Alkaloid and Non Alkaloid Extracts of Solanum melongena Leaves as Green Corrosion Inhibitors on Carbon Steel in Alkaline Medium

The corrosion and inhibition behavior of Carbon steel (CS) in high alkaline solution [Sodium trioxocarbonate (IV)] in the presence of alkaloid and non alkaloid extracts of Solanum melongena leaves have been studied using conventional methods - mass loss and gasometric techniques. The results indicate that the extracts inhibit the corrosion of Carbon steel. However, the Alkaloid extract of Solanum melongena leaves (AESML) exhibits higher maximum inhibition efficiency of 81.1% than Non alkaloid extract of Solanum melongena leaves [NAESML] (65.1%) at 3.0 g/L concentration. Inhibition efficiency increase with increasing concentration of extracts but decreased with rise in temperature. Inhibition mechanism was deduced from the activation and thermodynamic parameters that govern the process. Adsorption of extract on the CS was found to obey the Langmuir adsorption isotherm. The phenomenon of physical adsorption is proposed from the obtained thermodynamic parameters. Keywords: Mass loss, thermodynamics, inhibition efficiency, half life, gasometric analysis, adsorption

Inhibition and Adsorption impact of Leave Extracts of Cnidoscolus Aconitifolius on Corrosion of Aluminium Sheet in 1 M Hcl Medium

Corrosion inhibition in the presence of alokaloid and non alkaloid extracts of Cnidoscolus aconitifolius in 1M HCl was studied using the weight loss and hydrogen evolution techniques at 303, 313 and 333 K. The results obtained revealed that the inhibition efficiency decreased with increase in temperature. Inhibition occurred through adsorption of the alokaloid and non alkaloid extracts molecules on the metal surface. The apparent activation energies, enthalpies and entropies of the dissolution process and the free energies and enthalpies for the adsorption process were determined and discussed. The fundamental thermodynamic functions were used to evaluate important inhibitive properties of Cnidoscolus aconitifolius.Keywords: Activation energy; Gibb’s Free Energy; Langmuir adsorption; Cnidoscolus aconitifolius; Aluminium sheet

Sulphuric Acid Corrosion of Mild Steel in Leave Extracts of Cnidoscolus aconitifolius Plant

Alkaloid and nonalkaloids extracts of Cnidoscolus aconitifolius leaves is reported as corrosion inhibitor of mild steel in HCl. Conventional weight loss measurements and Tafel polarization techniques are employed to study the effect on mild steel corrosion in H2SO4 solutions. The weight loss result revealed that both plant extracts are excellent corrosion inhibitors. Electrochemical polarization data revealed that mixed mode of inhibition. The increase in %IE with change in concentration of the extracts suggests the strong adsorption of active molecules leading to the formation of a protective layer on the mild steel surface.  It was found that adsorption of both leaf extracts followed Langmuir adsorption isotherm model. Keywords: Weight loss, Langmuir isotherm, activation energy, corrosion current density, inhibition efficiency, Cnidoscolus aconitifolius

Green Corrosion Inhibitors for Mild Steel in H2SO4 Solution: Flavonoids of Gongronema latifolium

The inhibitive properties of flavonoids extracted from Gongronema latifolium (FEGL) and the crude extracts from Gongronema latifolium (EEGL) on the corrosion of mild steel in H2SO4solutions was studied using hydrogen evolution method at 30, 40, 50, and 60oC. The results revealed that the extracts act as good inhibitors for the corrosion of mild steel in 5.0 M H2SO4 solutions. The inhibition efficiencies were found to increase with increase in the extract concentration and decreased with increase in temperature. The order of efficiency was EEGL > FEGL. The experimental data fitted well into the Langmuir adsorption isotherm. Physical adsorption mechanism was proposed for the adsorption of the extracts on the mild steel surface from the data obtained for the activation energies of the inhibited and uninhibited systems. Keywords: Adsorption; Corrosion; Flavonoids; Inhibitor; Mild Stee

Corrosion Inhibition Effects and Adsorption Characteristics of Ethanol Extract of King Bitters Root (Andrographis paniculata) on Mild Steel in Hydrochloric and Tetraoxosulphate (VI) Acid Media

