Investigation of corrosion inhibition potential of selected biological inhibitors

Abstract

In this paper, corrosion inhibition potential of two biological compounds namely azadirachta indica and enzyme on corrosion of mild steel was investigated. The weight loss analysis method was used to assess the corrosion losses in mild steel exposed to saline solutions with or without inhibitors over a period of 576 days and the corrosion rates, inhibitors’ efficiencies and surface coverage were determined. The results showed that the rate of corrosion of mild steel generally does not change significantly after 400 days of continuous exposure to the same solution. Addition of enzyme to low and high saline solutions significantly reduced the corrosion rate of mild steel relative to the use of saline solutions alone. High corrosion inhibition efficiency was observed with the application of enzyme and its efficient concentration was found to be 2 wt.% in both low and high saline solutions. The corrosion inhibition of azadirachta indica was however found to be more efficient in low saline solution and an optimum concentration of 2 wt.% was efficient in this environment but in high saline solution, higher concentration of 10 wt.% is required for efficient corrosion inhibition.