Initial Iron Concentration Research Articles

Significance of Initial Maternal Hemoglobin Concentration during Pregnancy in Birth Weight and Preterm Delivery in Sri Lanka

Objective: The study was conducted to investigate the influence of initial hemoglobin (Hb) concentration of Sri Lankan pregnant mothers on baby’s birth weight and preterm delivery. Methods: For this retrospective study, 3867 primigravid pregnant women in Sri Lanka were followed till they deliver the baby. Sampling method was cluster sampling where all the pregnant mothers giving singleton birth in the selected 15 health division were followed for three years. Mothers’ initial Hb concentration, weight gain during the pregnancy and neonatal outcomes were assessed. Results: Severe iron deficiency anemia at the initial stage of pregnancy had 3.9 - 14.4 folder higher relative risk of low birth weight (LBW) and 3.0 - 8.1 folder higher relative risk of preterm delivery at 95% confidence interval. The minimum incidence of preterm delivery and maximum weight gain of mothers occurs in association with an initial Hb concentration of 105 - 125 g/L. Conclusion: The excess level of initial iron content at pregnancy does not contribute for any adverse effect on pregnancy outcome as like in the later part of pregnancy and therefore supplement of iron during the initial pregnancy for mothers can be carried out regardless of whether the mother is anemic.

Sorption Recovery of Platinum (IV) from Hydrochloric Acidic Solutions in Presence of Iron (III), Copper (II) and Zinc

The present work is devoted to sorption preconcentration of platinum (II,IV) in the presence of iron (III), copper (II) and zinc from chloride solutions on the samples of CYBBER – new Russian brand of ion exchangers. The initial concentrations of platinum, iron and non-ferrous metal ions were 0.25, 0.5 and 2.0 mmol/L, respectively. The acidity of the investigated solutions was 0.01 – 2 mol/L. It was shown that the ion exchangers possess high sorption ability to the noble metal ions, and allow the quantitative recovery of these ions. It was also found out that platinum can be isolated from the accompanying components by means of separate elution with 0.001 M HCl (iron ions), 0.5 M HNO 3 (non-ferrous metal ions) and thiourea solution (80 g/L) in 0.3 M H 2 SO 4 (platinum ions).

Role of Iron Concentration on Hydrogen Production Using Confectionery Wastewater

AbstractHydrogen has been recognized globally as an energy carrier that fulfills all the environmental quality, energy security and economic competitive demands. In the present study, batch experiments were performed using confectionery wastewater to examine the influence of initial substrate and iron concentrations on hydrogen production. For the different initial substrate concentrations of 1,000, 3,000, 5,000, 7,000, and 9,000 mg COD/L, the obtained cumulative hydrogen production were 600, 1,325, 1,565, 1,825, and 915 mL, respectively. It was observed that the maximum cumulative hydrogen production of 1,825 mL was obtained at 7,000 mg COD/L. On this basis, further experiments were intended to study the role of iron concentration on hydrogen production by varying the iron concentration from 0.0, 0.05, 0.10, 0.15, 0.20 to 0.25 g/L at constant 7,000 mg COD/L of initial substrate concentration and initial pH of 5.5. It was inferred that the maximum cumulative hydrogen production of 2,475 mL was obtaine...

Bioleaching of different copper sulphide minerals and their physicochemical properties dependence

This paper investigated the bioleaching of different copper sulphide minerals. The bioleaching experiments show that the order of the copper bioleaching rates of four copper sulphide minerals, regardess of whether the optimum conditions or the initial ferrous iron concentration of 0 g L− 1, was identical: djurleite> bornite> covellite> chalcopyrite. Properties of mineral, such as rest potential, lattice energy, conductivity type and solubility product constant, are the intrinsic factors influencing the bioleaching of minerals. Among these parameters, rest potential and lattice energy can explain the difference of the bioleaching of four copper sulphide minerals. Conductivity type can interpret the low copper leaching efficiency of chalcopyrite and covellite. However, it cannot explicate the high copper leach rate of djurleite and bornite. The decrease of the lag phase of Acidithiobacillus ferrooxidans with an increase of solubility product constant of minerals is observed in the bioleaching system of four copper sulphide minerals. However, solubility product constant is not the crucial parameters dominating the bioleaching efficiency of copper sulfide minerals.

