Sargassum muticum extract based on alginate biopolymer as a new efficient biological corrosion inhibitor for carbon steel in hydrochloric acid pickling environment: Gravimetric, electrochemical and surface studies

• Published in: International journal of biological macromolecules 2019-12, Vol.141, p.137-149
• Main Authors: Nadi, I., Belattmania, Z., Sabour, B., Reani, A., Sahibed-dine, A., Jama, C., Bentiss, F.
• Format: Article
• Language: English
• Subjects: Alginates - chemistry; Biological macromolecules; Carbon steel; Chemical Sciences; Corrosion; Eco-friendly corrosion inhibitor; EIS; Electrochemical Techniques; HCl; Hydrochloric Acid - chemistry; Material chemistry; Polymers; Sargassum - chemistry; Sargassum muticum; Steel - chemistry; Surface Properties; XPS
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2019.08.253

The inhibition effect of the invasive brown seaweed Sargassum muticum extract (ESM), harvested from the Atlantic coast of Morocco, against the corrosion of carbon steel (CS) in 1 M HCl medium was studied for the first time using gravimetric, electrochemical and surface techniques. The methanolic crude extract of Sargassum muticum (ESM) is rich in alginate biopolymer. The evaluation corrosion tests showed that this algal extract acts as a good mixed corrosion inhibitor for CS substrate in 1 M HCl since inhibition efficiency of 97% was reached with 1 g/L of ESM at 303 K. AC impedance findings showed that the seaweed extract adding in the corrosive electrolyte increases the polarization resistance and conversely decreases the charge capacitance at the interface. Adsorption of ESM on the substrate surface followed the Langmuir adsorption isotherm. X-ray photoelectron spectroscopy analyses (XPS) demonstrated that the corrosion inhibition mechanism of CS substrate in 1 M HCl environment by the investigated algal extract is typical of the chemisorption process and the protective barrier is mainly formed by the adsorbed biological macromolecules. •The Sargassum muticum extract (ESM) is an effective biological inhibitor for the carbon steel corrosion in 1 M HCl.•The adsorption of ESM biological macromolecules on the steel surface is best described by the Langmuir model.•ESM is chemisorbed on the steel surface.•XPS analysis has provided the composition of adsorbed protective layer on the steel surface.