scholarly journals A Revisit to the Corrosion Inhibition of Aluminum in Aqueous Alkaline Solutions by Water-Soluble Alginates and Pectates as Anionic Polyelectrolyte Inhibitors

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Refat Hassan ◽  
Ishaq Zaafarany ◽  
Adil Gobouri ◽  
Hideo Takagi
Keyword(s):  
Adsorption Mechanism ◽  
Inhibition Efficiency ◽  
Geometrical Structure ◽  
Physical Adsorption ◽  
Water Soluble ◽  
Alkaline Media ◽  
Alkaline Solutions ◽  
Corrosion Mechanism ◽  
Natural Polymer ◽  
Freundlich Isotherms

The corrosion behavior of aluminum (Al) in alkaline media in presence of some natural polymer inhibitors has been reinvestigated. The inhibition action of the tested inhibitors was found to obey both Langmuir and Freundlich isotherms models. The inhibition efficiency was found to increase with increasing the inhibitors concentration and decrease with increasing the temperature, suggesting physical adsorption mechanism. Factors such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and temperature affecting the corrosion rates were examined. The kinetic parameters were evaluated, and a suitable corrosion mechanism consistent with the kinetic results obtained is suggested and discussed.

The Adsorption Behavior of Modified Peanut Shells for Cr (VI)

2013 ◽  
Vol 781-784 ◽  
pp. 2189-2194
Author(s):  
Yi Hua Jiang ◽  
Xin Long Jiang
Keyword(s):  
Adsorption Mechanism ◽  
Physical Adsorption ◽  
Peanut Shell ◽  
Chemical Adsorption ◽  
Chemical Methods ◽  
Ir Spectrometry ◽  
Freundlich Isotherms ◽  
Reduction Processes ◽  
Peanut Shells ◽  
Adsorption Activation Energy

The adsorption of Cr(VI) by modified peanut shell has been investigated using chemical methods and IR spectrometry. The optimal condition for the adsorption of Cr(VI) by modified peanut shell is at 308 K and pH = 1.0, which gives a static saturated adsorption capacity of 14.15 mg·g-1, an apparent adsorption rate constant of k298 = 2.43 × 10-4 s-1, and an apparent adsorption activation energy of 10.58 kJ·mol-1. The adsorption follows the Langmuir and Freundlich isotherms and the liquid film diffusion is the controlling process of the adsorption. The adsorption thermodynamic parameters are ΔH = 125.58 kJ·mol-1, ΔS = 0.473 9 kJ·mol-1·K-1, ΔG = -17.81– -27.27 kJ·mol-1. Small amount of desorption is observed only at pH > 11. Adsorption mechanism of modified peanut shells for Cr(VI) was both physical adsorption and chemical adsorption of adsorbent "adsorption-oxidation and reduction processes".

QSAR Study of the Adsorption Mechanism of Ascorbic Acid towards Iron in Alkaline Media

2013 ◽  
Vol 652-654 ◽  
pp. 1585-1588
Author(s):  
Hui Wen Tian ◽  
Wei Hua Li ◽  
Bao Rong Hou
Keyword(s):  
Ascorbic Acid ◽  
Adsorption Mechanism ◽  
Inhibition Efficiency ◽  
Quantitative Structure Activity Relationship ◽  
Alkaline Media ◽  
Chemical Adsorption ◽  
Qsar Study ◽  
Structure Activity ◽  
Multivariate Nonlinear Regression ◽  
Corrosion Inhibition Efficiency

A significant correlation was obtained between corrosion inhibition efficiency and the molecular structure of ascorbic acid, using the Quantitative Structure Activity Relationship (QSAR) approach based on a multivariate nonlinear regression technique. It is proposed that inhibitor molecules attach to iron surface by means of chemical adsorption. The considerations leading to this assumption were confirmed by ATR FTIR spectroscopy.