Optimal conditions for biological hydrogen production from food waste

Biohydrogen production from food waste via dark fermentation was conducted by using mixed culture under various environmental conditions (initial pH, initial F/M ratio, initial ferrous iron (Fe 2+ ), and temperature condition) in batch reactor. The results revealed that the maximum hydrogen yield of 46.19 mL H₂/g CODadd was achieved at the optimal conditions (initial pH 8.0, initial F/M ratio 4.0, initial iron concentration 100 mg FeSO₄/L and thermophilic condition (55±1°C)). Furthermore, major volatile fatty acid (VFA) productions of butyrate (765.66 mg/L) and acetate (324.69 mg/L) were detected and COD removal efficiency was detected at 66.00%. Therefore, these optimal conditions could be recommended to operate a system.

Features of Bivalent and Trivalent Iron Oxide Reduction from Slag with Carbon

Liquid-phase reduction of bi- (FeO) and trivalent (Fe 2 O 3 ) iron from slag with activated coal is studied: BAU (wood) and KAD (bituminous). Kinetic relationships are obtained for reduction at 1450°C from slag with an initial overall iron content Fe tot ≈ 5%. It is shown that regardless of the type of coal liquid-phase reduction of iron to metal from slag with a preponderance of Fe 2 O 3 is difficult compared with slag containing mainly FeO and requires preliminary reduction of trivalent to bivalent iron. A relationship is established for the rate of liquid-phase reduction on carbon reducing agent properties (structure porosity, ash content, sulfur content). The greater reducing capacity of BAU coal compared with KAD correlates with the lower ash and sulfur content of BAU coal.

Microcontaminant degradation in municipal wastewater treatment plant secondary effluent by EDDS assisted photo-Fenton at near-neutral pH: An experimental design approach

This work aims to evaluate the applicability of EDDS (ethylenediamine-N,N′-disuccinic acid) as an iron chelating agent for photo-Fenton treatment of municipal wastewater spiked with organic contaminants at near-neutral pH. A series of laboratory scale experiments are conducted under simulated sunlight in accordance with a central composite experimental design in order to define the most favorable conditions in terms of initial iron concentration (maintaining a molar ratio 1:2 of Fe:EDDS), H2O2 and pH. The system is evaluated in terms of degradation efficiency, H2O2 consumption and iron availability. The simulated system has been compared in terms of degradation efficiency with a 60L compound parabolic collector (CPC), and significant correlation has been observed. An approach for estimating near-optimal regions of operability is also demonstrated.

Synthesis of Some Chitosan Derivatives and Their Iron (II) Adsorption Behavior- a Class of Pharmaceutically Important Biosorbents

In the present study, chitin was isolated from the shells of freshwater crab (Sartoriana spinigera), available in Bangladesh. The isolated chitin was converted into chtiosan by deacetylation reaction. The chtiosan was characterized by FT-IR and 1H-NMR spectral analyses. The prepared chitosan was reacted with glutaradehyde, vanillin and salicylaldehyde to synthesize chitosan Schiff bases- vanillin-chitosan, salicylaldehyde-chitosan and glutaradehyde-chitosan. Iron (II) adsorption behavior of these derivatives was studied under varying experimental conditions such as contact time and initial concentration of iron (II) solution. The equilibrium adsorption data were fitted to Freundlich and Langmuir adsorption isotherm models and the model parameters were evaluated. Both the models represented the experimental data satisfactorily. Maximum adsorption capacity for iron (II) ions on chitosan, vanillin-chitosan, salicylaldehyde-chitosan and glutaradehyde-chitosan was evaluated and found be to 68.03, 35.59, 7.50 and 4.78 mg/g, respectively. The uses of chitosan derivatives as environment friendly biosorbents in pharmaceutical and API industries have been hightlighted. DOI: http://dx.doi.org/10.3329/bpj.v17i2.22340 Bangladesh Pharmaceutical Journal 17(2): 193-201, 2014

