mimosine enhances solubility of Fe present in various forms in alkaline soil, and iii) if mimosine enhances transition metal uptake in giant leucaena. Methods: Mimosine in the extracts of rhizosphere soil and root exudates was analyzed by high performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS) to determine if it is released by giant leucaena. Iron concentration in tissue and aqueous samples was determined by ICP-OES analysis. Results: Mimosine was detected in both the rhizosphere eluates and root exudates. Mimosine added to samples of goethite, hematite and FeCl3 increased Fe solubility in water. Giant leucaena plants grown in alkaline soils and supplied with mimosine had higher levels of chlorophyll, Fe and Mn than the control plants. Conclusion: Mimosine is released by giant leucaena roots into the rhizosphere, where it interacts with Fe. Mimosine enhances solubility of insoluble Fe-oxides and prevents conversion of ferric Fe to insoluble oxides at an alkaline pH. Mimosine enhances Fe and Mn uptake in plants growing in alkaline soil conditions. [ABSTRACT FROM AUTHOR]

Experiments for simultaneous elimination and detoxification of microgram level of As(Ⅲ) in the presence of micromolar H2O2 and Fe(Ⅱ) which are frequently encountered in natural water were conducted. The results showed that the molar ratio of oxidant to As(III) plays important role in As(III) oxidation under the experimental conditions. The extent of As(Ⅲ) oxidation with single H2O2 or Fe(Ⅱ) ranged from 7.9 % to 60.3 % and 22.2–46.6 %, respectively. Treatments with H2O2/As(Ⅲ) molar ratios in the range 150: 1–750: 1 or Fe(Ⅱ)/As(Ⅲ) molar ratios in the range 37.5: 1–375: 1 were more favor for As(Ⅲ) oxidation respectively, and increasing oxidant concentration did not result in complete As(Ⅲ) oxidation. As(Ⅲ) was completely oxidized and eliminated following the precipitation of ferric hydroxides in 5 reaction minutes when H2O2 and Fe(Ⅱ) coexisted in the reaction system. The interface characterization for the reacted precipitates after the experiment were conducted by using a high-resolution field emission scanning electron microscopy (SEM) coupled with an EX-350 energy dispersive X-ray spectrometer (EDX) and X-ray photoelectron spectroscopy (XPS), respectively. The results showed that As(Ⅴ) was the merely arsenic species and As oxide primary situated in the subsurface layer of the reacted precipitates, whereas Fe was more concentrated in the outermost surface layer. Our research showed that H2O2 and Fe(Ⅱ) at natural level may exert significant influence on arsenic mobilization in natural water. Considering the much more toxic of As(Ⅲ) than that of As(Ⅴ), the research also provide us an environmental friendly choice in the elimination and detoxification of microgram As(Ⅲ) in drinking water.

Coal fly ash (CFA) is one of the major pollutants around the whole world. At the same time, incense stick ash (ISA) is another waste that is generated in huge amounts in Southeast Asia. Both of these wastes are rich in different types of minerals; for instance, CFA is rich in alumina, silica, and ferrous, while incense sticks ash is rich in calcium and silica. ISA has intermediate to trace amounts of ferrous, alumina, and magnesium. The addition of alkali-rich materials with high Al and Si-containing CFA helps in the formation of zeolites or geopolymers. So, in the current research work, the authors have prepared a CFA: ISA mixture in the ratio of 1:1, followed by mixing them with NaOH, CaOH2, and KOH in a dry state in a crucible. Further, all these mixtures were then calcined at 600 °C for six hours in a muffle furnace. Further, the developed products were analyzed by various sophisticated instruments for detailed information. Finally, the developed material's potential was assessed for the remediation of malachite green from the aqueous solution by batch adsorption study. The developed adsorbents efficiently removed the dye from the aqueous solutions within one hour. The kinetic study revealed that the dye removal followed a pseudo-second-order reaction. Finally, the developed material was also assessed for its suitability as an adsorbent by observing the effect of leaching of potassium, aluminum, and silica from the adsorbent surface into the water systems. Such approaches will solve the problem of solid waste disposal arising from both the ashes. [ABSTRACT FROM AUTHOR]

Factors affecting the degradation of Acid Orange 7 (AO7) were evaluated and optimized when ferrous was used to catalyze percarbonate in the present study. The optimized conditions included the initial pH values ranging from 3 to 11 for AO7 solution, the initial level of AO7, sodium percarbonate (SPC), and Fe2+. Some ions and natural organic materials, which commonly exist in natural water, were also tested to evaluate their potential impacts on the degradation of AO7. The degradation efficiency of AO7 was up to 95% under the optimized test conditions, where the ferrous/percarbonate/AO7 molar ratio was 15/10/1 in the 0.285 mmol/l AO7 aqueous solution. The presence of Cl−, SO42−, NO3−, Na+, and Mg2+ did not affect the removal of AO7. The addition of HCO3− significantly inhibited its removal, even when the concentration of HCO3− was low to 0.6 mmol/l. A slight inhibition effect was observed when the added concentration of humic acid ranged from 0.5 to 5 mg/l, whereas the residue of AO7 was significantly enhanced when the level of humic acid was continually increased from 50 to 100 mg/l. Hydroxyl radicals (•OH) were the main reactive intermediates controlling the oxidation of AO7 in the present Fe2+/SPC system. The produced intermediates through the degradation of AO7 were identified to include 2‐coumaranone, 2‐naphthol, phthalic acid, phthalimide, N‐methylnaphthylamine, and 2‐methylphenol. The proposed degradation pathways are consistent with the radical formation and the identified intermediates. Practitioner Points: The ferrous/percarbonate system can remove 95% of AO7 under the optimized conditions.AO7 removal was inhibited by adding HCO3− and humic acid, but not affected by Cl−, SO42−, NO3−, Na+, and Mg2+.Hydroxylation, ring opening, and mineralization driven by the generated hydroxyl radicals were derived as the major processes for degrading AO7. [ABSTRACT FROM AUTHOR]

