Iron In Tap Water Research Articles

Iron Determination in Natural Waters Using a Synthesised 3-Hydroxy-4-Pyridione Ligand in a Newly Developed Microfluidic Paper-Based Device

This work describes the development of an iron sensor based on a microfluidic paper-based technique, to attain iron quantification in natural waters. A new water-soluble naphthalene-3-hydroxy-4-pyridione ligand was used as a colour reagent, as it formed an orange complex with iron. As a newly described ligand, several chemical and physical parameters, namely, the sample and reagent volumes and reagent concentrations, were studied related to the formation of the coloured complex. The microfluidic paper-based analytical device (μPAD) assembly, namely, the use of different types of filter paper and different numbers of layers, was developed to obtain the best performance. Under the optimal conditions, a linear correlation was obtained in the range of 0.25–2.00 mg/L of iron, with a minimum detectable value of 0.07 mg/L. The proposed μPAD method was validated by an analysis of the certified samples and by a comparison of the tested water samples with the inductively coupled plasma (ICP) results (RE < 10%). Then, the μPAD device was successfully applied to the determination of iron in tap water, well water, river water, and seawater, with no need for any prior sample pre-treatment; recovery studies were also performed (average = 100.3% with RSD = 4.2%).

Provision of Safe Drinking Water to the Local Population within the Clean Water Project Implemented in the Penza Region

Introduction: Drinking water from centralized drinking water supply systems is not always safe due to its natural pollution with various chemicals and microbiological contamination occurring in the distribution system. In this regard, the role of the service exercising governmental water quality surveillance is growing. The purpose of the study was to assess the quality of drinking water and the associated health risk and to substantiate priority measures aimed at improving the quality of water in the centralized water supply systems of the region. Materials and methods: We examined the results of drinking water quality testing performed within the implementation of sanitary and epidemiological surveillance and socio-hygienic monitoring and incidence rates in morbidity of population in 27 districts of the Penza Region and the regional center for the years 2014–2019. Health risks from oral exposures to waterborne chemicals were assessed in accordance with Guidelines R 2.1.10.1920–04. The statistical relationship was studied by the correlation method. Results: We established that water quality in the centralized water supply systems fed by underground sources is determined by the chemical composition of the exploited aquifers that divide the territory of the Penza Region into four zones. The worst water quality was observed in the fourth zone where concentrations of natural iron, fluorides and boron in tap water were many times higher than their maximum permissible levels and the hazard quotient for fluorides exceeded the limit value (HQ = 2.845 for children and 1.219 for adults). In the third zone, iron posed the highest risks of diseases of mucosa and skin (HI = 0.296), the immune system (HI = 0.311), and hematopoietic system (H = 0.473) in children; we also established a strong correlation between the average annual concentration of iron in tap water and the incidence of genitourinary disorders, gastritis and duodenitis in the child population. Although the share of the population supplied with safe drinking water from centralized water supply systems increased from 86.5 % in 2014 to 89.4 % in 2019, the target set within the Regional Clean Water Project for 2019 was not achieved. Conclusion: The study results were taken into account when making additions to the Regional Clean Water Project in 2020 envisaging construction of iron removal plants and water well drilling in areas with low fluorine levels.

Adsorption of Fe(II) and Fe(III) from aqueous solution by using sepiolite: speciation studies with MINEQL+ computer program

ABSTRACTAs a low-cost adsorbent, sepiolite has been used for the adsorption of Fe(II) and Fe(III) from aqueous solutions. The proposed method was applied to the determination of iron in tap water, employing standard addition. The results reported with a confidence interval for the 95% confidence level show the applicability of the proposed method to water analysis. Speciation studies are very important for understanding of the toxicity, bio-availability, bio-accumulation, and transport of an element in different environmental media. In this study, Fe(II) and Fe(III) speciation was investigated for optimum concentration and pH in aqueous solutions with MINEQL+ computer program.

Sensitive Determination of Iron Using Disposable Nafion-Coated Screen-Printed Graphite Electrodes

ABSTRACTIron was determined in drinking water using low-cost, disposable, and highly reproducible modified graphite screen-printed electrodes. Nafion is a chemically inert polymer and endows remarkable sensitivity for Fe(III) through interaction with the sulfonic groups on the polymer surface. The concentration of Nafion on the modified electrodes was optimized and the best results were obtained using 2 μL of 0.2% Nafion in ethanol. The preconcentration of analytes was performed in an electrodeless mode with stirring in 0.01 mol L−l HCl. Under selected conditions and for a preconcentration time of 60 s, square-wave voltammograms exhibited a cathodic peak, the height of which was linearly dependent on the concentration of iron from 0.05 to 5.00 µmol L−l. The limit of detection was 15 nmol L−l Fe(III). The developed electrodes were successfully used to determine iron in tap water. Accuracy of the method was evaluated with recovery measurements in spiked samples. The values were 108 ± 3%. Possible interferences from the coexisting ions were also investigated. The results show that the sensors are sensitive, selective, rapid, reliable, and suitable for the determination of Fe(III) in water.

