A critical review on the recent studies on plant biomaterials as corrosion inhibitors for industrial metals

Plant biomaterials as inexpensive, nontoxic, biodegradable materials are found abundantly in nature. They contain heteroatoms and/or pi electrons that make them candidate for metals corrosion inhibitor. In recent years, numerous research works have been undertaken on plant biomaterials as metals corrosion inhibitor in different corrosive media. This review critically looks at the researches done in the years 2013–2018. Corrosive environments covered include acidic, basic, neutral, aqueous, geothermal fluid and artificial saliva. The major findings and the mechanism of inhibition has been elucidated. The missing gap in this area of research has been pointed out and future direction proposed.