ABSTRACT
Corrosion is one of the primary causes of high economic and safety losses around the globe, and various approaches for corrosion inhibition have attained accelerated research attention. In a radical shift from the utilization of traditional toxic corrosion inhibitors, organic inhibitors like drugs, ionic liquids, plant extract, surfactants, biopolymers, and amino acids are being explored as effective alternatives. In addition to the aforementioned inhibitors, rare earth elements also have the potential to inhibit corrosion. The present chapter is a collection of recent research findings that detail the inhibition efficiencies of common organic and inorganic green corrosion inhibitors. Corrosion rate has been effectively deliberated by electrochemical analysis and weight loss method. It has been reported that green corrosion inhibitors could result in inhibition efficiencies as high as 95%, and the performance of these green counterparts was positively enhanced in the presence of the synergistic action of ionic counterparts in lower concentration ranges. Further, the surface of different types of metals with and without the action of inhibitors has been characterized by scanning electron microscopy, atomic force microscopy, contact angle test, energy-dispersive X-ray spectroscopy, etc. Based on experimental evidence, it has been summarized that these green inhibitors harbor heteroatoms that interact with the d orbital of electrons in Fe on the surface of the metal, π electrons present in aromatic loop that interact with the d orbital of electrons in Fe, or electrostatic interaction between the iron and inhibitors to mitigate the loss of metal by corrosion. Further studies on the inhibition mechanism of metal using different types of adsorption isotherm have also been carried out. It has been reported that a Langmuir-type adsorption is prevalent. In essence, their view provides an extensive overview of the existing work in green corrosion inhibitors so as to advance the existing stage of this technology as an industrially adaptable solution.