Synthesis and physical characterization of Ag nanoparticles and their interaction with Fe

Silver nanoparticles (AgNPs) present unique physical and chemical properties such as chemical stability, huge superficial area and excellent optical properties, thus justifying the impact and variety of their applications: in material science, in electrochemistry, in electronic devices, as biological or chemical sensors, and in catalysis. Given the fact that there is a limited number of studies on synthesis of AgNPs compared with other nanomaterials, this article proposes a simple methodology for synthesizing AgNPs involving the wet chemical reduction of silver nitrate with gallic acid as a reduction/capping reagent. The reaction is carried out in absence or in presence of hydrogen peroxide; and the formation of AgNPs is monitored by UV–vis and fluorescence spectroscopy. Transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) were used for further characterization. Two main types of nanoparticles/nanodiscs were clearly identified in absence and in presence of hydrogen peroxide, respectively. Thus, AFM revealed the formation of AgNPs of 18.15 ± 1.95nm in diameter and of 2.21 ± 0.35nm high or of 9.16 ± 1.28nm in diameter and of 1.57 ± 0.17nm high. The STM technique revealed that average particle size was 4.59 ± 0.61nm with hydrogen peroxide and 3.84 ± 0.66nm without it. Therefore, the nanoparticle size obtained by AFM was strongly influenced by the capping thickness. The reduction in nanoparticle size was accompanied by increased uniformity and reproducibility. The fluorescence of the AgNPs was used to determine traces of iron in tap water and bottled water via an induced fluorescence quenching mechanism, thus aiding in establishing an analytical method.

Synergistic Effect of Molybdate and Monoethanolamine on Corrosion Inhibition of Ductile Cast Iron in Tap Water

Synergistic Effect of Molybdate and Monoethanolamine on Corrosion Inhibition of Ductile Cast Iron in Tap Water

New Mechanism on Synergistic Effect of Nitrite and Triethanolamine Addition on the Corrosion of Ductile Cast Iron

In general, we compared the different inhibition mechanisms of organic inhibitor with that of anodic inhibitor. When triethanolamine or nitrite was added separately to tap water for inhibiting the corrosion of ductile cast iron, large amounts of inhibitor were needed. This is because the corrosion inhibitors had to overcome the galvanic corrosion that occurs between graphite and matrix. In this work, we investigated the corrosion of ductile cast iron in tap water with/without inhibitors. The corrosion rate was measured using chemical immersion test and electrochemical methods, including anodic polarization test. The inhibited surface was analyzed using EPMA and XPS. Test solutions were analyzed by performing FT-IR measurement. When triethanolamine and nitrite coexisted in tap water, synergistic effect built up, and the inhibition effect wasca.30 times more effective than witnessed with single addition. This work focused on the synergistic effect brought about by nitrite and triethanolamine and its novel mechanism was also proposed.

Spectrophotometric Determination of Trace Iron by Using Its Catalytic Effect on the N-Phenylanthranilic Acid-Potassium Periodate Reaction

The analytical features of the reaction between N-phenylanthranilic acid (PAA) and potassium periodate in acidic medium are explored with the aim of improving the catalytic kinetic determination of iron in water samples. In the presence of Fe(II, III), PAA is oxidized by potassium periodate in a formic acid medium to form a violet-colored compound. The reaction is followed spectrophotometrically by measuring the increase in the absorbance of the oxidation product at 525 nm. The variables that affected the reaction rate were investigated and the reaction conditions were established. Calibration graphs are linear in the range of concentrations 2 - 500 ng mL(-1). As low as 10(-8) mol L(-1) Fe(II, III) can be easily determined by the fixed time method. The established catalytic method was successfully applied to the determination of iron in tap water and in pharmaceutical samples.