Redox Properties and Activity of Iron–Citrate Complexes: Evidence for Redox Cycling

Iron in iron overload disease is present as non-transferrin-bound iron, consisting of iron, citrate, and albumin. We investigated the redox properties of iron citrate by electrochemistry, by the kinetics of its reaction with ascorbate, by ESR, and by analyzing the products of reactions of ascorbate with iron citrate complexes in the presence of H2O2 with 4-hydroxybenzoic acid as a reporter molecule for hydroxylation. We report -0.03 V < E°' > +0.01 V for the (Fe(3+)-cit/Fe(2+)-cit) couple. The first step in the reaction of iron citrate with ascorbate is the rapid formation of mixed complexes of iron with citrate and ascorbate, followed by slow reduction to Fe(2+)-citrate with k = ca. 3 M(-1) s(-1). The ascorbyl radical is formed by iron citrate oxidation of Hasc(-) with k = ca. 0.02 M(-1) s(-1); the majority of the ascorbyl radical formed is sequestered by complexation with iron and remains EPR silent. The hydroxylation of 4-hydroxybenzoic acid driven by the Fenton reduction of iron citrate by ascorbate in the presence of H2O2 proceeds in three phases: the first phase, which is independent of the presence of O2, is revealed as a nonzero intercept that reflects the rapid reaction of accumulated Fe(2+) with H2O2; the intermediate oxygen-dependent phase fits a first-order accumulation of product with k = 5 M(-1) s(-1) under aerobic and k = 13 M(-1) s(-1) under anaerobic conditions; the slope of the final linear phase is ca. k = 5 × 10(-2) M(-1) s(-1) under both aerobic and anaerobic conditions. Product yields under aerobic conditions are greater than predicted from the initial concentration of iron, but they are less than predicted for continuous redox cycling in the presence of excess ascorbate. The ongoing formation of hydroxylated product supports slow redox cycling by iron citrate. Thus, when H2O2 is available, iron-citrate complexes may contribute to pathophysiological manifestations of iron overload diseases.

Copper leaching from waste electric cables by biohydrometallurgy

This study examines the leaching of copper from waste electric cables by chemical leaching and leaching catalysed by Acidithiobacillus ferrooxidans in terms of leaching kinetics and reagents consumption. Operational parameters such as the nature of the oxidant (Fe3+, O2), the initial ferric iron concentration (0–10g/L) and the temperature (21–50°C) were identified to have an important influence on the degree of copper solubilisation. At optimal process conditions, copper extraction above 90% was achieved in both leaching systems, with a leaching duration of 1day. The bacterial leaching system slightly outperformed the chemical one but the positive effect of regeneration of Fe3+ was limited. It appears that the Fe2+ bio-oxidation is not sufficiently optimised. Best results in terms of copper solubilisation kinetics were obtained for the abiotic test at 50°C and for the biotic test at 35°C. Moreover, the study showed that in same operating conditions, a lower acid consumption was recorded for the biotic test than for the abiotic test.

Study on degradation of nitrobenzene in groundwater using emulsified nano-zero-valent iron

Emulsified nano-zero-valent iron (EZVI) is a modified form of bare nanoiron with improved transportability and targetability for the remediation of organic-solvents polluted soil and groundwater. In this work, EZVI (50–150 nm) was prepared by coating an emulsified vegetable oil membrane on the surface of Fe nanoparticles. EZVI was well-dispersed and less aggregation was observed. Batch experiments were conducted in anaerobic conditions to investigate the kinetics of nitrobenzene reduction by EZVI and the influences of oil concentration, initial iron content, and initial pH. Results indicated that the kinetics of nitrobenzene reduction by EZVI followed a pseudo-first-order kinetics. The observed rate constant of nitrobenzene is 0.0942 min−1. The oil concentration of 1 and 2 % tended to be preferred concentrations. The rate of nitrobenzene degradation and aniline formation increased with increasing iron content. The low pH is favorable to the nitrobenzene reduction by EZVI.

