Compainly Inhibition Efficiency Of Tamarind And Moringa Leaves For Prevention Of Corrosion In Mild Steel

Description

ABSTRACT

Traditionally, reduction of corrosion has been managed by various methods including cathodic protection, process control, reduction of the metal impurity content, and application of surface treatment techniques, as well as incorporation of suitable alloys. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention in acidic media. These inhibitors slow down the corrosion rate and thus prevent monetary losses due to metallic corrosion on industrial vessels, equipment, or surfaces. Inorganic and organic inhibitors are toxic and costly and thus recent focus has been turned to develop environmentally benign methods for corrosion retardation. Many researchers have recently focused on corrosion prevention methods using green inhibitors for mild steel in acidic solutions to mimic industrial processes. The aim of this study is to investigate the corrosion inhibition of some plant extracts on mild steel in selected media. The plant extracts investigated are tamarind and moringa. The selected media are 1M HCL and H₂SO₄ and the corrosion rate on the mild steel was investigated. Results were obtained at intervals of 24, 48, 72 and 96 h, respectively. The corrosion rate and inhibition efficiency were calculated. The results revealed that moringa leaf has the best inhibition efficiency on mild steel than tamarind which also showed good inhibition efficiency.

CHAPTER ONE

• INTRODUCTION
• BACKGROUND OF THE STUDY
• AIM OF THE PROJECT
• OBJECTIVE OF THE STUDY
• SCOPE OF THE PROJECT
• TYPES OF CORROSION
• CORROSION PROTECTION OF REINFROCED CONCRETE
• IMPORTANCE OF GREEN INHIBITORS

CHAPTER TWO

2.1    LITERATURE REVIEW

2.2REVIEW OF THE LITERATURE SURVEY

2.3    REVIEW OF CORROSION PREVENTION PROCESSES

2.4    CORROSION MEDIA

2.4    EFFECT OF INCREASING INHIBITOR CONCENTRATION AND TEMPERATURE OF INHIBITION EFFICIENCY

2.5    METHODS USED FOR STUDYING INHIBITION EFFICIENCY, INHIBITOR TYPE, AND ADSORPTION PROCESS

CHAPTER THREE

3.1   METHODOLOGY

3.2    COLLECTION OF PLANT MATERIAL AND PREPARATION OF PLANT EXTRACTS

3.3    MATERIALS AND METHODS

CHAPTER FOUR

4.1    RESULTS AND DISCUSSION

CHAPTER FIVE

5.1    CONCLUSION

5.2    REFERENCES

CHAPTER ONE

1.0                                                        INTRODUCTION

The corrosion of metals is an unavoidable but controllable process. In many industries corrosion cost billions of dollars each year for prevention, replacement and maintenance most especially on mild steel.

Mild steel, also known as plain-carbon steel, is now the most common form of steel because its price is relatively low, while it provides material properties that are acceptable for many applications [1]. However, the challenge is that it has low corrosion resistance especially in acidic environments [2]. Industrial processes such as acid cleaning, pickling, descaling, and drilling operations in oil and gas exploration use acidic solutions extensively and as such iron and steel vessels or surfaces used in these environments are prone to corrosion [3]. The use of many inorganic inhibitors, particularly those containing phosphate, chromate, and other heavy metals, is now being gradually restricted or banned by various environmental regulations because of their toxicity and difficulties faced in their disposal especially in the marine industry, where aquatic life is at threat [4]. Synthetic organic inhibitors have also been extensively applied but their use is now being marred by their toxicity and high cost of manufacturing. This has prompted researchers to explore other areas to produce eco-friendly, cheap, and biodegradable green corrosion inhibitors to replace inorganic and synthetic organic inhibitors. Natural products such as plant extract, tamarind and moringa leaves have been reported to be efficient corrosion inhibitors [5]. Plant extracts are viewed as rich source of naturally synthesized chemical compounds that can be extracted by simple procedures with low cost [6]. These natural extracts are analogous to the synthetic organic inhibitors and are being proven to work as much as their synthetic counterparts. This review gives an overview of recent work on the inhibitive effect of various plant extracts particularly for mild steel in acidic medium so as to provide industrialists with vital comparative literature for possible large scale use of natural inhibitors in their operations. This will contribute to sustainable and green manufacturing. The effects of temperature, concentration, and reaction medium on the inhibition efficiency were compared. Methods used for studying corrosion and the adsorption isotherms deduced are also highlighted.

