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دراسة عليه ونظريه لفعالية بعض العقاقير كمثبطات لتاكل الالمنيوم معدن وبعض سبائكه في المحلول المحلي == Experimental and Computational Studies of Some Drugs as Corrosion Inhibitors for Aluminium and Some Its Alloys in Saline solution
Author name:
سمر ثامر حميد
Supervisor name:
شذى فاضل نارين السعيدي | تغريد علي سلمان
General topic:
Chemistry
Specific topic:
Chemistry
Degree:
Master
University:
Al-Nahrain University - College Of Science - Chemistry Department
Language:
English
University location:
Baghdad
First pages:
25T1663 - p.pdf
Abstract:
This thesis involves the investigation of the corrosion behaviour of pure aluminium as well as of two of aluminium - base alloys (5052Al and 2024Al) in sodium chloride solution over a temperature range (283 - 323 K) with and without ampicillin (AMP.), cephalexin (CEX.) and amoxicillin (AMOX.) as inhibitors.The results of electrochemical experimental study revealed that : 1. The current density increases with increasing temperature in the range of (283 - 323) K.2. The inhibition efficiency increases with increasing the concentration of inhibitors (AMP., CEX., and AMOX.), this means that these inhibitors act as an adsorption inhibitors on the surface for the corrosion of pure Al, 5052 Al, and 2024 Al in 3.5% NaCl.3. The inhibition efficiency of AMP., CEX., and AMOX. decreases with increasing temperature from 283 to 323 K. 4. According to the corrosion potential, AMP., CEX., and AMOX. act as mixed type inhibitors since corrosion potential does not change approximately in NaCl solution.5. The thermodynamic parameters of corrosion ΔH, ΔG, and ΔS have been calculated at different inhibitors concentrations and temperatures. The values of ΔG and ΔH indicate the spontaneous and exothermic corrosion processes respectivelly.6. The general behaviour for the kinetic studies depend on the Arrhenius equation. Kinetic data show that the adsorption of AMP., CEX., and AMOX. on the surface of in 3.5% NaCl is physisorption type.7. The negative values of thermodynamic functions of adsorption, ΔGads and ΔHads obtained from Langmuir isotherm, indicate the spontaneous and exothermic adsorption processes respectively.This thesis also includes theoretical calculation of ampicillin, cephalexin and amoxicillin molecules using the density functional theory (DFT) (B3LYP) with 6 - 31G basis set, which indicate that AMOX. is best inhibitor.The comparison of theoretical and experimental data exhibit good relation.The surface study by using Scanning Electron Microscopy (SEM) has been accomplished and the images show a smoother surface for pure aluminium sample in the presence (7.5×10 - 4 M) of ampicillin due to the formation of a protective barrier film through adsorption process.
