Browsing by Author "Offurum, Julius Chigozie"

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    Comparative analysis of corrosion inhibition effects of esters of castor seed and rubber seed oils in flow pipes
    (Federal University of Technology, Owerri, 2021-02) Offurum, Julius Chigozie
    Research work on “Comparative analysis of corrosion inhibition effects of ester of castor seed oil (ECSO) and Ester of Rubber Seed Oil (ERSO) in mild steel flow pipes” was carried out. The oil samples were extracted using solvent extraction techniques (n-hexane for castor seed oil and petroleum ether for rubber seed oil). The castor and rubber seeds were ground, and respectively soaked in the n-hexane and petroleum ether before subsequent subjection to soxhlet extraction, to obtain purer oils. The oils were esterified to obtain ECSO and ERSO. Phytochemical analysis of the esterified oils was conducted to reveal the presence of alkaloid, flavonoid, tannins, cardiac glycocide, phenol, phytate, saponin and oxalate that are responsible for protection of the mild steel specimen. The mild steel samples were immersed in a flowing sulphuric acid solution held at various temperatures and pressures. Potentiodynamic polarization was used to determine the influence of the inhibitors on corrosion potential. Scanning electron microscopy provided surface-distorted information about the interaction between the acid medium/inhibitors and the mild steel, while Fourier transform infrared spectroscopy revealed the functional groups present in the inhibitors. The phytochemical evaluation results obtained showed that ECSO has alkaloid value of 2.2%, flavonoid (1.2%), tannic acid (8.6%), cardiac glycocide (7.0%), phenol (0.912mg/100g), Phytate (11.3%), Saponin (1.4%) and Oxalate (12937.5mg/100g), while those of ERSO have values of 2.1%, 43.5%, 12.0%, 28.0%, 1.605mg/100g, 10.8%, 11%, 59062.5mg/100g respectively. Inhibition efficiencies of ERSOtreated dynamic runs at 10g/l, 15g/l, 20g/l concentrations and at all treatment temperatures were higher than those of ECSO; maximum inhibition efficiencies for ERSO and ECSO applications were respectively 64.4% and 34.4% at 50% stroke, 20g/l dosage and 40oC. Furthermore, increase in treatment temperatures and pressures drastically lowered the 22 inhibition efficiency; the results obtained fit the Langmuir model for both inhibitors, with R2 values tending towards unity. Inhibition efficiencies of ERSO-reacted static runs, obtained from potentiodynamic polarization measurements were also higher than those of ECSO, peaking at 81.70% whereas that of ECSO peaked at 75.40%, both for 20g/l treatments at ambient temperature. Scanning electron microscope, SEM pictures of the mildsteel immersed in ECSO and ERSO showed the existence of absorbate species, while Fourier transform infrared spectroscopy, FTIR spectra revealed that there were shifts due to O-H/N-H and C=O stretching frequencies from 3386cm-1 to 3209cm-1 and from 1743cm-1 to 1203cm-1 respectively. The inhibitor samples were able to inhibit mildsteel corrosion substantively, but ERSO gave better corrosion inhibition effects than ECSO.