scholarly journals PHYTOCHEMICALS AND INHIBITIVE PROPERTIES OF CASHEW EXTRACT AS CORROSION INHIBITOR OF ALUMINIUM IN H2SO4 MEDIUM

2019 ◽  
Vol 49 (2) ◽  
pp. 99-103
Author(s):  
M. OMOTIOMA ◽  
O. D. ONUKWULI ◽  
I. OBIORA- OKAFO
Keyword(s):  
Corrosion Inhibitor ◽  
Corrosion Inhibition ◽  
Adsorption Mechanism ◽  
Inhibition Efficiency ◽  
Physical Adsorption ◽  
Control Process ◽  
Quadratic Model ◽  
Qualitative And Quantitative ◽  
Quantitative Analyses ◽  
High Inhibition

This work studied the phytochemicals and inhibitive properties of cashew extract as corrosion inhibitor of aluminium in H2SO4 medium. Qualitative and quantitative analyses of the cashew extract were carried out to identify and quantify the phytochemicals for the corrosion inhibition process. Thermometric and gravimetric techniques were employed in the study of corrosion inhibition of aluminium in H2SO4 medium. The inhibition efficiency of the cashew extract was modeled using Response Surface Methodology (RSM) of Design Expert Software 9. It was revealed that phytochemicals of alkaloids, cardiac glycosides, flavonoids, phenolics, phytates, saponins and tanins were present in the cashew extract at various degrees. The cashew extract is predominantly made of flavonoids (425.0mg/100g) followed by alkaloids (221.7mg/100g).Adsorption of the cashew extract on the Al surface obeyed physical adsorption mechanism. Thermometric and gravimetric techniques are in agreement of recording high inhibition efficiencies of 83.7% and 82.5% respectively. The phytochemicals of the cashew extract are good inhibitive agents for the corrosion control process. A quadratic model is adequate for the description of the inhibition efficiency of the cashew extract as a function of inhibitor concentration, temperature and time.

scholarly journals Phytoconstituents of Methanolic Extract of Fenugreek Seeds as a Green Corrosion Inhibitor of Metals (Fe, Al and Cu)

2021 ◽  
Vol 4 (Vol4) ◽  
pp. 24-30
Author(s):  
Ghassab Al-Mazaideh
Keyword(s):  
Corrosion Inhibition ◽  
Chemical Structure ◽  
Adsorption Mechanism ◽  
Inhibition Efficiency ◽  
Physical Adsorption ◽  
Significant Inhibition ◽  
Metal Corrosion ◽  
Electrophilicity Index ◽  
Green Corrosion Inhibitor ◽  
Gibbs Process

DFT calculations were carried out on significant Fenugreek seed compounds (1-Methylpyridinium-3-carboxylate MPC, Apigenin-8-C-glucose ACG, and 2-Isobutyl-3-methoxypyrazine IBMP) as a green source of ecologically friendly Fe, Al, and Cu metal corrosion inhibitors. Complete geometry optimizations were performed by DFT-B3LYP/6-31G* to determine any relationship between the chemical structure and corrosion inhibition, mostly on metals' surfaces. Global computational parameters of the inhibitors and thermodynamic Gibbs process of adsorption of metals were calculated and used to evaluate each corrosion inhibitor's performance. Our findings showed that MPC has the maximum anti-corrosion efficiency across all molecules with a physical adsorption mechanism. It exhibited significant inhibition efficiency with Cu when compared with Fe and Al, based on the highest electrophilicity index (ω) values compared to other inhibitors and its impact on metals in the following manner: Cu>Fe>Al. In regards, the range of inhibitors increased by the following order: IBMP>ACG>MPC. Remarkable corrosion inhibition of MPC is demonstrated by its unique high electrophilicity, softness (σ), and lowest ∆Egap on the metal surface. These outcomes are close to the experimental

scholarly journals Anti-Corrosion Mechanism of Parsley Extract and Synergistic Iodide as Novel Corrosion Inhibitors for Carbon Steel-Q235 in Acidic Medium by Electrochemical, XPS and DFT Methods