[Display omitted] • SOM significantly inhibited TCS and NPS degradation in the Fe2+/PS system. • Molecular properties of the three PPCPs determined their reactivity with oxidants. • SO 4 •− and 1O 2 played major roles in TCS and NPS degradation in different soils. • Soil surface functional groups possibly consumed •OH and 1O 2 , and generated SO 4 •−. • Soil types affected the degradation pathways of TCS and NPS in different soils. Pharmaceuticals and personal care products (PPCPs) are widely used worldwide and cause potential soil pollution. Fe2+-activated persulfate (PS) processes (Fe-PAPs) are promising techniques for soil remediation. However, a knowledge gap exists in the mechanistic insights into the dominant factors affecting the degradation of different PPCPs in varied soil types. This study systematically investigated the roles of soil components and pollutant properties in the degradation of three PPCPs (triclosan (TCS), triclocarban (TCC), and naproxen (NPS)) in the nine soils in the Fe2+/PS system. The degradation efficiencies of TCS and NPS ranged from 10.92 % to 91.62 % and 46.59 % to 99.81 %, respectively, whereas nearly no degradation was observed for TCC. PPCPs with high water solubility, high energies of the highest occupied molecular orbital (E HOMO), low p K a values, low energy gap (ΔE), or low vertical ionization potential (VIP) were more favorable for degradation. XPS analysis suggested that aliphatic carbon (Ali–C–C(H)), ether or alcohol carbon (C–O), and aldehyde or ketonic carbon (C O) on SOM significantly inhibited TCS degradation. The results of ROS quenching experiments showed that SO 4 •− and 1O 2 played major roles in TCS and NPS degradation in the six soils, with the relative contributions ranged from 24.82 % to 99.14 % and 0.15 % to 73.40 %, respectively. The interaction between soil components, active species, and pollutants resulted in the distinct intermediates of TCS and NPS in different soils. Our findings provide in-depth insights into the role of soil composition and pollutant properties on the remediation of PPCP-contaminated soils in Fe-PAPs. [ABSTRACT FROM AUTHOR]

This paper is devoted to the memory of Professor Ljubomir Nedeljkovic (1933-2020), Head of the Department of Iron and Steel Metallurgy University of Belgrade, Serbia. Assessment of the melt quality is one of the most important casting process parameters, which allowed sound production of intricated cast parts. At the present time, various devices have been applied at foundry floors to control melt quality. Thermal analysis is one of them, widely used for melt quality control in ferrous and non-ferrous casting plants. During solidification, metal and alloys released latent heat, which magnitude is dependent on the type of phases that form during the solidification process. Plotting temperature versus time data during solidification provides useful information related to the actual solidification process. The applied technique is called thermal analysis, whereas the cooling curve is the name of such a plot. The main aim of this paper is to give a short overview of the present thermal analysis application in various foundries and to indicate the future potential use of this technique.

ABSTRACT Pseudomonas aeruginosa is an opportunistic pathogen that has been declared by the World Health Organization as a “priority 1 critical pathogen” needing immediate new strategies for chemotherapy. During infection, P. aeruginosa uses redundant mechanisms to acquire ferric, heme (Hm), or ferrous iron from the host to survive and colonize. Significant efforts have been undertaken to develop siderophore blockers to inhibit ferric iron acquisition by P. aeruginosa, but there is a lack of inhibitors that can block Hm or ferrous iron acquisition by P. aeruginosa. We developed and employed a targeted high-throughput screen (HTS) and identified a molecule(s) that can specifically inhibit the Hm and ferrous iron acquisition systems of P. aeruginosa. Our targeted approach relies on screening a small-molecule library against P. aeruginosa under three growth conditions, where the only variable was the iron source (ferric, Hm, or ferrous iron). Each condition served as a counterscreen for the other, and we identified molecules that inhibit the growth of P. aeruginosa in the presence of only Hm or ferrous iron. Our data indicate that econazole, bithionate, and raloxifene inhibit the growth of P. aeruginosa in the presence of Hm and that oxyquinoline inhibits the growth of P. aeruginosa in the presence of ferrous iron. These iron-specific inhibitors do not interfere with the activity of meropenem, a commercial antipseudomonal, and can also increase meropenem activity. In conclusion, we present a proof of concept of a successful targeted conditional screening method by which we can identify specific iron acquisition inhibitors. This approach is highly adaptable and can easily be extended to any other pathogen. IMPORTANCE Since acquiring iron is paramount to P. aeruginosa’s survival and colonization in the human host, developing novel strategies to block the access of P. aeruginosa to host iron will allow us to starve it of an essential nutrient. P. aeruginosa uses siderophore, heme, or ferrous iron uptake systems to acquire iron in the human host. We have developed a novel approach through which we can directly identify molecules that can prevent P. aeruginosa from utilizing heme or ferrous iron. This approach overcomes the need for the in silico design of molecules and identifies structurally diverse biologically active inhibitor molecules. This screening approach is adaptable and can be extended to any pathogen. Since Gram-negative pathogens share many similarities in iron acquisition at both the mechanistic and molecular levels, our screening approach presents a significant opportunity to develop novel broad-spectrum iron acquisition inhibitors of Gram-negative pathogens.

