Eco-friendly guardians: The rise of sustainable corrosion inhibitors

By harnessing nature’s bounty, such as plant extracts, bio-based compounds, and innovative nanotechnologies, vital infrastructure could be protected without compromising environmental integrity, and the Middle East is poised to lead this green revolution

- ABDULAZIZ KHATTAK

IN an era where environmental consciousness drives innovation, sustainable corrosion inhibitors are emerging as vital solutions to protect metals while minimising ecological harm.

Corrosion, the natural degradation of metals through electrochemical reactions with their environment, poses significant challenges across industries, from oil and gas to construction.

Traditional inhibitors, often laden with toxic chemicals like chromium, have been effective but environmentally detrimental.

The shift towards green alternatives, particularly plant-based extracts, offers a promising path to balance industrial needs with sustainability.

Corrosion inhibitors are substances applied in small quantities to metal surfaces or corrosive media to reduce degradation.

Historically, toxic compounds dominated this field, but recent research has pivoted towards eco-friendly alternatives derived from natural sources.

Plant extracts, rich in phytochemicals like flavonoids, phenols, and alkaloids, have shown remarkable efficacy in protecting metals such as steel, copper, and aluminium.

These compounds work by adsorbing onto metal surfaces, forming protective films that block reactive sites.

The Langmuir adsorption model, which describes a monolayer adsorption process, is commonly observed, with electron-rich heteroatoms (nitrogen, oxygen) facilitating chemisorption, while polar regions drive physisorption.

A 2020 review by Miralrio and Vazquez highlights the efficacy of plant extracts, noting inhibition efficiencies often exceeding 80-90 per cent for metals like mild steel in aggressive media such as 1 M HCl.

Extracts from plants like Eucalyptus, green tea, and Rosa canina have demonstrated mixed-type inhibition, simultaneously mitigating anodic and cathodic reactions.