Corrosion Of Iron In Water Research Articles

Bibliographical Synthesis on the Corrosion and Protection of Archaeological Iron by Green Inhibitors

Iron is a widely used metal due to its low cost and availability, but it is susceptible to corrosion in many circumstances. This corrosion can result in economic and environmental losses, and negatively affect the physical and chemical properties of the metal. This chapter provides a background on iron corrosion in archaeology and introduces various inhibitors used for its protection. It starts with a general overview of corrosion and metallurgy of iron, followed by an in-depth explanation of the mechanisms of iron corrosion in water and air. The chapter concludes with a review of different corrosion inhibitors, focusing on those made from natural plant extracts.

Evaluating Deposit Formation of Iron-Corrosion Products in High- and Low-Pressure Evaporative Circuits When Starting a Combined-Cycle Plant

One of the main causes of equipment damage at TPPs is corrosion of structural materials and deposit formation on the heat-transfer surfaces of the steam-water tract. This process occurs during stationary operation of the equipment and during start-ups and shutdowns of the power unit. In this paper, we assess the deposit formation of corrosion products in the evaporative circuits during the start-up of a combined cycle plant with the subsequent prediction of the number of starts after which it is necessary to carry out a chemical washing of the boiler-utilizer. The changes in the product concentration of iron corrosion in water and steam when starting a 450-MW power unit from a cold state are shown. The probability for the deposit formation of iron-corrosion products is estimated based on the experimental data obtained at start-up, with the subsequent calculation of the material balance for iron-corrosion products for low- and high-pressure circuits. A comparative analysis of the probability for deposit formation of iron-corrosion products in the high- and low-pressure circuits during the start-up period and at nominal operating parameters is performed. As a result of studies, it was found that the iron concentration in the feed and boiler water and saturated steam of the high- and low-pressure circuit significantly exceeds the normalized values by the time when the boiler-utilizer reaches its operating parameters. The specific amount of iron-corrosion products that can be deposited on heat-transfer surfaces in one start for the low- and high-pressure circulation circuit is determined. To reduce the probability for deposits of corrosion products during start-up, it is proposed to use feed water with a lower iron concentration or to increase the purge of the boiler-utilizer. Recommendations on the shutdown of the boiler-utilizer for washing when the maximal specific deposit amount of 200 g/m2 is reached taking into account the number of permissible starts for the low-pressure circuit are given.

Preparation of palladized carbon nanotubes encapsulated iron composites: highly efficient dechlorination for trichloroethylene and low corrosion of nanoiron.

A method developed based on the capillary effect and capillary condensation theory was used to synthesize an innovative Fe/C/Pd composite in this study. This composite (Fe@CNTs@Pd) consists of carbon nanotubes (CNTs) with nanoscale zerovalent iron (NZVI) on the inner surface and palladium nanoparticles supported on the outer surface of CNTs. This structure successfully addresses the problems of high iron corrosion rate and lower utilization rate of hydrogen in the application of bimetal nanoparticles for trichloroethylene (TCE) removal. TCE degradation experiments and electrochemical tests were conducted to investigate the material properties and reaction mechanisms of the composite. It is found that the prepared composite material contribute a high level of TCE dechlorination rate and substantially reduced hydrogen production during iron corrosion in water compared with the conventional CNTs-supported bimetal materials (Fe/Pd@CNTs). Hydrogen spillover effect helps the reactivity of Fe@CNTs@Pd for TCE degradation and suppressed the galvanic cell effect, which results in a stronger resistance to corrosion. Although the Kobs of Fe@CNTs@Pd was 16.87% lower than that of Fe/Pd@CNTs, the hydrogen production rate of Fe@CNTs@Pd was 10 times slower than that of Fe/Pd@CNTs. Therefore, Fe@CNTs@Pd shows a significant reduction in the corrosion rate at a cost of slightly slower degradation of TCE. In sum, the prepared composites demonstrate important characteristics, including alleviating NZVI agglomeration, maintaining high TCE removal efficiency and reducing the corrosion of NZVI.

Corrosion protection of iron in water by activated carbon fiber (ACF)

Commercial activated carbon fiber (ACF) was modified and employed to prevent iron corrosion in industrial water supply and circulation system. Static and dynamic experiments were carried out under varying conditions, including different pHs, different temperatures, different adsorbent quantities and different adsorbents. The primary objective was to experimentally demonstrate the suitability of ACF in effectively preventing iron corrosion in water under varying operating conditions, and compare its performance vis-à-vis to that of the other commercially available adsorbents, such as granular activated carbon (GAC) and powdered activated carbon (PAC). Iron sheet static corrosion simulation test as well as dynamic corrosion simulation test was performed to verify the idea. It was found out that ACF could significantly decrease the zeta potential (from 329 mV to 203 mV when 100 mg ACF was added to 200 ml water) and dissolved oxygen concentration (from 9.60 mg/l to around 9.18 mg/l when 200 mg ACF was added to 200 ml water) of the solution, thereby slowing down iron corrosion rate.