Iron Minerals Removal from Different Quartz Sands

Quartz sand occurs in varying degrees of purity in dependence on the iron mineral composition, but only a small percentage is suitable for the glass industry after washing and magnetic separation treatment. Bioleaching in combination with washing can increase the quality of quartz sands. The addition of glucose in the leaching medium was important for the continuing leaching activity of iron by heterotrophic bacteria. The amount of bacterial iron removal was not directly proportional to the initial iron content of untreated samples. It was dependent on the mineralogical composition of the quartz sandswith kaolinite, illite encapsulated and sealed by goethite (Q1), quartz sands with phengite, kaolinite encapsulated and sealed by siderite (Q2), quartz sands with glauconite encapsulated and sealed by clinoptilolite and Fe smectite (Q3). Heterotrophic bacteria decomposed these sealed polymineral grains with the iron dissolution and caused the formation of a fine–grained fraction of mineral particles predominantly below 49μm in size. Bioleaching resulted in a 50% decrease in Fe content of Q1, in a 47% decrease in Fe content of Q2 and in a 30% decrease in Fe content of Q3 after 83 days bacterial treatment. This bioleaching pretreatment may be used for the decomposition of iron minerals sealed by silicate minerals and the removal iron surface coatings from different quartz sands. The elutriation process can removed the fine–grained iron particles bioformed after bioleaching. The reductive dissolution of iron polyminerals and washing process may have biotechnological application in the quality improvement of quartz sands.

Thermodynamic and kinetic studies of biosorption of iron and manganese from aqueous medium using rice husk ash

The adsorption behavior of rice husk ash with respect to manganese and iron has been studied by batch methods to consider its application for water and waste water treatment. The optimum conditions of adsorption were determined by investigating the effect of initial metal ion concentration, contact time, adsorbent dose, pH value of aqueous solution and temperature. Adsorption equilibrium time was observed at 120 min. The adsorption efficiencies were found to be pH dependent. The equilibrium adsorption experimental data were found to fit the Langmuir, Freundlich and Temkin isotherms for iron, but fitted only Langmuir isotherm for manganese. The pseudo-second order kinetic model was found to describe the manganese and iron kinetics more effectively. The thermodynamic experiment revealed that the adsorption processes involving both metals were exothermic. The adsorbent was finally applied to typical raw water with initial manganese and iron concentrations of 3.38 mg/l for Fe and 6.28 mg/l, respectively, and the removal efficiency was 100 % for Mn and 70 % for Fe. The metal ions were desorbed from the adsorbent using 0.01 M HCl, it was found to quantitatively remove 67 and 86 % of Mn and Fe, respectively, within 2 h. The results revealed that manganese and iron are considerably adsorbed on the adsorbent and could be an economic method for the removal of these metals from aqueous solutions.

Coating Effects of Nano-Sized Particles onto Sand Surfaces: Small Strain Stiffness and Contact Mode of Iron Oxide–Coated Sands

AbstractThe presence of nano-sized particles on the surface of sand grains can significantly influence the mechanical, physical, and chemical behavior of the sand because of the effects of contacts between particles. This study quantified the change in small strain stiffness caused by the presence of iron oxide particles (hematite and goethite) that were chemically sorbed onto uncemented silica sand. Particularly, the change in contact mode between sand particles, caused by the presence of the nanoparticles, was studied. The iron oxide coating density of coated sands was controlled by changing the substrate sand particle size, ranging from 0.11 to 0.72 mm in diameter, with corresponding iron contents ranging from 0.13 mg iron oxide/g sand (goethite) to 6.4 mg iron oxide/g sand (hematite). The presence of the iron oxide nanoparticles altered the contact mode between particles and, correspondingly, the small strain stiffness as a function of the initial relative density, applied stress, iron content, and su...