This study was conducted to evaluate effects of organic fertilizers on micronutrients status of soil and yield of sesame. Research was performed in split-plot design based on a randomized complete block design with three replications. The experimental treatments included animal manure as main factor at three levels (0, 10, and 20 t ha−1) and application of green manures as sub factor at four levels (no green manure, Berseem clover, Fenugreek, and Vicia villosa). The results showed by application of animal manure, copper (Cu), zinc (Zn), manganese (Mn), and ferrous (Fe) contents in the treatment of 20 t ha−1 of animal manure were about 27, 22, 7.5, and 6% higher than the control treatment, respectively. The soil analysis showed in the post-harvesting stage of sesame 2.7% Cu and 29% Zn were stored in the soil. While the amounts of Fe 11% and Mn 71% in the soil were less than pre-planting of sesame. In general, fenugreek green manure application increased the amounts of micronutrients of soil more than the other green manures and animal manure individually. The highest total dry weight (10720.0 kg ha−1), grain yield (1929.4 kg ha−1) and oil yield (946.8 kg ha−1) were observed in the 20 t ha−1 of animal manure and Fenugreek of green manure treatments, which were about 44, 52 and 50% higher than the non-application of animal and green manures treatments, respectively. In general, the application of organic manures increased sesame yield by improving the physico-chemical properties and the amount of soil micronutrients. [ABSTRACT FROM AUTHOR]

Copyright of Advanced Engineering Science / Gongcheng Kexue Yu Jishu is the property of Advanced Engineering Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fly ash or coal fly ash causes major global pollution in the form of solid waste and is classified as a “hazardous waste”, which is a by-product of thermal power plants produced during electricity production. Si, Al, Fe Ca, and Mg alone form more than 85% of the chemical compounds and glasses of most fly ashes. Fly ash has a chemical composition of 70–90%, as well as glasses of ferrous, alumina, silica, and CaO. Therefore, fly ash could act as a reliable and alternative source for ferrous, alumina, and silica. The ferrous fractions can be recovered by a simple magnetic separation method, while alumina and silica can be extracted by chemical or biological approaches. Alumina extraction is possible using both alkali- and acid-based methods, while silica is extracted by strong alkali, such as NaOH. Chemical extraction has a higher yield than the biological approaches, but the bio-based approaches are more environmentally friendly. Fly ash can also be used for the synthesis of zeolites by NaOH treatment of variable types, as fly ash is rich in alumino-silicates. The present review work deals with the recent advances in the field of the recovery and synthesis of ferrous, alumina, and silica micro and nanoparticles from fly ash.

Coal fly ash (CFA) is one of the major pollutants around the whole world. At the same time, incense stick ash (ISA) is another waste that is generated in huge amounts in Southeast Asia. Both of these wastes are rich in different types of minerals; for instance, CFA is rich in alumina, silica, and ferrous, while incense sticks ash is rich in calcium and silica. ISA has intermediate to trace amounts of ferrous, alumina, and magnesium. The addition of alkali-rich materials with high Al and Si-containing CFA helps in the formation of zeolites or geopolymers. So, in the current research work, the authors have prepared a CFA: ISA mixture in the ratio of 1:1, followed by mixing them with NaOH, CaOH2, and KOH in a dry state in a crucible. Further, all these mixtures were then calcined at 600 °C for six hours in a muffle furnace. Further, the developed products were analyzed by various sophisticated instruments for detailed information. Finally, the developed material’s potential was assessed for the remediation of malachite green from the aqueous solution by batch adsorption study. The developed adsorbents efficiently removed the dye from the aqueous solutions within one hour. The kinetic study revealed that the dye removal followed a pseudo-second-order reaction. Finally, the developed material was also assessed for its suitability as an adsorbent by observing the effect of leaching of potassium, aluminum, and silica from the adsorbent surface into the water systems. Such approaches will solve the problem of solid waste disposal arising from both the ashes.

