scholarly journals Corrosion inhibition of Zinc by Imidazol in Acidic Media

2009 ◽  
Vol 6 (1) ◽  
pp. 188-199
Author(s):  
Baghdad Science Journal
Keyword(s):  
Free Energy ◽  
Linear Relationship ◽  
Adsorption Mechanism ◽  
Acidic Solution ◽  
Weight Loss Measurement ◽  
Acidic Media ◽  
Protection Efficiency ◽  
Loss Measurement ◽  
Corrosion Rates ◽  
Enthalpy And Entropy

The inhibitive effect of imidazol on the dissolution of Zn in (1M) HCl has been studied. The inhibion effect of imidazol ,protection efficiency and the corrosion rate of Zn in (1M) HCl were investigated at various concentrations (1x 10-3 – 5x10-3) M and tempearture range (285-328) K. The corrosion inhibitive of Zn by imidazol was studied using weight loss measurement and analytical titration of the amounts of dissolved zinc in acidic solution in presence and absent of imidazol. It was observed that imidazol led to protection efficiency reached to (88.93)% when (10)mM imidazol concentration was used. A linear relationship came true between (C/?) and (C); where (?) is the coverage of Zn surface by imidazol which could be obtained from the rate of corrosion in the presence and absent of inhibitor in the acid solution and (C) is the concentration of imidazol. This linear relationship indicate that the inhibition action occure via Langmiur adsorption mechanism. Eventually, the corrosion rates, activated energy ,Arrhenius constant, changes in free energy, enthalpy and entropy accompanying with imidazol adsorption on Zn surface were calculated.

scholarly journals Effects of Heat Treatment on the Corrosion Behavior of ASTM A-36 Steel

2020 ◽  
Vol 10 (1) ◽  
pp. 5320-5324
Author(s):  
I. Alenezi
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Weight Loss Measurement ◽  
Acidic Media ◽  
Loss Measurement ◽  
Corrosion Rates ◽  
Heat Treated ◽  
Before And After ◽  
Quenched Steel ◽  
Steel Hardening

The effects of different tempering temperatures and heat treatment times on the corrosion resistance of rolled ASTM A-36 steel in various concentrations of hydrochloric acid (HCl) and sodium chloride (NaCl) were studied in this work, using the conventional weight loss measurement. Rolled and heat-treated specimens were placed in the acidic media for five days and for seven days in NaCl, respectively, and the corrosion rates were evaluated. The microstructure of steel before and after heat treatment was studied. Corrosion resistance revealed remarkable changes from the effect of tempering after water or oil quenching of steel. Generally, the corrosion rate increases from the effect of steel hardening. Tempering of water-quenched steel at 450Co for one hour highly improves the corrosion resistance of 0.27% carbon steel.

scholarly journals Corrosion and Kinetic Study of Eucalyptus camaldulensis Seeds Extract Percolated with Methanol on Aluminium Coupons in HCl

2020 ◽  
pp. 61-76
Author(s):  
Ishaq Yahaya Lawan ◽  
Fatima Khalil Abdullah ◽  
Sani Idris ◽  
Shinggu D. Yamta ◽  
Abdurrahman Hudu
Keyword(s):  
Weight Loss ◽  
Kinetic Study ◽  
Adsorption Mechanism ◽  
Eucalyptus Camaldulensis ◽  
Aluminum Surface ◽  
Chemical Adsorption ◽  
Weight Loss Measurement ◽  
Thermodynamic Consideration ◽  
Loss Measurement ◽  
Inhibitor Efficiency

This research discusses a detail optimization of Eucalyptus camaldulensis seeds extract as corrosion inhibitor for aluminum coupons in HCl using weight loss measurement and kinetic study. The result shows that the maximum inhibitor efficiency was obtained at a concentration of 2.0 (%W/V). However the highest inhibitor efficiency of 85% was obtained at 50ºC and the least inhibitor efficiency of 29% was obtained at 30ºC. Thermodynamic consideration revealed that adsorption of inhibitor of aluminum surface was exothermic and consistent with chemical adsorption mechanism.