Kinetic Modeling of Chemical Degradation Phenomena in Fuel Cell Ionomers

A kinetic model has been developed to describe the chemical degradation of Nafion-type polymer electrolyte membranes. The model accounts for pathways of radical formation and consumption along with mechanisms of ionomer degradation through radical attack. Systematic simplifications on the set of model equations lead to analytical expressions for concentration of aggressive hydroxyl radical as a function of initial iron content and hydrogen peroxide concentration. The ionomer degradation model employs a coarse-grained structure of Nafion ionomer. . It distinguishes units corresponding to head groups and trunk segments of sidechains. The backbone segment between two sidechains is the third unit considered in the degradation model. A set of differential equations is formulated to describe the consumption of these units and determine the associated rate of fluorine loss and the change in the ion exchange capacity (IEC). A parametric study was performed to study the impact of different degradation mechanisms, degradation conditions, and chemistries of the PFSA on fluorine loss and IEC change. The rate constants of degradation processes are found through comparison with the experimental degradation data. Results will be discussed in view a structural stabilization of PEMs and the mitigation of chemical degradation.

Iron-related carrier traps near the n+p-junctions of crystalline silicon solar cells: impacts of feedstock and of the fabrication processes

An influence of the iron content in the crystal on the formation of carrier traps in the silicon solar cells was studied. Mesa-structured n+p-junctions were formed on the surface of Cz-Si wafers after various stages of a standard solar cell fabrication process. Majority carrier traps in/near the junction volume were investigated by deep level transient spectroscopy (DLTS). The trap density correlated with the total iron content in the wafers and dropped strongly with the distance from the junctions. Our results suggest that the traps were formed during the phosphorus diffusion process and/or during the subsequent cooling. The initial iron content in the wafers influenced changes in the trap concentrations at further fabrication steps. The present study could help in increasing solar cell efficiencies by tailoring the fabrication processes according to the contamination in the feedstock.

Removal of pharmaceuticals from MWTP effluent by nanofiltration and solar photo-Fenton using two different iron complexes at neutral pH

In recent years, membrane technologies (nanofiltration (NF)/reverse osmosis (RO)) have received much attention for micropollutant separation from Municipal Wastewater Treatment Plant (MWTP) effluents. Practically all micropollutants are retained in the concentrate stream, which must be treated. Advanced Oxidation Processes (AOPs) have been demonstrated to be a good option for the removal of microcontaminants from water systems. However, these processes are expensive, and therefore, are usually combined with other techniques (such as membrane systems) in an attempt at cost reduction. One of the main costs in solar photo-Fenton comes from reagent consumption, mainly hydrogen peroxide and chemicals for pH adjustment. Thus, in this study, solar photo-Fenton was used to treat a real MWTP effluent with low initial iron (less than 0.2 mM) and hydrogen peroxide (less than 2 mM) concentrations. In order to work at neutral pH, iron complexing agents (EDDS and citrate) were used in the two cases studied: direct treatment of the MWTP effluent and treatment of the concentrate stream generated by NF. The degradation of five pharmaceuticals (carbamazepine, flumequine, ibuprofen, ofloxacin and sulfamethoxazole) spiked in the effluent at low initial concentrations (μg L−1) was monitored as the main variable in the pilot-plant-scale photo-Fenton experiments. In both effluents, pharmaceuticals were efficiently removed (>90%), requiring low accumulated solar energy (2 kJUV L−1, key parameter in scaling up the CPC photoreactor) and low iron and hydrogen peroxide concentrations (reagent costs, 0.1 and 1.5 mM, respectively). NF provided a clean effluent, and the concentrate was positively treated by solar photo-Fenton with no significant differences between the direct MWTP effluent and NF concentrate treatments.