[Display omitted] • Glycerol conversion to 1,3-propanediol has been examined with K. pneumonia L17. • Zero-valent iron (ZVI) was used as an electron donor for glycerol conversion. • ZVI increased the level of 1,3-PDO by 2.1 fold compared to the control. • The change in metabolic flux with ZVI was analyzed using the MetaFluxNet program. 1,3-PDO (1,3-propanediol) is a high value-added platform chemical used widely in adhesives, laminates, and food additives. For the efficient production of 1,3-PDO, the sustainable and non-toxic regeneration of NADH is of great importance. ZVI (Zero-Valent Iron) can provide a reducing equivalent for 1,3-PDO synthesis from glycerol as an electron donor. Klebsiella pneumoniae has a 1,3-PDO conversion pathway from glycerol and has been studied as an electrochemically active strain that can exchange respiratory electrons through the cell membrane. In this study, 1,3-PDO was produced using an electrochemically active strain, K. pneumoniae L17, and ZVI as an electron donor. The production of 1,3-PDO with ZVI increased significantly to 24.2 ± 1.3 mM compared to the control (12.0 ± 0.1 mM). These results suggest that an external reducing agent, such as ZVI, can regulate the bioconversion of K. pneumoniae L17, and improve the conversion of glycerol to value-added platform chemicals. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China Normal University (Natural Science Edition) / Huanan Shifan Daxue Xuebao (Ziran Kexue Ban) is the property of Journal of South China Normal University (Natural Science Edition) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ferrous (Fe (II)) plays a key role in the production or consumption of N 2 O through biochemical pathways in paddy soil. Drying-wetting alternations can affect Fe cycling and the associated N 2 O emissions, however, the underlying microbial mechanisms remain largely unknown, particularly in plant systems with the presence of roots. In this study, a laboratory experiment with four Fe (II) levels (0, 50, 150, and 300 mg Fe (II) kg−1 dry soil) was conducted to investigate the response of N 2 O emission and denitrifying genes to iron (II) supplement in root zone and bulk region during wetting-drying cycles in paddy soils. The results indicated that supplemented Fe (II) led to a reduction in soil N 2 O emissions, predominantly observed during the drying phase. The bulk soil exhibited higher N 2 O fluxes compared to root zone. However, the decrease in cumulative N 2 O (cumul-N 2 O) by Fe (II) was significantly greater in bulk region than in root-affected soil (P < 0.001), registering 85–91 % reduction for soils amended with low to medium rates (50 and 150 mg Fe (II) kg−1 dry soil) throughout the experiment. This might be attributed to the more sensitive response of N 2 O reductase (nosZ gene) to low or medium Fe (II) supplementation in bulk soil than in root zone. The highest Fe (II) addition (300 mg Fe (II) kg−1 dry soil) showed a negative impact on nosZ -containing gene during initial flooding phase, resulting in the lower reduction rate (40 %) in cumulative N 2 O emission from bulk soil. Cross-correlation analysis showed that the changes of nosZ- containing genes in root zone occurred before variations of cumulative N 2 O data, indicating that compared to bulk soil, root zone soil exhibited a more pronounced of N 2 O consumption capability, especially after addition of ferrous. In summary, judicious Fe (II) application into soil promotes N 2 O reduction during wetting-drying alternation. The response of nosZ abundance to Fe (II) supplementation is likely the pivotal microbial factor influencing N 2 O emission reduction during wetting-drying alternation in paddy soil. [Display omitted] • Addition of Fe(II) into paddy soil reduced N 2 O emission during wetting-drying alternation. • Supplemented Fe(II) significantly increased nosZ gene from paddy soil during drying. • The root zone in rice-planted paddy soil might have the stronger capacity of N 2 O consumption. • Relations between N 2 O emission and abundance of denitrifying genes often existed with time lags. [ABSTRACT FROM AUTHOR]

• The combination of Fe2+/Fe3+ sulfate was used as selective depressant for the flotation separation of fluorite and calcite. • Ferrous and ferric species were in-situ generated on calcite surface to hinder the adsorption of NaOL. • Fluorite concentrate with CaF 2 grade of 80.29 % and recovery of 90.79 % was obtained using 1:1 mixed minerals. It is known that the flotation separation of fluorite/calcite is extremely difficult because of their similar surface features. In this research, the combination of FeSO 4 ·7H 2 O and Fe 2 (SO 4) 3 (FF) as depressant for possible flotation separation of calcite/fluorite was systematically investigated, with sodium oleate (NaOL) as collector. Besides large gap between mono-mineral flotation results of fluorite and calcite, even for 1:1 mixed sample, CaF 2 grade of 80.29 % and CaF 2 recovery of 90.79 % of fluorite concentrate can be achieved with FeSO 4 ·7H 2 O (300 mg/L) and Fe 2 (SO 4) 3 (150 mg/L) used as combined depressant and NaOL (40 mg/L) as collector at pH = 6. In addition to the quantitative micro-flotation results on mono-mineral and artificially mixed sample, SEM-EDS, contact angle measurement, zeta potential measurement, FTIR and XPS analyses, as well as collector adsorption experiment, were carried out to clarify the selective inhibition mechanism. Characterizations confirmed that, under interaction with iron sulfates (FF), ferrous hydroxide, ferric hydroxide, hydroxyl iron oxide and green rust were in-suit generated on calcite surface due to the presence of the hydrolysis of OH− and CO 3 2− on calcite surface, while such Fe-related components were barely discernible on fluorite surface. These different adsorption features for Fe (II) and Fe (III) species on mineral surfaces exactly hindered the complexation of NaOL on calcite surface, while maintained the adsorption of collector on fluorite surface, thereby to realize the selective separation of fluorite from calcite. [ABSTRACT FROM AUTHOR]

Enhancement of sludge dewaterability is key for sludge management and disposal of wastewater treatment plants (WWTP). In this study, the Fe2+-peroxymonosulfate (PMS) conditioning approach was first used to oxidize the primary sludge from the primary sedimentation tank of a full scale WWTP. The combination of Fe2+ (0.05–0.5 g/g TSS) and PMS (0.05–0.5 g/g TSS) could significantly improve the dewaterability of primary sludge. The optimal addition amount of Fe2+ and PMS was 0.1 g/g TSS and 0.25 g/g TSS, respectively, under which the capillary suction time (CST) and specific resistance to filtration (SRF) of the sludge was reduced by 79% and 95%. The physicochemical properties (particle size, zeta potential, EPS composition) of the primary sludge before and after oxidative conditioning were measured. Results showed that sulfate radicals generated from Fe2+-PMS system effectively reduced organic matter in different EPS fractions, further destroying sludge floc cells. Then the bound water in the sludge flocs was released, thereby improving the sludge dewaterability. The microscopic morphology also indicated that the sludge flocs have a blocky structure with tight texture before conditioning. After conditioning, the sludge flocs become smaller, and many irregular pores are formed on the surface, which facilitates the passage of internal moisture. Economic analysis showed that Fe2++PMS conditioning is more economical than the traditional Fenton method. [ABSTRACT FROM AUTHOR]

