effect of inhibitor(neem leaf) on corrosion of galvanized steel and roofing nail in saline environment (nacl)

Description

ABSTRACT

Inhibitory effect of the neem extract (Azadirachta indica) for galvanized steel and roofing nail in NaCl solution was studied. The studies revealed that the corrosion inhibition efficiency rises with extract concentration. Inhibition efficiency increases up to 600 ppm then it stabilizes. Inhibition efficiency was found to be 86% at 600 ppm and increases with elevation in temperature. The decrease in activation energy (Ea) and enthalpy shows that corrosion inhibition is chemisorption and exothermic in nature respectively. Electrochemical experiments were performed with and without inhibitor and results were discussed. Result showed that neem leaf extract (Azadirachta indica) is a promising candidate to minimize the corrosion in alkaline medium, as it shows good inhibition efficiency.

 TABLE OF CONTENTS

 TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

• INTRODUCTION
• background of the study
• problem statement
• aim and objective of the project
• Significance of the study
• Scope of the study

CHAPTER TWO

2.0      LITERATURE REVIEW
2.1      Review of the study
2.3     Neem plant – Azadirachta indica (AZI)

2.3     Neem Plant description

2.4    Ecology of neem

2.5    Uses of neem

2.6      Galvanized steel

2.7      Advantages of galvanized steel

CHAPTER THREE

3.0      MATERIAL AND METHOD

3.1      Preparation of specimen

3.2     Plant extract preparation
3.3       Gravimetric study
3.4       Potentiodynamic polarization measurements

 

CHAPTER FOUR

RESULT ANALYSIS

4.0   Result and Discussion

CHAPTER FIVE

• Conclusions

References

 

CHAPTER ONE

INTRODUCTION

1.1                                        Background of the study

Corrosion is a natural phenomenon and is defined as detoriation of metal due to adverse environmental condition. Corrosion is a very damaging process, as it affects the act of metallic material which used in industries(Sharma et al, 2009).

The corrosion of metals in many industries, constructions, installations, and civil services such as electricity, water, and sewage supplies is a serious problem.

Consequences of corrosion are losses in the properties of metal like ductility, malleability and weakening of metal. It has been evidenced that, in alkaline medium, the layer forming on metal acts as a double layer model. In alkaline solution, formation of strong passivation appears on surface of metal. However, in the presence of CL- ions, the passivation is weakened, which leads to corrosion at higher rate(Sharma et al, 2009).

In order to prevent or minimize corrosion, inhibitors are usually used especially in flow cooling systems. Organic, inorganic, or a mixture of both inhibitors can inhibit corrosion by either chemisorption on the metal surface or reacting with metal ions and forming a barrier-type precipitate on its surface

Galvanized steel metal is commonly used in various industries while roofing nails are mostly used in building industries. However, these metals are exposed to aggressive environment namely alkaline, acidic medium and salt solution through many engineering developments (Sharma et al, 2009).

Though different methods to protect metal from aggressive environment, namely corrosion preventing coating, cathodic and anodic prevention technique are available, green corrosion inhibitors is inexpensive and environmentally friendly.

When metal gets exposed to the aggressive environment, the extent of corrosion depends on operating condition (T,pH), time of exposure of metal in that environment, with and without inhibitor, and type of aggressive environment5.

Green corrosion inhibitors are derived from plants and used in small quantity to combat the corrosion6. Inhibitors should have the ability to reduce the corrosion rate and metal protected from corrosive environment. Small quantities of inhibitor should result in higher corrosion inhibition efficiency. Neem leaf extract was proposed green corrosion inhibitor for corrosion inhibition of galvanised steel in saline environment (NACL) due to its antioxidant property

In this work, the chemical behaviour of galvanized steel and roofing nail with 0.5 wt% NaCl solution at different temperatures and concentration with and without inhibitor (neem leaf extract) is reported with the data obtained from gravimetric method, potentiodynamic polarization technique.

1.2       Problem statement

According to Bothi et al (2018), the used of organic compounds to determine the corrosion inhibition potential are not only expensive, but also toxic to living beings. It is the important to look for cheap and safe inhibitors of corrosion.

Plant extracts was chosen to solve the above mentioned problem this is because they are environmentally acceptable, readily available, and renewable source for wide range of inhibitors (Rajendran et al, 2014). They are the rich sources of ingredients which have very high inhibition efficiency and are hence termed “Green Inhibitors” (Lebrini et al, 2018). Green corrosion inhibitors are biodegradable and do not contain heavy metals or other toxic compounds (Sharma et al, 2009).This study was carried out to show the significant inhibition efficiency of neem leaf.

1.3                                        Aim and objectives of the study

The main aim of this study is to determine the Inhibitory effect of the neem extract (Azadirachta indica) for galvanized steel and roofing nail in 1 wt% Ca(OH)2 + 0.5 wt% NaCl solution. The objectives are:

1. To determine the corrosion inhibiting strength of neem leaf on galvanised steel and roofing nail.
2. To determine the chemical behaviour of galvanized steel with 1 wt% Ca(OH)2 + 0.5 wt% NaCl solution at different temperatures and concentration with and without inhibitor (neem leaf extract).

• To determine the inhibition efficiency of neem leaf

1.4                                        Significance of the study

Using neem leaf which is one of the plant extracts and organic species is very important way of protecting corrosion because it is environmentally acceptable, readily available, and renewable source for wide range of inhibitors.

The result of this study would help reduce the economic cost of corrosion control as well as decrease the subsequent environmental threats from inhibitor usage because neem leaves extract is non-toxic and biodegradable.

1.4                                        Scope of the study

The scope of this study covers the inhibition efficiency of corrosion of the extract of neem leaves (Azadirachta indica) on galvanised steel and roofing nail with a sodium chloride. Corrosion speed was determined and it was found that the Neem extract, at a lower concentration, reached better efficiencies on galvanised steel and roofing nail in sodium chloride Besides, through the adjustment to the Langmuir’s isotherms, it was possible to determine that the nem extract was adsorbed spontaneously on the surface of carbon steel and allowed to delay the corrosive process when reaching inhibition efficiencies of 90%. Results of this research allow establishing that the neem extract has a high potential as corrosion inhibitor to be applied in the industry as corrosion preventive medium.