scholarly journals Modeling porosity loss in Fe0-based permeable reactive barriers with Faraday’s law

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Huichen Yang ◽  
Rui Hu ◽  
Hans Ruppert ◽  
Chicgoua Noubactep
Keyword(s):  
Surface Passivation ◽  
Corrosion Process ◽  
Corrosion Products ◽  
Permeable Reactive Barriers ◽  
Iron Surface ◽  
Iron Corrosion ◽  
Corrosion Rates ◽  
Faraday’S Law ◽  
Reactive Barriers ◽  
The Impact

AbstractSolid iron corrosion products (FeCPs), continuously generated from iron corrosion in Fe0-based permeable reactive barriers (PRB) at pH > 4.5, can lead to significant porosity loss and possibility of system’s failure. To avoid such failure and to estimate the long-term performance of PRBs, reliable models are required. In this study, a mathematical model is presented to describe the porosity change of a hypothetical Fe0-based PRB through-flowed by deionized water. The porosity loss is solely caused by iron corrosion process. The new model is based on Faraday’s Law and considers the iron surface passivation. Experimental results from literature were used to calibrate the parameters of the model. The derived iron corrosion rates (2.60 mmol/(kg day), 2.07 mmol/(kg day) and 1.77 mmol/(kg day)) are significantly larger than the corrosion rate used in previous modeling studies (0.4 mmol/(kg day)). This suggests that the previous models have underestimated the impact of in-situ generated FeCPs on the porosity loss. The model results show that the assumptions for the iron corrosion rates on basis of a first-order dependency on iron surface area are only valid when no iron surface passivation is considered. The simulations demonstrate that volume-expansion by Fe0 corrosion products alone can cause a great extent of porosity loss and suggests careful evaluation of the iron corrosion process in individual Fe0-based PRB.

Characterization of corrosion products in the permeable reactive barriers

2000 ◽  
Vol 40 (1-2) ◽  
pp. 184-194 ◽  
Author(s):  
Y. Roh ◽  
S. Y. Lee ◽  
M. P. Elless
Keyword(s):  
Corrosion Products ◽  
Permeable Reactive Barriers ◽  
Reactive Barriers

Corrosion of Iron and Migration of Corrosion Products in Compacted Bentonite

1994 ◽  
Vol 353 ◽  
Author(s):  
T. Kozaki ◽  
Y. Imamura ◽  
J. Takada ◽  
S. Sato ◽  
H. Ohashi
Keyword(s):  
Diffusion Coefficients ◽  
Corrosion Products ◽  
Iron Foil ◽  
Iron Corrosion ◽  
Apparent Diffusion Coefficients ◽  
Corrosion Rates ◽  
Compacted Bentonite ◽  
Apparent Diffusion ◽  
And Migration ◽  
High Level

AbstractFor safety assessment of the geological disposal of the high level radioactive waste, it is necessary to study corrosion of the overpack materials and migration of the corrosion products in the compacted bentonite. In the present study, average corrosion rates of iron foil and apparent diffusion coefficients of the corrosion products were determined using a neutron- activated iron foil. The average corrosion rates were on the order of 10-6m/y, while apparent diffusion coefficients were in the range from 10-12 to 10-14m2/s. No tendency to decrease in the corrosion rates with increasing corrosion time was observed. This suggests that the iron foil corrodes under reducing condition. Asymmetric concentration profiles of iron corrosion products were obtained in some experiments. It can be considered that either cathodic or anodic reaction would dominantly occur on one side of the iron foil surfaces and that each reaction would change the pH in pore water of bentonite specimens adjacent to the iron foil surfaces.

scholarly journals Vapour Phase Deposition of Thin Siloxane Coatings on the Iron Surface. The Impact of the Layer Structure and Oxygen Adsorption on Corrosion Stability

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1217
Author(s):  
Andrei Nazarov ◽  
Maxim Petrunin ◽  
Liudmila Maksaeva ◽  
Tatyana Yurasova ◽  
Pierluigi Traverso ◽  
...  
Keyword(s):  
Corrosion Protection ◽  
Sulphur Dioxide ◽  
Layer Structure ◽  
Vapour Phase ◽  
Oxygen Adsorption ◽  
Iron Surface ◽  
Iron Corrosion ◽  
Corrosion Stability ◽  
The Impact ◽  
Vapour Phase Deposition

The mechanism of iron corrosion protection by thin siloxane films was clarified. Quartz crystal microbalance technique (QCM) was applied to control the vapour phase deposition of alkoxysilanes and the formation of thin siloxane films. It was shown that the addition of water vapour increased the thickness of the grafted siloxane films. Crystal-like films spontaneously grow to 10–16 monolayers at 100% RH of Ar flow due to the catalytic effect of the surface. X-ray photoelectron (XPS) and Auger spectroscopies analysed the thin siloxane films and Scanning Kelvin Probe (SKP) showed the formation of iron-siloxane bonds passivating the iron surface. The films showed high hydrophobicity and corrosion inhibition in humid air contaminated by sulphur dioxide. Thick films were less ordered, hydrophilic and accelerated the corrosion of iron. For corrosion protection, the presence of oxygen in the atmosphere is extremely important. In a wet Ar atmosphere, contaminated by sulphur dioxide, the surfaces are not stable and quickly corroded. Oxygen adsorption stabilizes the surface oxide film that correspondingly preserves the anchoring iron-siloxane bonds and enables corrosion protection by the coating.