2021 ◽  
Vol 9 ◽  
Author(s):  
Shan Wan ◽  
Huikai Chen ◽  
Tian Zhang ◽  
Bokai Liao ◽  
Xingpeng Guo
Keyword(s):  
Weight Loss ◽  
Carbon Steel ◽  
Corrosion Inhibition ◽  
Corrosion Inhibitors ◽  
Inhibition Efficiency ◽  
Physical Adsorption ◽  
Corrosion Mechanism ◽  
Dft Methods ◽  
Electrochemical Tests ◽  
Chemistry Calculation

The parsley extract (PLE) was prepared using absolute ethyl alcohol. The PLE and synergistic iodide were firstly utilized as efficacious corrosion inhibitors to slow down the corrosion rate of carbon steel-Q235 in 0.5 mol/L H2SO4 solution. The anti-corrosion performance was researched by weight loss method, electrochemical tests, surface analysis and quantum chemistry calculation. Results of electrochemical and weight loss tests show that the synergetic PLE and I− exhibit the optimal corrosion inhibition efficiency 99%. The combined inhibitor displays the favorable long-term corrosion inhibition effect, and the inhibition efficiency can maintain more than 90% after 144 h immersion. The introduction of I− makes carbon steel surface with higher negative charge amount, which could be beneficial to the interaction between corrosion inhibitor and Fe atoms. The adsorption behavior obeys the Langmuir isotherm adsorption, and involves chemical and physical adsorption. On the basis of electrochemical consequences and theoretical calculation, the adsorption process and anti-corrosion mechanisms are further explored.

scholarly journals Corrosion Inhibition and Adsorption Characteristics of Tarivid on Mild Steel in H2SO4

2010 ◽  
Vol 7 (s1) ◽  
pp. S442-S448 ◽  
Author(s):  
N. O. Eddy ◽  
E. E. Ebenso
Keyword(s):  
Mild Steel ◽  
Corrosion Inhibition ◽  
Adsorption Mechanism ◽  
Inhibition Efficiency ◽  
Physical Adsorption ◽  
Free Energy Of Adsorption ◽  
Langmuir Adsorption ◽  
Adsorption Characteristics ◽  
Kinetic And Thermodynamic Parameters ◽  
Temperature Activation

The corrosion inhibition and adsorption characteristics of (+/-)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid (Tarivid) on the corrosion of mild steel has been studied using thermometric and gasometric methods. The study reveals that tarivid inhibits the corrosion of mild steel in H2SO4. The values of inhibition efficiency of tarivid were found to increase as its concentration increased but decreased with increase in temperature. Activation energies of the inhibited corrosion of mild steel ranged from 39.05 to 50.61 kJ/mol. Values of enthalpy change and free energy of adsorption were negative which indicated exothermic and spontaneous adsorption process. Physical adsorption mechanism is proposed from the obtained kinetic and thermodynamic parameters. Langmuir adsorption isotherm model is obeyed from the fit of the experimental data.

The influence of temperature on the corrosion inhibition of API 5L X42 pipeline steel in HCl medium by gum arabic

2017 ◽  
Vol 64 (4) ◽  
pp. 409-417 ◽  
Author(s):  
Hamza Bentrah ◽  
Abdelouahad Chala ◽  
Mounir Djellab ◽  
Youssouf Rahali ◽  
Hicham Taoui
Keyword(s):  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Pipeline Steel ◽  
Physical Adsorption ◽  
Gum Arabic ◽  
Corrosion Mechanism ◽  
Content Type ◽  
Influence Of Temperature ◽  
Temperature Range ◽  
The Stability

