Browsing by Author "Ufondu, Pearl Chienye"

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    Corrosion inhibition of mild steel using extracts of velvet bean (Mucuna pruriens) and kava leaves (Piper methysticum)
    (Federal University of Technology, Owerri, 2018-10) Ufondu, Pearl Chienye
    This work investigated two plant leaves extract Velvet Bean and Kava, for inhibition properties and measured their efficiencies with change in time, extract concentration, and media. The metal used was mild steel, and the media HCl and NaCl. It also determined their optimum extract concentration among the tested range. Statistical analysis were also carried out on experimental results. Velvet bean leaf extract was obtained using ethanol in a hot extraction process through reflux. Kava leaf was juiced fresh because of its high moisture content. Extract concentrations - 1000, 2000, 3000, 4000, and 5000mg/L were prepared for both leaves. The different concentrations for both leaves were tested in 1M HCl medium first, for five days respectively. The different concentrations for Velvet bean leaf were also used in NaCl medium for twenty-five days. In both HCl and NaCl media, the optimum concentration for Velvet bean leaf extract was 4000mg/L, after five days (91.77% efficiency) and twenty-five days (65.44% efficiency) respectively. For Kava leaf, the optimum extract concentration in 1M HCl media was 5000mg/L also after five days (94.16% efficiency). The efficiencies of both inhibitors were seen to increase as their concentrations were increased, and reduce as time increased. Velvet bean leaf extract was also seen to be fairly stable in both acid and base media over time. In NaCl solution, its efficiency was 65.44% after twenty-five days immersion, and 93.14%, after a delayed immersion of two weeks in 1M HCl solution. Statistical analysis showed VBL extract obeyed a quadratic model in both media, and KVL a pure quadratic model. Their high R2 values close to unity showed the adequacy of the models respectively and validated the experimental data. Extract concentration and time had a high effect on inhibition efficiency and were statistically significant. It would be of an advantage to quickly apply the use of these two plant leaves extracts in inhibiting corrosion on mild steel in 1M HCl and NaCl media, in actual industrial environments. Research should be done to check the extracts behaviour and corrosion inhibition efficiency at elevated temperatures, and other media. Even though these two plants could grow all year round, and are not yet popular as food in Nigeria, it would be beneficial for more research to be done on synthesising inhibitor components of the plants in the laboratory so as not shorten food supply by other plant use.