scholarly journals 1-Butyl-3-Methylimidazolium Chloride Ionic Liquid as Inhibitor for Corrosion Protection of Mild Steel in Acidic Media

2019 ◽  
Vol 7 (4.14) ◽  
pp. 146
Author(s):  
A A. Ahmad Tarmizi ◽  
L Peter ◽  
D Ahtoi ◽  
R Yusof ◽  
S N.A. Syed Ismail ◽  
...  
Keyword(s):  
Weight Loss ◽  
Ionic Liquid ◽  
Mild Steel ◽  
Sulphuric Acid ◽  
Corrosion Protection ◽  
Corrosion Performance ◽  
Weight Loss Measurement ◽  
Scanning Electronic Microscopy ◽  
Acidic Media ◽  
Loss Measurement

Corrosion inhibitor is a substance added to the corrosive environment in small quantities to reduce the corrosion a metal. The addition of inhibitors will reduce the corrosion rate of the metal by retarding the corrosion process on the metal surface. Thus, this study focused on the study of the effectiveness of 1- butyl-3-methylimidazolium chloride ([EMIM]Cl) ionic liquid as an inhibitor for corrosion protection of mild steel. Two different concentrations of [EMIM]Cl (0.05 M and 0.5 M) were tested into different concentrations of sulphuric acid (0.05M, 0.10 M, 0.15 M, 0.20 M and 0.25 M). Weight loss measurement was used to determine the effectiveness of the [EMIM]Cl as inhibitor for corrosion protection. Results showed that acid concentrations play an important role for the corrosion protection process in the presence of the inhibitor. The weight loss increases as the concentration of the acid increased. The study also revealed that the concentrations of [EMIM]Cl ionic liquid effect the performance of the inhibitor. From this study, 0.5 M of [EMIM]Cl ionic liquid shows better corrosion performance compared to 0.05 M of [EMIM]Cl. At 0.25 M of sulphuric acid, the weight loss of untreated metal increased drastically from 0.0075 g at 0.5 hour to 0.0974 g at 24 hours. After treated with 0.5 M of [EMIM]Cl, the weight loss measurement slightly increased from 0.0027 g at 0.5 hour to 0.0179 g at 24 hours. This weight loss value is lower compared to mild steel treated with 0.05 M [EMIM]Cl which is 0.0469 g at 24 hours. The performance of the inhibitor in two different type of acid was also investigated. The morphology of the untreated mild steel and mild steel treated with [EMIM]Cl was investigated by scanning electronic microscopy (SEM)  

Dielectric relaxation of some aliphatic ketones in dilute solutions

1976 ◽  
Vol 54 (7) ◽  
pp. 794-799 ◽  
Author(s):  
M. P. Madan
Keyword(s):  
Free Energy ◽  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Relaxation Mechanism ◽  
Relaxation Data ◽  
Nonpolar Solvents ◽  
Aliphatic Ketones ◽  
Entropy Of Activation ◽  
Enthalpy And Entropy ◽  
Dielectric Relaxation Behavior

The dielectric relaxation behavior of 2-butanone, 2-pentanone, 2-heptanone, and 3-nonanone in dilute nonpolar solvents, n-heptane, cyclohexane, benzene, and carbon tetrachloride has been studied in the microwave region at a number of temperatures. The relaxation data have been used to estimate the free energy, enthalpy, and entropy of activation for the relaxation mechanism. The values of the relaxation time for those solutions for which there are available known data agree well with other determinations. The results have been discussed in terms of dipole reorientation by intramolecular and overall molecular rotation and compared, wherever possible, with other similar studies on aliphatic molecules.