Enhancement of Scenedesmus sp. LX1 Biomass Production and Lipid Accumulation Using Iron in Artificial Wastewater and Domestic Secondary Effluent

While coupling wastewater treatment with microalgal bioenergy production is very promising, new approaches are needed to enhance microalgal growth and lipid accumulation in wastewater. Therefore, this study investigated the effect of iron on the growth, nutrient removal, and lipid accumulation of Scenedesmus sp. LX1 in both artificial wastewater and domestic secondary effluents. When increasing the iron concentration from 0 to 2 mg/l in the artificial wastewater, the biomass production of Scenedesmus sp. LX1 increased from 0.17 to 0.54 g/l; the nitrogen and phosphorus removal efficiency increased from 15.7% and 80.6% to 97.0% and 99.2%, respectively; and the lipid content was enhanced 84.2%. The relationship between the carrying capacity/maximal population growth rate of Scenedesmus sp. LX1 and the initial iron concentration were also in accordance with the Monod model. Furthermore, when increasing the iron concentration to 2 mg/l in four different domestic secondary effluent samples, the lipid content and lipid production of Scenedesmus sp. LX1 was improved by 17.4-33.7% and 21.5-41.8%, respectively.

Nitrate reduction by mixed iron(II-III) hydroxycarbonate green rust in the presence of phosphate anions: The key parameters influencing the ammonium selectivity

The reduction of nitrate anions by a mixed FeII–FeIII carbonated green rust (GR) in aqueous medium is studied as a function of the initial pH and the initial concentrations of iron, phosphate and nitrate. The influence of these parameters on the fraction of nitrate removed and the production of ammonium is investigated by the help of statistical experimental designs. The goal is to determine experimental conditions that maximize the fraction of NO3− removed and concomitantly minimize the production of NH4+. Increasing the phosphate concentration relatively to the initial FeII concentration inhibits the reduction of nitrate probably due to a surface saturation of the lateral sites of the GR crystals. The kinetics of the reaction is greatly enhanced by increasing the initial pH at 10.5, however it leads to a global increase of the NH4+ production. A partial saturation of the surface sites by phosphate leads to a global decrease of selectivity of the reaction towards ammonium. The evolution of the ratio of the NH4+ concentration to the FeII concentration confirms that the NO3− species are only partially transformed into ammonium. Interestingly at an initial pH of 7.5, the selectivity of the reaction towards NH4+ is often lower than ∼30%. The reduction of nitrate by carbonated GR differs from the behavior of other GRs incorporating Cl−, F− and SO42− anions that fully transform nitrate into ammonium. Finally, if GR is intended to be used during a passive water denitrification process, complementary dephosphatation and ammonium treatments should be considered.

Formation of jarosite and its effect on important ions for Acidithiobacillus ferrooxidans bacteria

The precipitation of jarosite adversely affects the bio-leaching of copper sulfides in the Sarcheshmeh heap bio-leaching process. The variables of the initial concentration of ferrous iron in the growth medium, pH, and temperature were examined in the laboratory to determine how they affect the precipitation of jarosite in the presence of Acidithiobacillus ferrooxidans bacteria. It was found that the maximum ferric precipitate occurred at a ferrous sulfate concentration of 50 g/L, a temperature of 32 °C, and an initial pH value of 2.2. The effects of the precipitation of ferric iron on the quantities of ions that are important for A. ferrooxidans bacteria in aqueous phase, i.e., ferric, sulfate, potassium, phosphate, and magnesium ions, also were assessed. The results showed relatively similar patterns for the ferric and potassium ions, and then reason might have been the co-precipitation of these ions as constituent elements of jarosite mineral. At pH values greater than 1.6, the solubility of phosphate ions decreased dramatically due to the co-precipitation of phosphate ions with the jarosite precipitate and due to the significant growth rate of A. ferrooxidans bacteria in this pH range. Due to the dissolution of a gangue constituent in the ore, the magnesium levels increased in the first few days of the bio-leaching process; thereafter, it decreased slightly.