Dissolved organic matter (DOM) elucidated from biochars enhances the dissolution of iron oxides and reduction of iron. However, given that reduction mechanism of iron (Fe(III)) in the practical biochar applications for soil amendment and environmental remediation have not been fully elucidated, this study laid great emphasis on the photo-induced Fe(II) liberated from DOM-Fe(III) complexes. Thus, pyrolysis of biomass was carried out at 300 °C to maximize DOM release from biochars. Moreover, three different biomass samples (rice straw (R), granular sludge (G) from an anaerobic digester, and spent coffee grounds (C)) were chosen as carbon substrates for biochars preparation. To demonstrate the transformation of Fe(III), 1 and 5 wt% biochar was applied to the clean (S1) and arsenic-contaminated (S2) soil with/without the light. The results indicate that the light condition produces more Fe(II). The amount of Fe(II) accounts for 25.3, 28.6, and 30.7% of total iron under the light with 5 wt% GB, RB, and CB in S1, and 10.6, 13.1, and 13.8% in S2. This study demonstrates that Fe(II) is generated more under ultraviolet irradiation than visible light and dark condition. In addition, a control experiment without biochar showed that DOM plays an important role in the reduction of Fe(III). The mobility of arsenic increased under the light condition since the intermediates of DOM photo-degradation accelerates the dissolution of iron oxides and arsenic competes with DOM for the adsorption. Therefore, there was no significant correlation between the elution of arsenic and the formation of Fe(II) during the reductive dissolution of iron oxide under the light condition. Unlabelled Image • Employing biochar increases the complexation of DOM-Fe(III) in the aqueous phase. • The complex of DOM-Fe(III) under the light produces more Fe(II). • There was no significant correlation between the photo-reduction of Fe(III) and mobility of As. [ABSTRACT FROM AUTHOR]

Membrane fouling is an obstacle impeding the wide applications of ceramic membranes and organics are responsible for most of the membrane fouling issues in wastewater treatment. In this study, Fenton cleaning strategy was firstly proposed to clean ceramic membrane fouling in wastewater treatment. Fe2+ efficiently catalyzed fouling cleaning with H 2 O 2 (1.5%) to recover the filterability of ceramic membrane. The maximum ∆ TMP recovery (over 99%) was achieved at an optimal Fe2+ dosage of 124 mg/L after 6 hr of immersion cleaning. The total residual membrane fouling resistance decreased gradually from this optimum value as the Fe2+ dosage increased above 124 mg/L. The residual hydraulically reversible fouling resistance accounted for most of the membrane fouling and was basically removed (≤ 3.0 × 109 m−1) when Fe2+ dosages higher than 124 mg/L were used. The foulants responsible for the formation of a residual hydraulically reversible fouling layer (DOC (dissolved organic carbon), proteins, polysaccharides, EEM (fluorescence excitation-emission matrix spectra), SS (suspended solids), and VSS (volatile suspended solids)) were gradually removed as the Fe2+ dosage increased. These residual organic foulants were degraded from biopolymers (10–200 kDa) to low molecular weight substances (0.1–1 kDa), and the particle size of these residual foulants decreased significantly as a result. The strong oxidation power of hydrogen peroxide/hydroxy radicals towards organic foulants was enhanced by Fe2+. Fe2+ played a significant role in the removal of hydraulically reversible fouling and irreversible fouling from the ceramic membrane. However, Fe2+ (≥ 124 mg/L) increased the likelihood of forming secondary iron-organics aggregates. Unlabelled Image [ABSTRACT FROM AUTHOR]

Hinokitiol, a natural lipophilic chelator, appears capable of replacing several iron transporters after they have been genetically ablated. Divalent metal-ion transporter (DMT1) is the major iron importer in enterocytes and erythroblasts. We have compared DMT1 and hinokitiol in multiple fashions to learn if the smaller molecule is a suitable substitute using two HEK293 cell lines engineered to overexpress different isoforms of DMT1. Both the macromolecule and the lipophilic chelator enable import of ferrous ions into HEK293 cells. Hinokitiol also mediates ferric ion import but DMT1 cannot do so. While DMT1 can also import Mn2+ ions, hinokitiol lacks this ability. The Michaelis–Menten analysis for kinetics of macromolecular catalysis is also suitable for hinokitiol-supported iron import. To compare hinokitiol to DMT1 relative to other metal ions that DMT1 can transport, we employed an organic extraction procedure with which we initially matched the results obtained for Fe2+, Fe3+ and Mn2+, and then showed that multiple other cations were unlikely to enter via hinokitiol. The small chelator thus shares some functional properties with DMT1, but distinct difference were also noted. [ABSTRACT FROM AUTHOR]

