Chitosan as an Environmentally Friendly Corrosion Inhibitor—A Review

Abstract Corrosion poses a significant challenge for industries such as automotive, marine, construction, and oil and gas, as it impacts the production of high-quality goods while keeping maintenance costs low. Corrosion reactions, including oxidation and reduction on metal surfaces, can be mitigated using corrosion inhibitors. Traditionally, chromate and phosphate-based compounds have been employed in various sectors to prevent these reactions. However, concerns about their toxicity and environmental impact have spurred the search for non-toxic alternatives. Chitosan (CT), a biodegradable and renewable material derived from chitin, shows promise as a corrosion inhibitor due to its film-forming ability and antimicrobial properties. Its hydroxyl and free amino groups enhance its effectiveness in various corrosive environments, making CT suitable for protecting metals across different industries. Previous research has explored the use of CT-based composites and standalone CT materials as coatings on metal surfaces. Both types have also been tested directly in corrosive environments, demonstrating promising results for protecting various metals from corrosion in different corrosive media. This review article aims to investigate the application and mechanism of CT as a corrosion inhibitor. It discusses the preparation methods, application techniques, and performance of CT as an anticorrosive material, concluding with an explanation of its corrosion inhibition mechanism. This review is intended to enhance researchers' understanding of CT's potential in corrosion inhibition and support its further development as an effective corrosion inhibitor.