scholarly journals A Novel and Facile Method to Characterize the Suitability of Metallic Iron for Water Treatment

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2465 ◽  
Author(s):  
Mesia Lufingo ◽  
Arnaud Igor Ndé-Tchoupé ◽  
Rui Hu ◽  
Karoli N. Njau ◽  
Chicgoua Noubactep
Keyword(s):  
Ascorbic Acid ◽  
Water Treatment ◽  
Metallic Iron ◽  
Ethylenediaminetetraacetic Acid ◽  
Complexing Agents ◽  
Iron Corrosion ◽  
Dissolved Iron ◽  
The One ◽  
Intrinsic Reactivity ◽  
Dissolved O2

Metallic iron (Fe0) materials have been industrially used for water treatment since the 1850s. There are still many fundamental challenges in affordably and reliably characterizing the Fe0 intrinsic reactivity. From the available methods, the one using Fe0 dissolution in ethylenediaminetetraacetic acid (EDTA—2 mM) was demonstrated the most applicable as it uses only four affordable chemicals: Ascorbic acid, an ascorbate salt, EDTA and 1,10-Phenanthroline (Phen). A careful look at these chemicals reveals that EDTA and Phen are complexing agents for dissolved iron species. Fe3-EDTA is very stable and difficult to destabilize; ascorbic acid is one of the few appropriate reducing agents, therefore. On the other hand, the Fe2-Phen complex is so stable that oxidation by dissolved O2 is not possible. This article positively tests Fe0 (0.1 g) dissolution in 2 mM Phen (50 mL) as a characterization tool for the intrinsic reactivity, using 9 commercial steel wool (Fe0 SW) specimens as probe materials. The results are compared with those obtained by the EDTA method. The apparent iron dissolution rate in EDTA (kEDTA) and in Phen (kPhen) were such that 0.53 ≤ kEDTA (μg h−1) ≤ 4.81 and 0.07 ≤ kPhen (μg h−1) ≤ 1.30. Higher kEDTA values, relative to kPhen, are a reflection of disturbing Fe3 species originating from Fe2 oxidation by dissolved O2 and dissolution of iron corrosion products. It appears that the Phen method considers only the forward dissolution of Fe0. The Phen method is reliable and represents the most affordable approach for characterizing the suitability of Fe0 for water treatment.

scholarly journals Characterizing the Suitability of Granular Fe0 for the Water Treatment Industry

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 652 ◽  
Author(s):  
Rui Hu ◽  
Xuesong Cui ◽  
Minhui Xiao ◽  
Pengxiang Qiu ◽  
Mesia Lufingo ◽  
...  
Keyword(s):  
Water Treatment ◽  
Ethylenediaminetetraacetic Acid ◽  
Batch Experiments ◽  
Iron Corrosion ◽  
Experimental Conditions ◽  
Initial Stage ◽  
Intrinsic Reactivity ◽  
First Time ◽  
Kinetics Of

There is a burgeoning interest in reliably characterizing the intrinsic reactivity of metallic iron materials (Fe0) or zero-valent iron materials (ZVI) used in the water treatment industry. The present work is a contribution to a science-based selection of Fe0 for water treatment. A total of eight (8) granular ZVI materials (ZVI1 to ZVI8) were tested. Fe0 dissolution in ethylenediaminetetraacetic acid (EDTA test) and 1,10-Phenanthroline (Phen test) is characterized in parallel experiments for up to 250 h (10 days). 50 mL of each solution and 0.1 g of each Fe0 material are equilibrated in quiescent batch experiments using 2 mM EDTA or Phen. Results indicated a far higher extent of iron dissolution in EDTA than in Phen under the experimental conditions. The tested materials could be grouped into three reactivity classes: (i) low (ZVI4, ZVI6, ZVI7, and ZVI8), (ii) moderate (ZVI1 and ZVI5) and (iii) high (ZVI2 and ZVI3). The order of reactivity was the same for both tests: ZVI2 ≅ ZVI3 > ZVI1 ≅ ZVI5 > ZVI4 ≅ ZVI6 ≅ ZVI7 ≅ ZVI8. Phen results revealed for the first time the time-dependent variation of the kinetics of iron corrosion (corrosion rate) in short-term batch experiments. Overall, the results demonstrated the superiority of the Phen test for evaluating the initial stage of Fe0 dissolution. Long-term column experiments are recommended to deepen the acquired knowledge.

scholarly journals Redirecting Research on Fe0 for Environmental Remediation: The Search for Synergy

2019 ◽  
Vol 16 (22) ◽  
pp. 4465 ◽  
Author(s):  
Hu ◽  
Noubactep
Keyword(s):  
Water Treatment ◽  
Metallic Iron ◽  
Environmental Remediation ◽  
Cathodic Reaction ◽  
Contaminant Removal ◽  
Iron Corrosion ◽  
Basic Relationship ◽  
Kinetics Of ◽  
Center Research

A survey of the literature on using metallic iron (Fe0) for environmental remediation suggests that the time is ripe to center research on the basic relationship between iron corrosion and contaminant removal. This communication identifies the main problem, which is based on the consideration that contaminant reductive transformation is the cathodic reaction of iron oxidative dissolution. Properly considering the inherent complexities of the Fe0/H2O system will favor an appropriate research design that will enable more efficient and sustainable remediation systems. Successful applications of Fe0/H2O systems require the collective consideration of progress achieved in understanding these system. More efforts should be made to decipher the long-term kinetics of iron corrosion, so as to provide better approaches to accurately predict the performance of the next generation Fe0-based water treatment systems.

