THE INHIBITORY EFFECT OF ETHANOLIC EXTRACT OF MORINGA OLEIFERA LEAF ON THE CORROSION OF MILD STEEL IN 5 M AND 1 M HYDROCHLORIC ACID (HCL)

THE INHIBITORY EFFECT OF ETHANOLIC EXTRACT OF MORINGA OLEIFERA LEAF ON THE CORROSION OF MILD STEEL IN 5 M AND 1 M HYDROCHLORIC ACID (HCl)

ABSTRACT

The extract of Moringa oleifera leaf in aqueous 5 M HCl and 1 M HCl was systematically investigated to ascertain its inhibitory effect on the corrosion of mild steel and its mechanism of inhibition by gasometric and gravimetric methods. The  inhibition  efficiency of Moringa oleifera leafon the corrosion of mild steel in the acidic media increases  simultaneously with concentration and decreases with rise in temperature. The higher activation energy observed in the presence of the extract compared to the blank is indicative of physical adsorption mechanism. The nature of adsorption of the extract on the mild steel surface was in conformity with Langmuir isotherm.   

CHAPTER ONE – INTRODUCTION

1.1 Background of study

Corrosion of materials has continued to receive interest in the technological world as its effects on the structural integrity of materials has been a question for some time. Metallic materials are still the most widely used group of materials particularly in mechanical engineering and the transportation industry. In addition, metals are commonly used in electronics and increasingly also in the construction industry (Buchweishaija, 2009a).

However, the usefulness of metals and alloys is constrained by one common problem known as corrosion. Hence, it has been studied comprehensively since the industrial revolution in the late eighteenth century (Sato, 2012). Corrosion is a naturally occurring phenomenon defined as deterioration of metal surfaces caused by the reaction with the surrounding environmental conditions (Buchweishaija, 2009a). Corrosion can cause disastrous damage to metal and alloy structures causing economic consequences in terms of repair, replacement, product losses, safety and environmental pollution. Due to these harmful effects, corrosion is an undesirable phenomenon that ought to be prevented.

THE INHIBITORY EFFECT OF ETHANOLIC EXTRACT OF MORINGA OLEIFERA LEAF ON THE CORROSION OF MILD STEEL IN 5 M AND 1 M HYDROCHLORIC ACID (HCl)