The corrosion inhibition performance of ethanol extract of Andrographis paniculata (King Bitter) root (EEAPR) on the corrosion of Mild Steel (MS) in 1.0 M HCl and H2SO4 acid solutions at 303K and elevated temperatures of 313, 323 and 333K was investigated and compared. The experimental work was performed by the use of weight loss and hydrogen evolution techniques. The results indicate that the extract inhibit the corrosion of mild steel in both acid media. However, the EEAPR exhibits higher maximum inhibition efficiency of 98.9 % in HCl than in H2SO4 (95.0 %) at 5.0 g/L. Inhibition efficiency was found to increase with increasing concentration of extract in both acid media but decreased with rise in temperature. Inhibition mechanism was deduced from the temperature dependence of the inhibition efficiency as well as from activation parameters that govern the process. Adsorption of extract on the MS sample in both acid media was found to obey the Langmuir adsorption isotherm. The phenomenon of physical adsorption is proposed from the obtained thermodynamic parameters. </jats:p

Alkaloid and Non Alkaloid Extracts of Solanum melongena Leaves as Green Corrosion Inhibitors on Carbon Steel in Alkaline Medium

The corrosion and inhibition behavior of Carbon steel (CS) in high alkaline solution [Sodium trioxocarbonate (IV)] in the presence of alkaloid and non alkaloid extracts of Solanum melongena leaves have been studied using conventional methods - mass loss and gasometric techniques. The results indicate that the extracts inhibit the corrosion of Carbon steel. However, the Alkaloid extract of Solanum melongena leaves (AESML) exhibits higher maximum inhibition efficiency of 81.1% than Non alkaloid extract of Solanum melongena leaves [NAESML] (65.1%) at 3.0 g/L concentration. Inhibition efficiency increase with increasing concentration of extracts but decreased with rise in temperature. Inhibition mechanism was deduced from the activation and thermodynamic parameters that govern the process. Adsorption of extract on the CS was found to obey the Langmuir adsorption isotherm. The phenomenon of physical adsorption is proposed from the obtained thermodynamic parameters.</jats:p

Corrosion Inhibition Effects and Adsorption Characteristics of Ethanol Extract of King Bitters Root (Andrographis paniculata) on Mild Steel in Hydrochloric and Tetraoxosulphate (VI) Acid Media

The corrosion inhibition performance of ethanol extract of Andrographis paniculata (King Bitter) root (EEAPR) on the corrosion of Mild Steel (MS) in 1.0 M HCl and H2SO4 acid solutions at 303K and elevated temperatures of 313, 323 and 333K was investigated and compared. The experimental work was performed by the use of weight loss and hydrogen evolution techniques. The results indicate that the extract inhibit the corrosion of mild steel in both acid media. However, the EEAPR exhibits higher maximum inhibition efficiency of 98.9 % in HCl than in H2SO4 (95.0 %) at 5.0 g/L. Inhibition efficiency was found to increase with increasing concentration of extract in both acid media but decreased with rise in temperature. Inhibition mechanism was deduced from the temperature dependence of the inhibition efficiency as well as from activation parameters that govern the process. Adsorption of extract on the MS sample in both acid media was found to obey the Langmuir adsorption isotherm. The phenomenon of physical adsorption is proposed from the obtained thermodynamic parameters. Keywords: Weight loss, Thermodynamics, Inhibition efficiency, Surface coverage, Hydrogen evolution

ALUMINIUM CORROSION ABATEMENT USING NON TOXIC AND ECO-FRIENDLY ORGANIC INHIBITORS

The corrosion inhibition performance of the alkaloid and non alkaloidleaf extracts of Cnidoscolus aconitifolius (AECAL and NAECAL) on the corrosion of aluminium in 1 M HCl solution at 303K and elevated temperatures of 303, 313 and 333K was investigated and compared. The experimental work was performed by the use of weight loss method (gravimetric), hydrogen evolution (gasometric) and electrochemical techniques respectively. The results indicate that both extracts inhibit the corrosion of mild steel in the medium. However, AECAL exhibits higher maximum inhibition efficiency (83.3%) than NAECAL (57.1%) at 2.0 g/L. Generally inhibition efficiency was found to increase with increase in concentration of both leave extracts but decreased with rise in temperature. However, 2.0 g/L concentration showed a better performance in the inhibition of 1M HCl for both samples. Inhibition mechanism was deduced from the temperature dependence of the inhibition efficiency as well as from activation parameters that govern the process. Adsorption of both extracts on the aluminium coupon was found to obey the Langmuir adsorption isotherm. The phenomenon of physical adsorption is proposed from the obtained thermodynamic parameters