Water treatment to reduce internal corrosion in the drinking water distribution system in Oslo

2001 ◽  
Vol 1 (3) ◽  
pp. 91-96 ◽  
Author(s):  
L.J. Hem ◽  
E.A. Vik ◽  
A. Bjørnson-Langen
Keyword(s):  
Water Treatment ◽  
Corrosion Rate ◽  
Distribution System ◽  
Water Distribution ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Corrosion Monitoring ◽  
Copper Corrosion ◽  
Iron Corrosion ◽  
Internal Corrosion

In 1995 the new Skullerud water treatment plant was put into operation. The new water treatment includes colour removal and corrosion control with an increase of pH, alkalinity and calcium concentration in addition to the old treatment, which included straining and chlorination only. Comparative measurements of internal corrosion were conducted before and after the installation of the new treatment plant. The effect of the new water treatment on the internal corrosion was approximately a 20% reduction in iron corrosion and a 70% reduction in copper corrosion. The heavy metals content in standing water was reduced by approximately 90%. A separate internal corrosion monitoring programme was conducted, studying the effects of other water qualities on the internal corrosion rate. Corrosion coupons were exposed to the different water qualities for nine months. The results showed that the best protection of iron was achieved with water supersaturated with calcium carbonate. Neither a high content of free carbon dioxide or the use of the corrosion inhibitor sodium silicate significantly reduced the iron corrosion rate compared to the present treated water quality. The copper corrosion rate was mainly related to the pH in the water.

scholarly journals Testing Metallic Iron Filtration Systems for Decentralized Water Treatment at Pilot Scale

Water ◽  
2015 ◽  
Vol 7 (12) ◽  
pp. 868-897 ◽  
Author(s):  
Raoul Tepong-Tsindé ◽  
Richard Crane ◽  
Chicgoua Noubactep ◽  
Achille Nassi ◽  
Hans Ruppert
Keyword(s):  
Water Treatment ◽  
Metallic Iron ◽  
Pilot Scale

scholarly journals Metallic iron for water treatment: leaving the valley of confusion

2017 ◽  
Vol 7 (8) ◽  
pp. 4177-4196 ◽  
Author(s):  
Susanne Makota ◽  
Arnaud I. Nde-Tchoupe ◽  
Hezron T. Mwakabona ◽  
Raoul Tepong-Tsindé ◽  
Chicgoua Noubactep ◽  
...  
Keyword(s):  
Water Treatment ◽  
Metallic Iron

scholarly journals Metallic Iron for Water Treatment: A Critical Review

2013 ◽  
Vol 41 (7) ◽  
pp. 702-710 ◽  
Author(s):  
Chicgoua Noubactep
Keyword(s):  
Water Treatment ◽  
Critical Review ◽  
Metallic Iron

Trace determination of gadolinium by conductivity-based approach

2020 ◽  
Vol 98 (10) ◽  
pp. 652-658
Author(s):  
R. Ananthanarayanan ◽  
M. Sivaramakrishna ◽  
B.S. Panigrahi
Keyword(s):  
Heavy Water ◽  
Ethylenediaminetetraacetic Acid ◽  
Limit Of Detection ◽  
Nuclear Industry ◽  
Complexing Agents ◽  
Complexing Agent ◽  
High Performing ◽  
New Class ◽  
Water Reactors

A conductivity-based technique is developed for the determination of Gd3+ in the heavy water moderators of pressurized heavy water reactors (PHWRs). The method involves monitoring extremely small shifts in conductivity, in the order of few nS/cm, due to the continuous addition of a suitable complexing agent to Gd3+ in aqueous medium. The resulting plot gives two distinct regions with vastly differing slopes. Two multidentate ligands, ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaaceticacid (DTPA), as complexing agents are compared. A high performing conductivity detector based on a new class of sensors called pulsating sensors that works entirely in the digital domain is deployed to monitor the conductivity shifts. Titration plots are studied in both H2O and D2O, and the observed difference between the plots in the two matrices is discussed in detail. Boron did not interfere in the analysis. The method was validated using the UV–vis spectrophotometric technique. The method is sensitive and rapid, as each analysis takes 3 min. The limit of detection in H2O and D2O are 1.27×10−7 mol/L and 5.1×10−7 mol/L, respectively. The precision in analysis lies between 1.9% and 5.3%. This method has important application in the nuclear industry for the routine analysis of gadolinium.

scholarly journals An iron budget during the natural iron fertilisation experiment KEOPS (Kerguelen Islands, Southern Ocean)

