Red Arecanut Seed Extract as a Sustainable Corrosion Inhibitor for Aluminum Submerged in Acidic Corrodent: An Experimental Approach Towards Zero Environmental Impact

The effect of the red arecanut seed (RAS) extract on the corrosion of aluminum in 0.5 M hydrochloric acid environment is reported by weight loss, electrochemical (Tafel plot and impedance spectroscopy), scanning electron microscopy and atomic force microscopy studies. The weight loss study indicated that, protection efficiency of the red arecanut seed extract is directly proportional to its concentration and inversely proportional to solution temperature and aluminum contact time in the test solution. Langmuir adsorption isotherm is best fitted model explaining the adsorption of red arecanut seed extract constituents on aluminum surface in 0.5 M HCl system. The results obtained from Tafel curves indicated the mixed inhibition role of red arecanut seed extract. The impedance spectroscopy technique indicated that, red arecanut seed extract reduces the speed of aluminum corrosion by charge transfer process. The scanning electron microscopy and atomic force microscopy images of aluminum specimens clearly give clues about the adsorption of plant constituents on the surface of the aluminum metal

Anti-corrosion properties of areca palm leaf extract on aluminium in 0.5 M HCl environment

The aluminium corrosion inhibition behaviour in the presence of Areca palm leaves (AL) extract in hydrochloric acid (0.5 M) medium was examined by chemical (mass loss), AC impedance spectroscopy, potentiodynamic polarization and surface (scanning electron microscopy) methods. Aluminium protection rates increased with an increase in the amount of AL extract to the 0.5M HCl system and decreased with increasing in the contact time of aluminium metal and temperature of 0.5M HCl solution. Arrhenius equation was applied in the determination of activation energy values. The other activation parameters such as activation entropy and enthalpy values were obtained from the transition state plot. The adsorption of AL extract species on the Al surface in 0.5M HCl solution follows the Langmuir adsorption mechanism. Tafel curves reflect the mixed (both anodic and cathodic) inhibition behaviour of green inhibitor (AL extract species) on electrode surface (Al) in 0.5M system. Impedance method indicates that the Al dissolution in hydrochloric acid environment was fully hindered by charge transfer process. The Al surface morphology was examined by applying scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques.Keywords: Aluminium, Areca palm leaves, weight loss, Arrhenius equation, Langmuir adsorptio

Chemical components of mature areca nut husk extract as a potential corrosion inhibitor for mild steel and copper in both acid and alkali media

<p>Mature areca nut husk (MAH) extract was tested for its efficacy anticorrosive property at electrode–electrolyte interface through chemical and electrochemical techniques. Results of weight loss study show that maximum inhibition action of MAH extracts for copper and mild steel in both acid and alkali media was observed at 303 K with the contact time of 1 hour (94.347% for mild steel in 0.5 M HCl medium, 91.666% for mild steel in 0.5 M NaOH medium, 93.750% for copper in 0.5 M HCl medium, and 90.000% for copper in 0.5 M NaOH medium). Protection efficiency values are inverse relationship with the temperature, which indicates the physical nature of protective film on the metal surface. Adsorption characteristics of the MAH extract on the electrode surface in a hostile fluid environment are consistent with the Langmuir isotherm model under study conditions, which indicates the monolayer formation of inhibitor on electrode surfaces. Results of Tafel study confirm that MAH extract acts as an effective anodic type of inhibitor for the system copper in 0.5 M NaOH system, in the rest of the cases, it acts as a mixed type of inhibitor. From the Nyquist plot, it is clear that increased depressed semicircle area with an increase in MAH extract concentration is an evidence of the inhibitory role of plant extracts on the metal surface. Further, Fourier transform infrared spectroscopy and scanning electron microscopy techniques clearly indicated the protective film-forming ability of the MAH extract on the metal surface.</p