Corrosion Inhibition Potential of a Green Inhibitor “Red Algae” for Copper in 1 M Sulfuric Acid Solution Determined by Electrochemical Measurement, Weight Loss Technique, UV–Visible, FTIR Spectroscopy and Complemented with Surface Analysis (SEM–EDS)

The use of plant extracts as green corrosion inhibitors as replacements for conventional corrosion inhibitors has been the subject of various research in recent years, although their ability to control corrosion still needs to be improved. The fundamental objective of our research is to examine for the first time the inhibitory efficiency of the red alga “Gelidium” against the corrosion of copper in 1.0 M sulfuric acid. Gravimetric and electrochemical methods are used in this investigation. The results obtained show that the compound effectively inhibits the corrosion of copper when it is immersed directly in the corrosive solution comprises the dissolved molecules of the inhibitor. The inhibiting efficiency of this compound increases with its concentration. In fact, from our experiments, we obtained good experimental results with an efficiency reaching 93.75% at 1 M. As a result, we may employ red algae as a powerful inhibitor of copper corrosion in an acidic environment. This inhibitor is cathodic in nature and works by simple adsorption by inhibiting the active sites on the copper surface. The decline in efficiency is a clear indication of the influence of temperature. The confrontation of thermodynamic and kinetic studies allows to propose that the adsorption is of physisorption nature obeys the Langmuir isotherm type. The tests with the scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and UV–visible spectroscopy showed that, under inhibiting circumstances, protective layers were produced.