Purpose This paper aims to investigate the influence of temperature (25-65°C) on the adsorption and the inhibition efficiency of gum arabic (GA) for the corrosion of API 5L X42 pipeline steel in 1M HCl. Design/methodology/approach Inhibition behaviour on steel in HCl has been studied in relation to the concentration of the inhibitor and the temperature using potentiodynamic polarization curves and electrochemical impedance spectroscopy. Thermodynamic parameters of adsorption were calculated from the viewpoint of adsorption theory. Findings The results show that at a temperature range from 25 to 65°C, GA was a good inhibitor for API 5L X42 pipeline steel, and its inhibition efficiency was significantly stable. The maximum inhibition efficiency (93 per cent) is obtained at 4 g L−1. In absence and presence of GA, there is almost no change in the corrosion mechanism regardless of the temperature. The adsorption of GA on steel surface is an exothermic process. The adsorption of GA involves physical adsorption. Practical implications The use of GA as an eco-friendly corrosion inhibitor is practical for carbon steel in HCl. Originality/value The stability of inhibition efficiency of GA at a temperature range from 25 to 65°C could find possible applications in acid pickling, industrial acid cleaning and acid descaling.

scholarly journals Inhibition of Corrosion of Aluminum Alloy AA8011 in Alkaline Medium Using Palisota hirsute Extract

2016 ◽  
Vol 67 ◽  
pp. 14-20 ◽  
Author(s):  
Lebe A. Nnanna ◽  
Kings O. Uchendu ◽  
Glory Ikwuagwu ◽  
Wisdom O. John ◽  
Uche Ihekoronye
Keyword(s):  
Experimental Data ◽  
Free Energy ◽  
Alkaline Medium ◽  
Steel Surface ◽  
Adsorption Mechanism ◽  
Inhibition Efficiency ◽  
Physical Adsorption ◽  
Aluminum Surface ◽  
Free Energy Of Adsorption ◽  
Gibb’S Free Energy

Gravimetric technique was used to study the inhibition of aluminium alloy AA8011 in an alkaline medium using an eco-friendly inhibitor, Palisota hirsute. The study revealed that the extract reduced the corrosion rate of aluminium AA8011 from 0.407 mm/yr to as low as 0.106 mm/yr in 0.25 M KOH after being exposed for five hours. The inhibition efficiency was found to increase as the concentration of the plant extract in the medium increased. The adsorption studies, computed from the experimental data revealed Langmuir isotherm as the best model for the isotherm (r2=0.999) on the mild steel surface. Gibb’s free energy of adsorption was also calculated and gotten to be 15.61 kJmol-1, suggesting that inhibitor molecules have been spontaneously adsorbed onto the aluminum surface through physical adsorption mechanism.

scholarly journals Characterizing Wool Keratin

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Jeanette M. Cardamone ◽  
Alberto Nuñez ◽  
Rafael A. Garcia ◽  
Mila Aldema-Ramos
Keyword(s):  
Hydrogen Peroxide ◽  
Gel Electrophoresis ◽  
Water Soluble ◽  
Alkaline Solutions ◽  
Biodegradable Material ◽  
Alkaline Hydrogen Peroxide ◽  
Cortical Cells ◽  
Sds Page ◽  
Fibrous Matrices ◽  
Wool Keratin

Keratin from wool is a reactive, biocompatible, and biodegradable material. As the biological structural component of skin (soft keratins) and of nails, claws, hair, horn, feathers, and scales (hard keratins) pure keratin comprises up to 90% by weight of wool. Wool was treated in alkaline solutions to extract from 68% to 82% keratin within 2 to 5 hours of exposure at . The keratin products were water-soluble and were confirmed to contain intermediate filament and microfibrillar component-proteins of fractured, residual cuticle, and cortical cells. Oxidation of wool by peroxycarboximidic acid in alkaline hydrogen peroxide produced keratin products with distinct microcrystalline structures: descaled fibers, fibrous matrices, and lyophilized powders. Morphology and confirmation of peptide functionality were documented by SEM, Amino Acid Analysis, SDS-PAGE gel electrophoresis, MALDI-TOF/TOF, and FTIR analyses. The reactivity of keratin from wool models the reactivity of keratin from low-value sources such as cattle hair.

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