CHAPTER ONE

INTRODUCTION

1.1 Background to the Study

Corrosion remains one of the most significant problems affecting metals and alloys across industries. Mild steel is widely used because it is affordable, easy to shape and strong enough for many engineering applications. However, it corrodes easily when exposed to harsh environments. Industries that use mild steel often experience equipment failure, economic losses and safety risks because of corrosion. Researchers observe that corrosion in acidic environments is particularly aggressive because acids increase the rate of metal deterioration (Author, Year). As a result, industries that use acid solutions for cleaning, pickling or processing face higher risks.

Corrosion affects pipelines, storage tanks, boilers, construction materials and household tools. The continuous damage reduces the lifespan of equipment and increases maintenance costs. Many industries rely on corrosion inhibitors to protect metals. These inhibitors slow the reaction between the metal surface and corrosive agents. Conventional inhibitors are effective, but they often contain synthetic chemical compounds. These compounds can be toxic, expensive and harmful to the environment. Therefore, the search for safe, natural and inexpensive alternatives continues to grow.

Plant extracts now attract attention as possible corrosion inhibitors. Many extracts contain organic compounds such as tannins, alkaloids, flavonoids and phenols. These compounds adsorb onto metal surfaces and form protective layers that reduce corrosion. Researchers describe plant based inhibitors as biodegradable, non toxic and eco friendly (Author, Year). They are also more affordable because they come from natural sources that are available in many regions.

Nigeria has rich biodiversity. Many local plants contain chemical structures that could inhibit corrosion. However, only a few plant species have been tested scientifically. Therefore, more studies are needed to identify effective plant extracts and evaluate their performance in acidic solutions. The use of plant extracts can support environmental sustainability and reduce the cost of metal protection.

This study examines the effects of selected plant extracts on mild steel corrosion in an acidic medium. It evaluates the inhibition efficiency and investigates how concentration influences performance.

1.2 Statement of the Problem

Corrosion continues to damage mild steel equipment used in industries such as construction, petroleum, power generation and manufacturing. Many industrial processes require acidic solutions. These acids react aggressively with metal surfaces and increase corrosion rates. Frequent equipment failure disrupts operations and creates additional repair costs. Some failures also pose safety risks to workers.

Although synthetic corrosion inhibitors are widely used, they present major challenges. Many synthetic compounds are toxic, expensive and difficult to dispose safely. They contaminate soil and water when released into the environment. Due to increased environmental regulations, industries now seek safer alternatives. Plant extracts offer a promising option, but only a limited number have been tested in controlled laboratory conditions. Many potential plants remain unexplored despite their availability and low cost.

The main challenge is that the corrosion inhibition potential of many local plants remains unknown. In addition, there is limited information on how extract concentration affects inhibition efficiency. Because of this gap, industries cannot adopt plant based inhibitors confidently. This study addresses these challenges by evaluating the effectiveness of selected plant extracts on mild steel in an acidic environment.

1.3 Aim of the Study

The aim of this study is to assess the effectiveness of plant extracts as corrosion inhibitors for mild steel in acidic environments.

1.4 Objectives of the Study

The specific objectives are:

1. To prepare extracts from selected plants and analyze their chemical properties.

2. To expose mild steel specimens to acidic solutions containing different concentrations of extracts.

3. To measure corrosion rates and determine inhibition efficiency.

4. To compare the performance of the extracts and identify the most effective one.

5. To evaluate how extract concentration influences corrosion inhibition.

1.5 Research Questions

The study seeks to answer the following questions:

1. Which plant extracts show significant corrosion inhibition on mild steel in acidic media

2. How does extract concentration influence the inhibition efficiency

3. What are the corrosion rates of mild steel with and without plant extracts

4. Which extract provides the highest level of protection

1.6 Research Hypotheses

The following hypotheses will be tested:

H1: Plant extracts significantly reduce the corrosion rate of mild steel in acidic environments.
H0: Plant extracts do not significantly reduce the corrosion rate of mild steel in acidic environments.

1.7 Significance of the Study

This study is important for several reasons. First, it explores natural alternatives to synthetic corrosion inhibitors. Plant extracts are safe and biodegradable. They do not pose environmental hazards. This makes them suitable for industries seeking eco friendly solutions. Second, the study supports the development of low cost inhibitors. Many industries in developing countries need affordable corrosion prevention methods. Plant based inhibitors can reduce costs because they come from local and abundant materials.

Third, the study contributes to scientific knowledge. It provides data on the inhibition efficiency of specific plant extracts. Researchers and students can use the results to improve future studies. Industries can also use the findings to design corrosion control strategies that match their operating conditions. In addition, the study encourages sustainable engineering practices. Using plant resources aligns with global efforts to reduce chemical pollution and promote renewable solutions.

1.8 Scope of the Study

This study focuses on assessing corrosion inhibition on mild steel using selected plant extracts. It is limited to acidic environments and does not include alkaline or neutral conditions. The study covers extract preparation, weight loss experiments and efficiency analysis. It does not assess temperature effects, electrochemical testing or long term industrial application. The plant extracts tested are limited to those available for the study period.

1.9 Limitations of the Study

The study may face several limitations. The composition of plant extracts can vary depending on soil conditions, plant maturity and extraction methods. These variations may influence inhibition efficiency. Laboratory equipment availability may also limit the range of tests conducted. Another limitation is that laboratory conditions do not always represent real industrial environments. Despite these limitations, the study uses standard procedures to ensure reliable and valid results.

1.10 Organization of the Study

The research is arranged into five chapters. The first chapter introduces the study and outlines its key components. The second chapter provides a review of existing literature on corrosion, plant based inhibitors and acidic environments. Research methods and experimental procedures appear in the third chapter. The fourth chapter contains the results and offers a detailed discussion of their implications. Finally, the fifth chapter presents the conclusion and gives recommendations for further research.