Aluminium, being a highly reactive metal, corrodes rapidly in acidic (pH < 6) and alkaline (pH > 12.5) media. Hence it has to be protected when it is likely to come in contact with such solutions, e.g., during cleaning or acid pickling. One method of protection is the addition of inhibitor to the corroding medium. In the present work, ethanol extract of Azadirechta indica and Murraya koenigii leaves have been investigated as corrosion inhibitor for aluminium in aqueous hydrochloric acid.
The corrosion of Alluminium in plain hydrochloric acid, as well as inhibited, is found to increase with a rise in temperature. Thus in uninhibited 0.5 M HCl the loss in weight due to corrosion for an exposure period of 60 min increases from 736 mg/dm2 at 35oC to 852, 922, and 958 mg/dm2 at 45oC, 55oC and 65oC respectively.
In inhibited 0.5 M HCl containing 1.30% of Azadirechta indica, it was observed that at 35oC and for an exposure period of 60 min Azadirechta indica confer 100.0% protection. In A. indica, it is observed that the compound at 1.30% concentration show an efficiency 100.0% at 35°C. As the temperature is increased the efficiency decreases. In the case of A.indica, the efficiency decreases slightly and is found to be 72.96% at 65°C. It appears that in the case of Azadirechta indica, the adsorption is of physisorption type which decreases with a rise in temperature.
The surface morphology of the Al samples in the absence and presence of A.indica and M.koenigii leaves extract was investigated after weight loss using SEM technique. The badly damaged surface obtained when the metal was kept immersed in 0. 5 M HCl for 60 min without inhibitor indicates significant corrosion. However, in presence of inhibitor the surface has remarkably Improve with respect to its smoothness indicating considerable reduction of corrosion rate. This improvement in surface morphology is due to the formation of a good protective film of inhibitor on aluminium surface which is responsible for inhibition of corrosion. The order of efficiency at 1.30% v/v inhibitor concentration in 0.5 M hydrochloric acid was found to be : Azadirechta indica (100.0%) Murraya koenigii ( 94.79%)
Table of Contents
Chapter -1. Introduction of corrosion
1.1 General Aspect of Corrosion
1.2 Factors Influencing Corrosion
1.3 Types of Corrosion
1.4 Aim of Research work
1.5 References
Chapter -2. Performance and Impact of plant extracts as Metallic Corrosion Inhibitors
2.1 Plant extract as Corrosion Inhibitors
2.2 Effect of Functional Group on Inhibitors
2.3 Classification of Inhibitors
2.4 Phenomenon of Adsorption
2.5Azadirechtaindica utilized in the present work its properties
And uses as corrosion inhibitor
2.6Murrayakoenigii utilized in the present work its properties
And uses as corrosion inhibitor
2.7References
Chapter -3.Spectral studies on plants use as green inhibitor
3.1 Infrared spectroscopy
3.2 X-ray fiuoresence study
3.3 References
Chapter -4. Experimental Methods and Discussion of the Results
4.1 Experimental Method
4.2 Preparation of plant extract
4.3 Discussion of the Results
4.4 Effect of Inhibitor Concentration
4.5 Effect of Exposure Period
4.6 Effect of Temperature
4.7 Scanning electron microscopic study
4.8 References
Chapter -5. Summary of the Dissertation
5.1 Effect of Inhibitor Concentration
5.2 Effect of Exposure Period
5.3 Effect of Temperature
5.4 Scanning electron microscopic study
Research Objectives and Themes
This research aims to investigate the corrosion inhibition properties of ethanol extracts from Azadirachta indica and Murraya koenigii leaves for aluminium in an aqueous hydrochloric acid environment. The study seeks to evaluate the effectiveness of these natural, eco-friendly plant extracts as cost-effective alternatives to synthetic inhibitors, focusing on optimizing inhibitor concentrations and understanding the underlying adsorption mechanisms.
- Corrosion inhibition efficiency of plant-based natural extracts.
- Evaluation of weight loss and surface morphology changes.
- Influence of concentration, exposure period, and temperature on corrosion rates.
- Adsorption isotherms and spectral analysis for mechanistic insights.