Restoration of submerged macrophytes is an efficient way for endogenous nutrient control and aquatic ecological restoration, but slow growth and limited reproduction of submerged macrophytes still exist. In this research, the effect of ferrous on the seed germination and growth of Vallisneria natans (V. natans) were studied through aquatic simulation experiments and its influence on the rhizosphere microbial community was also explored. The seed germination, growth, and physiological and ecological parameters of V. natans were significantly affected by the ferrous treatments. Ferrous concentration above 5.0 mg/L showed significant inhibition of seed germination of V. natans and the best concentration for germination was 0.5 mg/L. During the growth of V. natans, after ferrous was added, a brief period of stress occurred, which then promoted the growth lasting for about 19 days under one addition. The diversity and richness of the rhizospheric microbial were increased after the ferrous addition. However, the function of the rhizospheric microbial community showed no significant difference between different concentrations of ferrous adding in the overlying water. Ferrous addition affected the growth condition of plants (content of CAT, Chl a , Chl b , etc.), thus indirectly affecting the rhizospheric microbial community of V. natans. These impacts on V. natans and rhizosphere microorganisms could generalize to other submerged macrophytes in freshwater ecosystems, particularly which have similar habits. These findings would contribute to the ecological evaluation of ferrous addition or iron-containing water, and provide a reference for submerged macrophytes restoration and ecological restoration in freshwater ecosystems. [Display omitted] • 0.5 mg/L ferrous addition significantly improved the germination of V. natans seeds. • Ferrous addition contributed to promoting growth and leaf chlorophyll content. • The diversity and richness of rhizosphere microbes of V. natans were increased. • Addition ferrous can be utilized in promoting submerged macrophytes restoration. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Fe2+/OA/PS system was efficient over a wide pH range. • Exogenous Fe2+ and Fe3+ dissolved from soil participated in PS activation. • CO 2 •- radicals contributed to the reduction of Fe3+/Fe3+-OA. • TCS degradation pathways were proposed in the Fe2+/OA/PS system. • Column experiments simulated TCS in-suit remediation in the Fe2+/OA/PS system. Triclosan (TCS) is a compound in pharmaceutical and personal care products (PPCPs) that preferentially accumulates in soil and may threaten human health. Iron-based persulfate activation processes (Fe-PAPs) are a promising technique in soil remediation but are limited by their narrow pH application range and resultant iron precipitation. In this study, oxalic acid (OA) was specifically introduced to improve the efficiency of Fe2+-activated persulfate (PS) processes for TCS degradation in soil. The complexation of OA and Fe2+ improved the total iron concentration in the Fe2+/OA/PS system and prevented iron precipitation. Fe-minerals in soil were also dissolved by OA, which participated in PS activation. The most appropriate proportion of Fe2+/OA/PS is 1:1:1, and approximately 85% of the TCS was degraded within 240 min compared with 45% in the Fe2+/PS system. SO 4 •- and 1O 2 played important roles on TCS oxidation, while O 2 •- and CO 2 •- mainly participated in the iron cycle. The weak stretch of Fe-O in OA containing treatments in ATR-FTIR measurements provided evidence that OA dissolved the Fe-minerals. The introduction of OA in the Fe2+/PS system in four different soils reduced the negative effect of soil organic matter on TCS degradation. Three types of intermediates including hydroxylation, cleavage of ether bonds and cyclization products, were identified by LC-Q-TOF-MS. Column experiments were used to study the feasibility of in situ chemical oxidation (ISCO) remediation of TCS in the Fe2+/OA/PS system. Our findings indicated the ability of OA to be used as a cheating agent in Fe-PAPs for TCS soil remediation. [ABSTRACT FROM AUTHOR]

A study of the pretreatment stage and subsequent leaching of a mixed copper ore with different chloride solutions containing iron was carried out. The first stage considered pretreatment tests to decide the best conditions. Two levels of each factor were analyzed, 20 and 50 kg/t of NaCl, 17 and 25 kg/t of H2SO4, 0 and 25 kg/t of Fe2(SO4)3·9.2H2O, 0 and 25 kg/t of Fe2SO4·7H2O, and a curing time of 15 and 30 days. The results showed a significant effect of NaCl and curing time on the extraction, and less effect was found with the variation of acid and iron salts. The second stage included column leaching using a solution with 0.5 g/L of Cu+2, 80 g/L of Cl−, 10 g/L of H2SO4, and variable concentrations of ferric and ferrous ions (0 and 2 g/L). The best copper extraction of 80.2% was found considering a pretreatment of 30 days, 25 kg/t of H2SO4, 50 kg/t of NaCl, and a leaching solution concentration described previously with 2 g/L of Fe+2. The results showed the leaching of all copper oxide species and 20% of the copper sulfide species. In addition, there was a reduction in the acid consumption as the resting time increases. Furthermore, to evaluate a possible decrease in time and acid in pretreatment and chloride in leaching, tests including 10 and 25 kg/t of H2SO4 and 1, 15, and 30 days of curing and a diminution of the NaCl concentration to 20 g/L (content from seawater) were executed. The results showed a significant effect on curing time below 15 days. Furthermore, the slight influence of the decrease of acid on copper extraction gives cost reduction opportunities. The diminution of chloride concentration (80 to 20 g/L) in leaching solution decreases the extraction from 79% to 66.5%. Finally, the Mellado leaching kinetic model was successfully implemented.