MultiSimplex optimization of on-line sorbent proconcentration and determination of iron by FI-AAS and microcolumn of immobilized ferron

A simple flow injection on-line separation and proconcentration system for determination of iron in milk and water samples were developed. Ferron was physically immobilized on alumina particles in the pH range of 2.5–6 and was used as sorbent in microcolumn preparation. Deposition of iron was effected by processing a standard or solution of analyte at pH range of 3–6 on the microcolumn. Injection of 300 μl of HNO 3 (5 mol l −1) served to elute the retained species to FAAS. Different factors affecting the performance of the system were optimized by MultiSimplex and univariable methods. MultiSimplex program based on the simplex algorithm allowed the simultaneous study of the variables affecting immobilization, sorption or elution process. The capacity of the sorbent under working condition was found to be 989.0 μg irons per gram of packing material. A sample volume of 20 and 40 ml resulted in preconcentration factors of 65 and 129, respectively. Precision ( n = 6) at 125 and 50 μg l −1 were 2.0 and 2.9%, respectively. With 20 ml sampling volume a detection limit of 1.06 μg l −1 was determined. The method was applied to determination of iron in tap water, river water, rain water, spring water, infant dry formula milk, human and cow milk. The accuracy was assessed through recovery experiments, independent analysis by furnace atomic absorption, and analysis of certified reference alloy.

A Sensitive Fluorescence Quenching Method for the Determination of Iron (II) with 1,10‐Phenanthroline

AbstractA sensitive and selective fluorescence quenching method for the determination of Fe2+ with 1,10‐phenanthroline was developed. The fluorescence intensity of 1,10‐phenanthroline at λex of 266 run and λem of 365 nm was constant in the range of pH 4.0 to 10.0 and decreased linearly upon addition of Fe2+ to its solution. This decrease was mainly due to a static quenching effect caused by the formation of a non‐fluorescent complex of Fe2+ with 1, 10‐phenanthroline. The total amount of iron was determined by using hydroxylamine hydrochloride to reduce Fe3+ to Fe2+. The linear range was from 5.0 × 10–7 to 2.0 × 10–5 mol/L with a detection limit of 2.4 × 10–8 mol/L at 3s̀. The quenching constant of Fe2+ to 1,10‐phenanthroline was calculated to be (5.70 × 0.05) × 104 L/mol at 25 °C. Effects of foreign ions on the determination of Fe2+ were investigated. The results of the new method for the determination of iron in tap water and natural water samples were in good agreement with those obtained by graphite atomic absorption spectrometry.

Flow-injection analysis of iron in tap water using its catalytic effect on the oxidation of an azo compound

1-Amino-8-hydroxy-7-(o-hydroxy-p-methylphenylazo)-3,6-naphthalenedisulfonic acid (p-CH3) reacts with KIO4 in an acid solution to form a colorless azoxy compound. The reaction was enhanced with iron(III). Therefore, a flow-injection analysis (FIA) of iron was investigated by measuring the decrease in the absorbance of p-CH3. The flow system used had three channels. Each carrier (distilled water), KIO4 solution as a oxidizing agent and reagent(p-CH3) solution was pumped at 1.0 cm3/min. A sample solution was injected manually into the carrier stream. Then, a p-CH3 solution containing sample was mixed with a KIO4 solution. Under the optimum conditions (temperature, 50°C; p-CH3, 1.2×10−4 M; KIO4, 1.0×10−5 M; HCl, 0.3 M; reaction coil length, 9 m, i.d. 1 mm; injection volume of sample, 1.0 cm3), Fe(III) could be determined in the concentration range of 1.4 to 16 ppb (ng cm−3) by monitoring at 556 nm. The detection limit of Fe(III) was 0.48 ppb (S/N=5). Also, 15 samples could be analyzed per hour. Mn(II), Cr(VI) and V(V) at more than 0.8-fold, 5-fold and 50-fold concentrations of Fe(III)(8 ppb) showed positive interferences, respectively. However, these metal ions did not interfere with the determination of iron in tap water. As a result, the proposed method was applied to the determination of iron in tap water without any masking agents. The results of a trace iron determination in tap water showed a good agreement with the values obtained by ICP-AES.

Determination of the total iron by chitosan-modified glassy carbon electrode

A new preconcentration and voltammetric method was developed for the determination of total Fe by a chitosan modified glassy carbon electrode (CMGCE). The measurements were carried out by cathodic stripping voltammetry. Using the instability of Fe(C 2O 4) 3 3− to light and the reductive effect of C 2O 4 2−, the method can be used to determinate total iron. The effects of several experimental parameters, such as pH, the concentration of the modifier, deposition potential, deposition time, scan rate and UV absorption curves were studied for analytical applications. A linear response was obtained in the concentration range 2×10 −8–3×10 −7 g/ml Fe with a detection limit of 1×10 −8 g/ml for a 2-min deposition time. A relative standard deviation (R.S.D.) of 3.67% was obtained for six determinations of 2×10 −7 g/ml Fe 3+. The method can be used to determine the total iron in tap water and mineral water directly.

