1.1 Introduction
Corrosion is defined as a destructive phenomenon, chemical or electrochemical, which can attack any metal or alloy through reaction by the surrounding environment and in extreme cases may cause structural failure. The corrosion occurs because of the natural tendency for most metals to return to their natural state; e.g., iron in the presence of moist air will revert to its natural state, iron oxide. Natural Corrosion inhibitor refers to a mixture of chemical substances or a specified chemical compound, which can exist stably at an appropriate concentration in a corrosive environment, and can play a maximum role in slowing or preventing corrosion of metal materials (Lobley et al., 2006; Muller et al., 1991). Compared with other traditional processes, the addition of corrosion inhibitors has many advantages. It can be added directly in the system without the need for other additional equipment.
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research questions, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
In recent years, the development and synthesis of new, efficient and environmentally friendly green corrosion inhibitor have attracted more and more attention. Some corrosion inhibitors represented by compounds such as nature products, ionic liquids (ILs), imidazolines, and amino acids have shown good environmental protection potential and currently received much attention corrosion inhibitors are always renewable, inexpensive, ecologically acceptable, readily available and environmentally friendly and biodegradable. It does not include other toxic compounds or heavy metals. They are appropriate for different corrosion systems (Al-Hashem, 2006; Lobley, 2006; Tems et al., 2007; Ambat et al., 2008; … Frankel et al., 2012).
Corrosion affects most of the industrial sector and may cost billions of dollars each year for prevention and replacement maintenance. Thus, the modern world has made investigations to overcome this problem by conducting enrichment studies of corrosion inhibitors. According to different corrosion conditions, selecting a suitable corrosion inhibitor has excellent corrosion inhibition effects. The amount of corrosion inhibitor is very small, and the use of a small concentration of corrosion inhibitor can play a good protective role, economically and effectively (Al-Hashem, 2006; Martin, 1999; Lobley et al., 2006; Muller et al., 1991).
Corrosion inhibitors will reduce the rate of either anodic oxidation or cathodic reduction or both. This will give us anodic, cathodic or a mixed type of inhibition. In an attempt to find corrosion inhibitors that are environmentally safe and readily available, there has been a growing trend in the use of biological substrate such as leaves or plant extracts as corrosion inhibitors for metals in acid cleaning processes.
As a result of increasing awareness on environmentally friendly practices for sustainable development, the demand for non-toxic inhibitors to replace toxic ones has increased tremendously. Thus, in recent years, several plant extracts have been investigated for the inhibition of acid corrosion of metals. This is because plants contain naturally synthesized chemical compounds that are biodegradable, environmentally acceptable, inexpensive, readily available and renewable source of materials.
Corrosion is not only dangerous, but also costly, with annual damages in the billions of dollars! If this is difficult to believe, consider some of the direct and indirect effects of corrosion which contribute to these costs: Not only that the economic costs are frightening, there is also potential loss of life and damage to the environment problems, which can have widespread effects upon modern industrial businesses. It is essential, therefore, for operators of industrial process plants to have a program for controlling corrosion.
The effects of corrosion in our daily lives can be direct by affecting the useful service lives of our possessions, and indirect, in that producers and suppliers of goods and services incur corrosion costs, which they pass on to consumers. At home, corrosion is readily recognized on automobile body panels, charcoal grills, outdoor furniture, and metal tools (Denny et al. 1996). The corrosion of steel reinforcing bars in concrete usually proceeds out of sight and suddenly results in failure of a section of bridges or buildings.
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Inhibition Efficiency of Lasienthera Africanum as a Natural Corrosion Inhibitor.
1.3 Statement of Problems
Investigation revealed that corrosion is a serious problem in this modern age of technological advancement. This accounts for a lot of economic losses and irreversible structural damage. The cost of corrosion failures annually for any nation is difficult to estimate per annum, but it has been stated that the wastage of material resources by corrosion ranks third after war and disease (Olugbenga et al., 2011).
There are numerous failures and eventual losses in the oil and gas industry have been traced to corrosion processes. Failures resulting from the inability of metals to support designed load requirement because of losses imposed by corrosion effects and this can be combated economically through the use of chemical inhibitors despite the fact that synthetic inhibitors are effective; nonetheless they are associated with problems of toxicity disposal litigation and enormous cost.
1.4 Aim and Objectives of Study
The aim of the study is to determine the Inhibition Efficiency of Lasienthera Africanum as a Natural Corrosion Inhibitor. In achieving this aim, the following specific objectives were laid out as follows:
- To evaluate the weight loss measurement, corrosion rate and inhibiting efficiency on aluminum;
- To study plant extract for natural corrosion inhibition;
- To determine the chemical composition of the metal; and
- To examine the weight loss measurement, corrosion rate and inhibiting efficiency on mild steel.
1.5 Research Questions
The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:
- Is plant extract required for natural corrosion inhibition?
- What are the weight loss measurement, corrosion rate and inhibiting efficiency on aluminum?
- What is the chemical composition of the metal?
- What are the weight loss measurement, corrosion rate and inhibiting efficiency on mild steel?
1.6 Significance of Study
This study will be of immense benefit to other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.
1.7 Scope of Study
The scope of the research is focused on the Inhibition Efficiency of Lasienthera Africanum as a Natural Corrosion Inhibitor.
1.8 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet, questionnaire and interview).
1.9 Definition of Terms
Corrosion: It is a destructive phenomenon, chemical or electrochemical, which can attack any metal or alloy through reaction by the surrounding environment and in extreme cases may cause structural failure.