In this work, the removal of arsenic from aqueous solution by using FeSO 4 with CaCO 3 was investigated. Arsenic removal was significantly improved in the presence of CaCO 3 , compared with Ca(OH) 2 , giving an arsenic removal rate of 99.64% with the Fe/As molar ratio of 2:1 and Ca/Fe molar ratio of 1.5:1. With both FeSO 4 +Ca(OH) 2 (FSCH) and FeSO 4 +CaCO 3 (FSCC), several analytical methods including SEM-EDS, XRD, FTIR, and TG-DSC etc. were performed to characterize the sediments. The sediment from FSCC has much larger particle size, six time faster filtration speed and only one-third volume compared with that from traditional FSCH, allowing a very easy handling of the precipitate sludge, another clear advantage of using CaCO 3. Moreover, much less fine and sticky CaSO 4 was generated in the FSCC sludge than that from FSCH. Image 10298911 • Arsenic removal dramatically improved by CaCO 3 instead of Ca(OH) 2 with FeSO 4. • The sludge after arsenic removal by CaCO 3 with FeSO 4 is easy handling. • Sludge from CaCO 3 has six time faster filtration speed than that from Ca(OH) 2. • Sludge from CaCO 3 only has one-third volume compared to that from Ca(OH) 2. [ABSTRACT FROM AUTHOR]

Activated carbon (AC) is widely used for removing organic contaminants; however, its finite adsorption capacity may limit the long-term use. Oxidation regeneration of saturated AC is one of the effective measures to recover the adsorptive capacity of AC, even though the deterioration of AC during the regeneration is common. In this study, advanced oxidation process (Fenton combined persulfate system, Fe2+/H2O2/S2O82-) was used to regenerate the saturated AC, the mechanisms of AC deterioration were evaluated, and the interactions of oxidants, contaminants, and AC during the adsorption/regeneration processes were investigated. The results indicate that the oxidants mainly functions on the AC surface, resulting in the deterioration of AC along with the destruction of the sorbed contaminant (e.g., trichloroethylene in this study). Deterioration of AC exposed fresh carbon to the surface, however, such emergence of the fresh carbon to the AC surface does not seem to increase the AC adsorption capacity. Iron precipitation on the surface of AC was also observed during the adsorption/regeneration process, however, it can be partially removed from the surface of AC along with the carbon deterioration. [ABSTRACT FROM AUTHOR]

Highlights • Iron pretreatment significantly mitigates ceramic membrane fouling. • Ferrate pretreatment achieves the best membrane fouling control performance. • Ferrate greatly improves the water quality of reclaimed water. • Biopolymers with the MW of 20–2000 kDa are mainly removed. • Ferrate has dual functions of chemical oxidation and coagulation. Abstract Coagulation-membrane filtration hybrid process has been widely applied in water treatment to improve water quality and alleviate membrane fouling. Herein, we systematically investigated the comparable effect of ferrate, ferrous and ferric pretreatment on fouling alleviation of ceramic membrane in reclaimed water treatment. Our results showed that the pretreatment of ferric, ferrous and ferrate remarkably alleviated membrane fouling with the fouling alleviation performance following the order: ferrate > ferrous > ferric > control. The t crit (subcritical fouling time) after which the fouling rate (dTMP/dt) became much more severe was remarkably extended from 0 (control) to 432 (ferric), 576 (ferrous) and 888 h (ferrate), respectively. Meanwhile, hydraulically reversible fouling resistance had the greatest contribution (58.3%) to the overall fouling resistance in the control case, however, hydraulically irreversible membrane fouling caused by inorganics (R ir-citrate) became more severe in long-term operation with the contribution of R ir-citrate to the total fouling resistance of 40.7%, 46.3% and 50.3% in the cases with ferric, ferrous and ferrate pretreatment, respectively. Moreover, the redundancy analysis results showed that the alleviated membrane fouling was principally owing to the sharp reduction of organic matters and the significant increase of particle size and particle concentration in influent. Compared with ferric and ferrous, ferrate had the best fouling alleviation performance, which was mainly due to its dual functions of chemical oxidation (including OH, Fe(V) and Fe(IV)) and coagulation (ferric oxyhydroxides). [ABSTRACT FROM AUTHOR]

Abstract Ferrous dosing is used to reduce phosphorus concentration and alleviate polymeric membrane fouling in membrane bioreactor (MBR). However, limited studies have been conducted to investigate the impacts of ferrous dosing on ceramic membrane fouling, nutrient removal efficiency and microbial community. Accordingly, the aim of this study was to investigate the effect of intermittent ferrous dosing with Fe/P molar ratios of 2 and 1 (with a dosing frequency of every two days) on the overall nutrient removal, functional microbial changes and membrane fouling in ceramic membrane bioreactors (CMBR) in treatment of wastewater. TP concentration of 10 mg/L in influent decreased to 1.94 ± 0.62 mg/L (control), 0.38 ± 0.22 mg/L (Fe/P = 1) and 0.31 ± 0.18 mg/L (Fe/P = 2) in the effluent, respectively. Meanwhile, the effluent total nitrogen (TN) concentrations with Fe/P = 1 treatment (6.80 ± 2.02 mg/L) and Fe/P = 2 treatment (5.12 ± 2.28 mg/L) were lower than that of the control (7.72 ± 2.36 mg/L). Compared to Fe/P = 1, the TN removal performance was better for Fe/P = 2 mainly due to the increased abundance of denitrifying bacteria (Zoogloea and Acinetobacter). In addition, excess iron dose might have toxic effects on bacterial physiology, however the Fe concentrations that cause cell damage vary for different bacteria. The relative abundance of Zoogloea (aerobic denitrifying bacteria) continuously increased with ferrous addition (Fe/P = 2), while other bacteria including Dechloromonas , Hyphomicrobium and Thauera (anoxic denitrifying bacteria), Nitrospira (nitrifying bacteria) and Candidatus Accumulibacter (phosphorus accumulating organism) decreased sharply. Furthermore, membrane fouling was effectively moderated by ferrous dosing and Fe/P = 1 treatment showed improved membrane fouling mitigation than Fe/P = 2. Overall, intermittent ferrous addition in CMBR with Fe/P molar ratio of 1 was beneficial to the removal of nutrients (TP, TN and organics), enhanced succession of microbial community and membrane fouling mitigation. Graphical abstract Unlabelled Image Highlights • Ferrous dosing (Fe/P = 1) is beneficial to phosphorus and nitrogen removal. • Microbial community of activated sludge is significantly changed by ferrous dosing. • Excess iron dose has toxic effects on bacterial physiology. • The optimal fouling control performance is achieved at Fe/P molar ratio of 1. [ABSTRACT FROM AUTHOR]