Investigation of atmospheric corrosion with use of permanent corrosion stations

2012 ◽  
Vol 30 (1) ◽  
pp. 25-44 ◽  
Author(s):  
Piotr Barszcz
Keyword(s):  
Atmospheric Corrosion ◽  
Field Tests ◽  
Research Process ◽  
Technical Condition ◽  
Corrosion Process ◽  
Corrosion Products ◽  
Physical Parameters ◽  
Atmospheric Conditions ◽  
The Impact

Field tests of atmospheric corrosion [7, 14, 15] are understood as investigation that are carried out in the Earth atmosphere at the ambient temperature in order to determine corrosion resistance of metals and pollution of environment by corrosion products, efficiency of corrosion protection or corrosion aggressiveness of environment [9, 11]. The investigation dedicated to prolongation of the technical service time of aircrafts as well implementation of their operation according to their actual technical condition are closely connected to investigation of corrosion processes under natural atmospheric conditions where specimens of materials are exposed to the impact of ambient factors and periodically subjected to tests that assume visual inspection, scheduled determination of weight and volume loss due to corrosion, appearance of specimens and alteration of their physical parameters [4]. Investigation results are obtained as measurements of weight and thickness of corroded specimens, photographs of specimen surfaces after withdrawing them back from the corrosion stations and removing corrosion products. On the basis of information acquired from investigations on corrosion it is possible to calculate parameters that are specific for the corrosion process that takes place within the region where a permanent corrosion station is located. The calculated parameters have been sourced from standards that are effective in Poland and worldwide [5, 6, 8, 10] but own specifications have also been developed based on the gained experience (Table 3). The research process involves also monitoring of atmospheric conditions that exist on the area where corrosion specimens are exposed [4]. Information related to atmospheric conditions is sourced from the Hydrometeorological Centre of Polish Army along with information that is published on the Internet by the Inspectorate of Environmental Protection. These information that reflect the atmospheric conditions make it possible to seek for the correlation between the parameters that are specific for the corrosion process and meteorological conditions.

scholarly journals Carbothermal Synthesis of Ni/Fe Bimetallic Nanoparticles Embedded into Graphitized Carbon for Efficient Removal of Chlorophenol

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1417
Author(s):  
Min Zhuang ◽  
Wen Shi ◽  
Hui Wang ◽  
Liqiang Cui ◽  
Guixiang Quan ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Surface Passivation ◽  
Bimetallic Nanoparticles ◽  
Zero Valent Iron ◽  
Molar Ratio ◽  
Particle Sizes ◽  
Iron Corrosion ◽  
Graphitized Carbon ◽  
Nanoscale Zero Valent Iron ◽  
Iron Nickel

The reactivity of nanoscale zero-valent iron is limited by surface passivation and particle agglomeration. Here, Ni/Fe bimetallic nanoparticles embedded into graphitized carbon (NiFe@GC) were prepared from Ni/Fe bimetallic complex through a carbothermal reduction treatment. The Ni/Fe nanoparticles were uniformly distributed in the GC matrix with controllable particle sizes, and NiFe@GC exhibited a larger specific surface area than unsupported nanoscale zero-valent iron/nickel (FeNi NPs). The XRD results revealed that Ni/Fe bimetallic nanoparticles embedded into graphitized carbon were protected from oxidization. The NiFe@GC performed excellently in 2,4,6-trichlorophenol (TCP) removal from an aqueous solution. The removal efficiency of TCP for NiFe@GC-50 was more than twice that of FeNi nanoparticles, and the removal efficiency of TCP increased from 78.5% to 94.1% when the Ni/Fe molar ratio increased from 0 to 50%. The removal efficiency of TCP by NiFe@GC-50 can maintain 76.8% after 10 days of aging, much higher than that of FeNi NPs (29.6%). The higher performance of NiFe@GC should be ascribed to the significant synergistic effect of the combination of NiFe bimetallic nanoparticles and GC. In the presence of Ni, atomic H* generated by zero-valent iron corrosion can accelerate TCP removal. The GC coated on the surface of Ni/Fe bimetallic nanoparticles can protect them from oxidation and deactivation.

Sign in / Sign up

Export Citation Format

Share Document