Effect of Phosphate Concentration on the Corrosion of Iron in Water—Polyethylene Glycol Mixtures

Abstract Various electrochemical measurement techniques (polarization, electrochemical impedance spectroscopy [EIS], and electrochemical quartz microbalance [EQCM]) and accelerated corrosion tests were used to show that phosphates can be used as iron corrosion inhibitors in 20% polyethylene glycol (PEG 400) solutions. Their action mechanisms were found to modify the anodic behavior of the iron. In solutions with low-phosphate concentrations (<5 × 10−3 M), an iron oxide film formed, as in the case of aqueous solutions. But this oxide film did not provide protection and pitting occurred. At a phosphate concentration of 5 × 10−3 M or more, the iron was protected but by a film that was different from the one observed in aqueous solutions. A deposit, composed of PEG and phosphates, adsorbed preferentially on the anodic sites of the iron.

Mechanism of iron corrosion in water–polyethylene glycol (PEG 400) mixtures

The properties of water–polyethylene glycol (PEG 400) solutions vary with the PEG content. The highest acidity and conductivity values were observed in 20% PEG 400 solutions. Oxygen solubility in such solutions decreased as the PEG 400 content increased. Adsorption of PEG 400, estimated by EQCM, varied with the PEG 400 concentration, also reaching a maximum in 20% PEG 400 solutions, with the weight of the adsorbed layer reaching 3.5 μg cm −2. Iron corrosion in water–PEG 400 solutions was studied by monitoring the corrosion potential and the polarization curves. Iron corrosion was highest in the 20% PEG 400 solution due to the compromise between the evolution of acidity, dissolved oxygen content and the adsorption and complexation properties of the PEG solutions. Through adaptation of the Bockris mechanism, PEG adsorption at the metal surface constituted the first stage in the iron corrosion mechanism. Iron (ions)/PEG complexes were then formed, which diffused in solution.

A Mössbauer spectroscopy study of the corrosion of nodular cast iron in mine waters

The corrosion of ductile cast iron in water containing different amounts of chloride ions was investigated under both static and dynamic conditions. Corrosion/time relationships were established for exposure times of up to 30 days. Post-corrosion investigations were performed, employing Mossbauer spectroscopy, optical microscopy and electrochemical techniques. It was found that the nature of the surface corrosion product formed under static conditions differed morphologically and chemically from that formed under dynamic conditions. The latter was a hard layer consisting of a mixture of γ- and β-FeOOH (situated on an underlying cementite layer), whereas the static tests resulted in a soft, spongy corrosion product, identified as β-FeOOH.

淡水中の鉄腐食に対するアルミニウムイオンの腐食抑制作用

An interruption by sulfate ion on the inhibitive effect of aluminium ion for iron corrosion in water has been investigated. The inhibitive effect of aluminium ion was found to be markedly deteriorated when the water contained sulfate ion. In the absence of sulfate ion, a thin and compact protective film of hydrated aluminium hydroxide was formed on the surface of the specimen during the corrosion, while in the presence of sulfate ion a dense film with many cracks of polynuclear sulfatecontaining oxy-aluminium complex was found to be formed, which caused a considerable deterioration of the inhibitive effect of aluminium ion. In order to overcome this defect, many additives that act co-operatively with aluminium ion were examined, whereby 2-mercaptobenzothiazole and some related compounds were found to be very effective.

The aluminium ion as a corrosion inhibitor for iron in water

The aluminium ion was found to be an effective inhibitor for iron corrosion in water in the pH range 4.1–4.5. The effect was ascribed to the formation of a thin hydrous aluminium oxide film on the iron surface which insulates the iron from the solution. This inhibitor is characterized by high inhibitive power even under stagnant conditions as well as flowing ones.

The aluminium ion as a corrosion inhibitor for iron in water

The aluminium ion was found to be an effective inhibitor for iron corrosion in water in the pH range 4.1–4.5. The effect was ascribed to the formation of a thin hydrous aluminium oxide film on the iron surface which insulates the iron from the solution. This inhibitor is characterized by high inhibitive power even under stagnant conditions as well as flowing ones.