Abstract A simple and novel method was developed at first time to enhance As (V) removal by zero valent iron (ZVI) and activated ZVI/Fe 3 O 4 media (AIM) through air injection at intervals. Fe (II) was essential to trigger As (V) removal by ZVI and AIM, and magnetite did not improve As (V) removal. In presence of 0.5 mM Fe (II) under anaerobic condition, 10 g L−1 ZVI and AIM showed same As (V) removal efficiency including percentage, capacity and rate of >99.999%, 3.0 mg/g ZVI/AIM and 0.013 mg As (V)/(g · min), respectively. Compared to the passivation of ZVI and AIM after one-time air injection, As (V) removal efficiency was significantly improved by intermittent air injection with increased air volume and injection frequency. After third time of 1.0 mL air injection at 30 min intervals, As (V) removal percentage and capacity remained same remarkable values as that under anaerobic condition, but total removal rate was further improved to 0.033 mg As (V)/(g · min). XPS results indicated that As (V) was completely reduced to As (III) and As (0) by Fe (0) under anaerobic condition, but quick adsorption/co-precipitation of As (V) followed by reduction to As (III) and As (0) by Fe (0) was the main mechanism under aerobic condition. This study suggests the addition of Fe (II) followed by simple air injection at intervals harnesses the reactivity of traditional ZVI for arsenic removal. Graphical abstract Image 102718 Highlights • Fe (II) was essential to activate ZVI and AIM systems to remove As (V). • ZVI and AIM showed high As (V) removal percentage, capacity and rate anaerobically. • As (V) removal efficiency was significantly improved by injecting air at intervals. • As (V) removal mechanisms under aerobic and anaerobic conditions were described. [ABSTRACT FROM AUTHOR]

This paper reviews the current quality of groundwater in Vietnam. In Vietnam, groundwater is obtained primarily from tubewells, which have high concentrations of pollutants such as As, Fe, Mn, and NH4+. In the areas where groundwater tests were conducted, arsenic levels ranged from 0.1-3050 μg/L, which substantially exceed the standard of 10 μg/L which has been established by the WHO. Contamination sources are distributed over a large area from the Red River Delta in the north to the Mekong River Delta in the south, putting as many as ten million people at risk of adverse health effects. Levels of arsenic and iron in sediment are strongly correlated, which indicate that the presence of arsenic in groundwater results from the reduction of arsenic bound to iron oxyhydroxides. It is important to raise awareness of these issues among the Vietnamese public by disseminating information about the negative effects of contaminated drinking water, as well as carrying out long-term research projects to identify other sources of contamination and improving water treatment technology and water management capabilities. [ABSTRACT FROM AUTHOR]

Abstract Mineral scale deposition is a water-associated production threat for oil and gas productions. Scale deposition can lead to pipe throughput reduction and change in facility surface properties. Scale inhibitors are widely used in oilfield operations to control scale deposition. Fe(II) (ferrous) species is commonly encountered in oilfield produced waters and it is widely recognized that the presence of Fe(II) can impact the performance of scale inhibitors. However, the existing experimental results of Fe(II) impact on scale inhibitors are controversial, especially in barium sulfate system. This is partially due to the difference in dissolved oxygen level among different studies since a trace amount of dissolved oxygen can readily oxidize Fe(II) into Fe(III). In this study, a rigorously-maintained laser-based anoxic experimental setup was adopted to evaluate the impact of Fe(II) species on scale inhibitor performance in controlling barium sulfate scale. The anoxic setup utilized argon gas purging and reducing chemical addition and can maintain a dissolved oxygen level in μg L−1 (ppb) level. The experimental results suggest that at an anoxic condition, the presence of Fe(II) has a detrimental impact on the performance of scale inhibitors and such impact varies with different types of scale inhibitors. Solution pH and temperature can also affect the Fe(II) impact on scale inhibitors. In addition, two common oilfield chelating chemicals, i.e., EDTA and citrate, have been evaluated for their roles in reversing the detrimental impact of Fe(II) on scale inhibitors. It shows that at the experimental condition only citrate can effectively reverse the adverse impact of Fe(II) on scale inhibitor. This study provides the experimental approach and technical insights for evaluation of scale inhibitor performance in an anoxic condition. Graphical abstract Image 1 Highlights • A rigorous anoxic setup to study Fe(II) impact on scale inhibitor performance. • This setup can control dissolved oxygen in ppb level at elevated temperatures. • Fe(II) has a detrimental impact on phosphonate-based scale inhibitors. • Solution pH and temperature can affect Fe(II) impact on scale inhibitors. • Citrate can reverse the adverse impact of Fe(II) on scale inhibitors. [ABSTRACT FROM AUTHOR]