Excerpt from the Book
1.1 General Aspects of Corrosion
In recent years corrosion by chemical and electrochemical reactions has assumed great economic importance throughout the world. The estimated annual loss due to corrosion is enormously large. Studies worldwide have shown that the overall cost of corrosion amount to at least 2-3% of the Gross National Product and that 20-25% of the cost could be avoided by using appropriate corrosion control technology [1]. The corrosion of a metal or a material is a global scientific problem as it affects different walks of life especially in metallurgical, chemical, materials and oil industries. Corrosion is defined as the degradation of materials or its properties due to a reaction with the environment. Corrosion exists in virtually all materials, but is most often associated with metals. Metallic corrosion is a naturally occurring process whereby the surface of a metallic structure is oxidized or reduced to a corrosion product such as “rust” by chemical and electrochemical reaction with the environment. The surface of metallic structures is attacked through the migration of ions away from the surface, resulting in material loss over time. The process of corrosion requires the presence of an anode, a cathode, an electrolyte and electrical circuit [2].
The problem of preventing the metallic corrosion is extremely complex but it is of great technological and economical importance. Corrosion of metals can be controlled by taking suitable preventive measures such as painting, plating, use of expensive alloys, use of inhibitors, etc. It is justifiable that several corers of rupees are spent on research for controlling corrosion [3].
Chapter Summaries
Chapter -1. Introduction of corrosion: Provides an overview of metallic corrosion, including its economic impact, influencing factors, and different types of corrosion.
Chapter -2. Performance and Impact of plant extracts as Metallic Corrosion Inhibitors: Examines the role of plant extracts as inhibitors, their classification, and the phenomenon of adsorption on metallic surfaces.
Chapter -3. Spectral studies on plants use as green inhibitor: Details the spectral analysis of Azadirachta indica and Murraya koenigii leaves using Infrared and X-ray fluorescence studies.
Chapter -4. Experimental Methods and Discussion of the Results: Describes the experimental methodology including weight loss measurements and discusses the results regarding inhibitor concentration, exposure period, and temperature.
Chapter -5. Summary of the Dissertation: Recaps the research findings and summarizes the effects of different experimental parameters on the corrosion inhibition efficiency.
Keywords
Aluminium, Hydrochloric acid, Corrosion inhibition, Azadirachta indica, Murraya koenigii, Weight loss method, Adsorption, Green inhibitors, SEM analysis, Surface morphology, Acid concentration, Temperature effect, Exposure period, Ethanol extract, Metallic corrosion.
Frequently Asked Questions
What is the core focus of this research?
The research focuses on utilizing natural plant extracts, specifically Azadirachta indica and Murraya koenigii, as eco-friendly corrosion inhibitors for aluminium in a hydrochloric acid medium.
What are the primary thematic fields covered?
The work covers electrochemical corrosion, plant-based inhibitor performance, surface analysis techniques like SEM, and the thermodynamic study of adsorption processes.
What is the primary goal of the study?
The primary goal is to find efficient, low-cost, and environmentally safe inhibitors to protect aluminium against aggressive acidic corrosion.
Which scientific methods are employed?
The study utilizes weight loss measurements, spectral analysis (Infrared and X-ray fluorescence), and Scanning Electron Microscopy (SEM) to assess corrosion inhibition performance.
What topics are discussed in the main body?
The main body details the experimental methodology, the impact of various inhibitors, their concentrations, and environmental factors like temperature and exposure time on corrosion rates.
Which keywords best characterize this work?
The research is best characterized by keywords such as corrosion inhibition, aluminium, green inhibitors, Azadirachta indica, Murraya koenigii, adsorption isotherms, and SEM analysis.
How does the temperature affect the corrosion inhibition efficiency?
The study indicates that inhibitor efficiency generally decreases with a rise in temperature, although the extent of this reduction varies depending on the specific inhibitor and its concentration.
What role does the concentration of plant extract play in the inhibition process?
At low concentrations, plant extracts may accelerate corrosion, but higher concentrations significantly improve inhibition by forming a protective film on the metal surface.
- Arbeit zitieren
- Dr. Vijay Ram et al. (Autor:in), Meera (Autor:in), Pravin N. Ram (Autor:in), Dr. Taslim Ahemad T. Khatri (Autor:in), Dr. Pragnesh N. Dave (Autor:in), 2014, Corrosion Inhibition of Aluminium in Hydrochloric Acid by Natural Plant Extracts, München, GRIN Verlag, https://www.grin.com/document/279280