2009 ◽  
Vol 6 (4) ◽  
pp. 6803-6837 ◽  
Author(s):  
F. Chever ◽  
G. Sarthou ◽  
E. Bucciarelli ◽  
S. Blain ◽  
A. R. Bowie
Keyword(s):  
Southern Ocean ◽  
Dissolved Iron ◽  
Heard Island ◽  
Natural Iron ◽  
Particulate Iron ◽  
The Difference ◽  
The One ◽  
Iron Pool ◽  
Lateral Advection ◽  
Very High

Abstract. Total dissolvable iron (TDFe) was measured in the water column above and in the surrounding of the Kerguelen Plateau (Indian sector of the Southern Ocean) during the KErguelen Ocean Plateau compared Study (KEOPS) cruise. TDFe concentrations ranged from 0.90 to 65.6 nmol L−1 above the plateau and from 0.34 to 2.23 nmol L−1 offshore of the plateau. Station C1 located south of the plateau, near Heard Island, exhibited very high values (329–770 nmol L−1). Apparent particulate iron (Feapp), calculated as the difference between the TDFe and the dissolved iron measured on board (DFe) represented 95±5% of the TDFe above the plateau, suggesting that particles and refractory colloids largely dominated the iron pool. This paper presents a budget of DFe and Feapp above the plateau. Lateral advection of water that had been in contact with the continental shelf of Heard Island seems to be the predominant source of Feapp and DFe above the plateau, with a supply of 9.7±2.3×106 and 8.3±6.7×103 mol d−1, respectively. The residence times of 1.7 and 48 days estimated for Feapp and DFe, respectively, indicate a rapid turnover in the surface water. A comparison between Feapp and total particulate iron (TPFe) suggests that the total dissolved fraction is mainly constituted of small refractory colloids. This fraction does not seem to be a potential source of iron to the phytoplankton in our study. Finally, when taking into account the lateral supply of dissolved iron, the seasonal carbon sequestration efficiency was estimated at 154 000 mol C (mol Fe)−1, which is 4-fold lower than the previously estimated value in this area but still 18-fold higher than the one estimated during the other study of a natural iron fertilisation experiment, CROZEX.

Determination of Ascorbic Acid Based on a Platinum Nanoparticles Modified Au Electrode

2011 ◽  
Vol 110-116 ◽  
pp. 1732-1735
Author(s):  
Jia Hong He ◽  
Qiang Xu ◽  
Zhong Rong Song ◽  
Hai Yan Kuang
Keyword(s):  
Electron Microscopy ◽  
Ascorbic Acid ◽  
Modified Electrode ◽  
Platinum Nanoparticles ◽  
Reaction System ◽  
Au Electrode ◽  
Transmission Electron ◽  
Growth Method ◽  
One Step ◽  
The One

A Platinum nanoparticles modified Au electrode has been successfully fabricated by using an in situ growth method. In this method, the Platinum nanoparticles could be grown on the Au electrode surface via the one-step immersion into the mixture of H2PtCl6 (analytical grade, 1g/L), NaBH4 (analytical grade) and polyvinylpyrrolidone K30 (PVP, analytical grade). A certain amount of PVP was added into the reaction system to prevent the coagulation of the Platinum nanoparticles, which obtained by the chemical redox reaction of H2PtCl6 and NaBH4. The structures and morphologies of the Platinum nanoparticles were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) . The direct electrochemical behavior of ascorbic acid in 0.3 mol/L NaCl medium at the Platinum nanoparticles modified electrode has been investigated in detail. Compared to a bare Au electrode, a substantial decrease in the overvoltage of the ascorbic acid was observed at the Platinum nanoparticles modified electrode with oxidation starting at ca. 0.20 V vs. SCE (saturated KCl). At an applied potential of 0.18V, this modified electrode produced high and reproducible sensitivity to ascorbic acid and linear responses were obtained over a concentration range from 0.600 to 3.267 μmol/L with a detection limit of 1.9 nmol/L(S/N=3). The fabrication method of this sensor, which has highly sensitive, low working potential, and fast amperometric sensing to ascorbic acid, is simple and without using complex equipment. In addition, the sensor has been successfully used to detect ascorbic acid in real sample, thus is promising for the future development of ascorbic acid sensors.

scholarly journals Analysis and assessment of water treatment plant reliability

2017 ◽  
Vol 41 (1) ◽  
pp. 21-38
Author(s):  
Dawid Szpak ◽  
Barbara Tchórzewska-Cieślak
Keyword(s):  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Parameter Method ◽  
Flow Sheet ◽  
Surface Water Treatment ◽  
The Subject ◽  
Availability Index ◽  
The One ◽  
The Individual

Abstract The subject of the publication is the analysis and assessment of the reliability of the surface water treatment plant (WTP). In the study the one parameter method of reliability assessment was used. Based on the flow sheet derived from the water company the reliability scheme of the analysed WTP was prepared. On the basis of the daily WTP work report the availability index Kg for the individual elements included in the WTP, was determined. Then, based on the developed reliability scheme showing the interrelationships between elements, the availability index Kg for the whole WTP was determined. The obtained value of the availability index Kg was compared with the criteria values.

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