scholarly journals Corrosion Behavior of Copper and Carbon Steel in Acidic Media

2014 ◽  
Vol 11 (4) ◽  
pp. 1577-1582
Author(s):  
Baghdad Science Journal
Keyword(s):  
Carbon Steel ◽  
Hydrochloric Acid ◽  
Sulphuric Acid ◽  
Corrosion Behavior ◽  
Effect Of Temperature ◽  
Acidic Media ◽  
Corrosion Rates ◽  
Weight Loss Method ◽  
Acid Environment ◽  
Loss Method

The corrosion behavior of copper and carbon steel in 1M concentration of hydrochloric acid (HCl) and sulphuric acid (H2SO4) has been studied. The corrosion inhibition of copper and carbon steel in 1M concentration of hydrochloric acid (HCl) and sulphuric acid (H2SO4) by Ciprofloxacin has been investigated. Specimens were exposed in the acidic media for 7 hours and corrosion rates evaluated by using the weight loss method. The effect of temperature (from 283 ºK to 333 ºK), pH (from 1to 6), inhibitor concentration (10-4 to 10-2) has been studied. It was observed that sulphuric acid environment was most corrosive to the metals because of its oxidizing nature, followed by hydrochloric acid. The rate of metal dissolution increased with increasing exposure time. Corrosion rates of carbon steel in the acidic media found to be higher.

scholarly journals Rationalisation of the activities of phenolic (vitamin E-type) antioxidants

2003 ◽  
Vol 17 (4) ◽  
pp. 753-762
Author(s):  
Christopher J. Rhodes ◽  
Thuy T. Tran ◽  
Philip Denton ◽  
Harry Morris
Keyword(s):  
Free Energy ◽  
Vitamin E ◽  
Gibbs Free Energy ◽  
State Theory ◽  
Linear Free Energy Relationship ◽  
Free Energies ◽  
Gibbs Free Energy Change ◽  
Linear Free Energy ◽  
Free Energy Of Activation ◽  
Enthalpy And Entropy

Using Transition-State Theory, experimental rate constants, determined over a range of temperatures, for reactions of vitamin E type antioxidants are analysed in terms of their enthalpies and entropies of activation. It is further shown that computational methods may be employed to calculate enthalpies and entropies, and hence Gibbs Free Energies, for the overall reactions. Within the Linear Free Energy Relationship (LFER) assumption, that the Gibbs Free Energy of activation is proportional to the overall Gibbs Free Energy change for the reaction, it is possible to rationalise, and even to predict, the relative contributions of enthalpy and entropy for reactions of interest, involving potential antioxidants.

Thermodynamics of transfer of Ph4C; scaled-particle theory and the Ph4As+/Ph4B− assumption for single ions

1979 ◽  
Vol 57 (15) ◽  
pp. 2004-2009 ◽  
Author(s):  
Michael H. Abraham ◽  
Asadollah Nasehzadeh
Keyword(s):  
Free Energy ◽  
Total Free Energy ◽  
Scaled Particle Theory ◽  
Free Energies ◽  
Particle Theory ◽  
Free Energy Of Transfer ◽  
Enthalpy And Entropy ◽  
Interaction Term ◽  
Energy Of Transfer ◽  
Entropy Of Transfer

Free energies of transfer of Ph4C from acetonitrile to 20 other solvents have been calculated from literature data. The contribution of the cavity term to the total free energy has been obtained from scaled-particle theory and Sinanoglu–Reisse–Moura Ramos theory. It is shown that there is little connection between the cavity term and the total free energy of transfer, and that there must be, in general, a large interaction term. If the latter is important for transfer of Ph4C, we argue that it must also be important for transfer of the ions Ph4As+ and Ph4B−. Previous suggestions that the interaction term is zero for transfer of these two ions are thus seen to be unreasonable. We also show, for six solvents, that the interaction term for Ph4C is very large in terms of enthalpy and entropy, and that scaled-particle theory seems not to apply to transfers of Ph4C between pure organic solvents.The free energy, enthalpy, and entropy of transfer of Ph4As+ = Ph4B− have been calculated by dividing the total transfer values into neutral and electrostatic contributions; reasonable agreement is obtained between calculated and observed values.

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