Fluorimetric determination of iron using 5-(4-methoxyphenylazo)-8-(4-toluenesulfonamido)quinoline

A highly sensitive and relatively interference-free fluorimetric method for the determination of iron(III) is described. The method is based on the reaction between iron(III) and 5-(4-methoxyphenylazo)-8- (4-toluenesulfonamido)quinoline in the presence of cetyltrimethylammonium bromide. The fluorescence intensity (λex = 317 nm, λem = 534 nm) is linear up to 3 μM (170 ng ml−1) iron(III) in aqueous solution with a repeatability (RSD) of 3.2% at a concentration of 180 nM (10 ng ml−1) and a detection limit (3s) of 2 nM (0.12 ng ml−1). The influence of reaction variables and the effect of interfering ions are reported. The proposed procedure was applied to the determination of trace amounts of iron(III) and total iron in tap water, canal water and wine samples without the need for preconcentration, pre-separation or organic solvent extraction.

Kinetic spectrophotometric determination of trace iron (III) withp-amino-N,N-dimethylaniline dihydrochloride and hydrogen peroxide

A new, simple and highly sensitive kinetic method for the determination of trace iron (III) has been developed based on the catalytic effect of iron (III) on color reaction ofp-amino-N, N-dimethylaniline dihydrochloride (p-DMA) oxidated by hydrogen peroxide. The reaction is followed spectrophotometrically by measuring the absorbance at 510 nm. The detection limit is 4.47×10−11 g/ml, and the calibration curve is linear in the range of 0–0.10μg Fe(III) /25 ml with a relative standard deviation of ±3.25%. The method has been applied to the determination of iron in tap-water, chemical reagents and human hair.

Simple and rapid spectrophotometric determination of iron after preconcentration as its 1,10-phenanthroline complex on the natural polymer “chitin”

Preconcentration by collection of metal complexes on chitin has been applied to the spectrophotometric determination of iron in water. The iron is collected as its 1,10-phenanthroline (phen) complex on a column of chitin in the presence of tetraphenylborate as counter-ion. The iron(II)—phen complex retained on the chitin is eluted with an acetone—1 M acetic acid mixture (8:2 v/v), and the absorbance of the eluate is measured at 512 nm. Beer's law is obeyed over the concentration range 1.1–11.2 μg of iron in 10 ml of eluate. In the presence of EDTA as masking agent, Ca, Mg, Al, Mn, Zn, Cd and Pb do not interfere in concentrations up to 100 times that of iron(II) and Co, Ni and Cu do not interfere in concentrations up to 20 times that of iron(II). Common inorganic anions do not interfere in concentrations up to 10,000 times that of iron(II). The proposed method has been applied to determination of iron in tap water.

Determination of the polarization resistance from impedance measurements

AbstractFour different methods for determining the polarization resistance R from impedance data are discussed. These methods are suitable for online corrosion monitoring. Their use is illustrated for iron in tapwater and in neutral, aerated Na2SO4 containing various inhibitors. R‐values obtained with the CIRFIT‐method are compared with R which is obtained from a linear sweep through Ecorr. The integration method has the advantage of computation speed.

A computer analysis of electrochemical impedance data

CIRFIT, a computer analysis of electrochemical impedance data, minimizes the sum of squares of the radial difference between observed and calculated impedance data presented in either the complex impedance or admittance plane. CIRFIT requires no assumptions of ideal capacitive frequency response for the double layer in order to extract the values of solution resistance and polarization resistance that are important to corrosion rate analysis. Examples are presented of the use of CIRFIT for the analysis of corroding iron in tapwater and for model pit electrodes that have two time constants in 0.5 M NaCl.

Mechanism of Action of Acidified Sodium Phosphate Solution as a Corrosion Inhibitor of Iron in Tap Water

AbstractThe influence of phosphate as acid Na3PO4 solution in tap water was investigated using gravimetric and potentiostatic techniques. It was found that the phosphates are adsorbed in the form of positively charged colloidal particles on the cathodic areas of the metal. The degree of coverage, θ, vs log concentration of PO43− shows good agreement with Frumkin's isotherm in the form:θ/1−θ exp (−2.55θ) = 2530.CpO3−4 The calculated standard free energy of adsorption was found to be ∆ Gads° = −28·8 kJ.mol−1 (or −6·9 kcal.mol−1).

Mechanism of Action of Acidified Sodium Phosphate Solution as a Corrosion Inhibitor of Iron in Tap Water

Mechanism of Action of Acidified Sodium Phosphate Solution as a Corrosion Inhibitor of Iron in Tap Water