1.1                                           BACKGROUND OF THE STUDY

Mild steel, which contain small percentage of carbon and is strong and easily worked but not readily tempered or harden. Due surroundings it tend to corrode , and is affected by numbers of factors such as , metal composition, temperature, presence of gases like sulphur dioxide, hydrogen chloride, chlorine and other corrosive gases, for structure. Few studies have conducted on the consistently available corrosion inhibitor potentials of some plant extract, which may know as “green inhibitor”. In the chemical envinorment, to prevent the corrosion rate of metal by using the green corrosion inhibitor. The adsorption of inhibitor can be enhanced by the presence of hetero atoms such as N, O, P and S. Corrosion processes develop fast after disruption of the protective barrier and are accompanied by a number of reactions that change the composition and properties of both the metal surface and the local environment, for example, formation of oxides, diffusion of metal into coating matrix, local pH. Change and electrochemical potential. The study of corrosion of mild steel is a matter of tremendous theoretical and practical concern and as such as has received a considerable amount of interest. Acid solutions , widely used in industrial acid cleaning , acid descaling, acid pickling and oil well acidizing , require the use of corrosion inhibitors in order to restrain their corrosion attack on metallic materials.

1.2                                                   AIM OF THE PROJECT

The aim of this study is to investigate the corrosion inhibition of some plant extracts on mild steel in selected media. The plant extracts investigated are tamarind and moringa leaves. The selected media are 1M HCL and H2SO4 and the corrosion rate on the mild steel was investigated using mass loss method.

1.3                                               OBJECTIVE OF THE STUDY

In the view of various green corrosion inhibitions, present study is conspiring with the following objectives:

1. To determine the inhibition efficiency of tamarind and moringa leaves extract.
2. To sounding the formation of protective film on metal surface.

1.4                                                 SCOPE OF THE PROJECT

Among the several methods of corrosion control and  prevention, the use of corrosion  inhibitors is very popular. Corrosion inhibitors are substances which when added in small concentrations to corrosive media decrease or prevent the reaction of the metal with the media. Inhibitors are added to many systems, namely, cooling systems, refinery units, chemicals, oil and gas production units, boiler, and so forth.

Throughout the ages, plants have been used by human beings for their basic needs such as production of food-stuffs, shelters, clothing, fertilizers, flavors and fragrances, medicines and last but not least, as corrosion inhibitors. The use of natural products as corrosion inhibitors can be traced back to the 1930’s when plant extracts of Chelidonium majus (Celandine) and other plants were used for the first time in H₂SO₄ pickling baths (Sanyal, 1981). After then, interest in using natural products as corrosion inhibitors increased substantially and scientists around the world reported several plant extracts

In this work, extract of plants, namely, tamarind and moringa leaves are used as corrosion extract in mild steel

1.5                                                  TYPES OF CORROSION

Corrosion is defined as the deterioration of a substance or its properties due to interactions between the substance and its environment [7]. The tendency of a metal to corrode depends on the grain structure of the metal, its composition as formed during alloying, or the temperature for deformation of a single metal surface developed during fabrication. Corrosion prevention would be more practical than trying to eliminate it completely. Given that the environment plays an important part in corrosion, corrosion mechanisms can be as varied as the environments to which a substance is exposed and thus may be complex to understand. Factors that cause corrosion include reactivity of metal, presence of impurities, presence of air, moisture, gases like sulphur dioxide and carbon dioxide, and presence of electrolytes. Corrosion prevention and retardation are aimed at addressing these factors [8].

1.6                   CORROSION PROTECTION OF REINFROCED CONCRETE

The adulteration of reinforced concrete is principally due to the corrosion of the reinforcement, which occurs when the concrete has lost its ability to protect them. External pollutants found in air or water enters through the micro-pores in the concrete. In time, the chemical properties of the concrete in the vicinity of the reinforcement are altered and its ph. Drops. Once the ambient moisture penetrates through to the steel, corrosion begins. The prevention of corrosion can take numerous forms depending on the circumstances of the metal being corroded. The prevention techniques can be generally classified into following groups such as design improvement, metal selection, change of environment, electrochemical protection, coating and plating of metal and use of corrosion inhibitor.

1.7                                    IMPORTANCE OF GREEN INHIBITORS

The term corrosion is destruction of metal or alloy; they deteriorate slowly by the action of atmospheric gases, moisture and other chemicals. The rate at which it can propagate with a view of improving the lifetime of metallic and alloy materials. A corrosion inhibitor is a substance which, when added in small concentration to an environment, effectively reduce the corrosion rate of a metal exposed to that environment. To overcome those destruction of metal ,different plant extract can be used as corrosion inhibitors , which is commonly known as green corrosion inhibitors – tamarind and moringa leaves.Plants are sources of naturally occurring compounds.

Naturally occurring compounds are mostly used because they are environmentally acceptable, cost effective and have abundant availability. Some with complex molecular structures and having different chemical, biological and physical properties. By adding inhibitors in low concentrations to corrosive media is to delay the reaction between the metal and the corrosive spices in the medium.

The properties that must be met by corrosion inhibitor as:

1. Capability of reducing corrosion rate
2. The active principle of the corrosion inhibitor must be in contact with the metal.
3. Must not have side effects.