Ionic Liquids as Green Corrosion Inhibitors for Industrial Metals and Alloys

Present chapter describes recent advances in the field of development of ionic liquids as green and sustainable corrosion inhibitors for metals and alloys. The present chapter has been divided into several sections and subsections. Recently, development of the green and sustainable technologies for the corrosion prevention is highly desirable due to increasing ecological awareness and strict environmental regulations. In the last two decades, corrosion inhibition using ionic liquids has attracted considerable attention due to its interesting properties such as low volatility, non-inflammability, non-toxic nature, high thermal and chemical stability and high adorability. Several types of ionic liquids have been developed as “green corrosion inhibitors” for different metals and alloys such as mild steel, aluminum, copper, zinc, and magnesium in several electrolytic media. The ionic liquids are promising, noble, green and sustainable candidates to replace the traditional volatile corrosion inhibitors

Chitosan-Based Green and Sustainable Corrosion Inhibitors for Carbon Steel

Development of non-toxic and environmental friendly corrosion inhibitors is highly desirable owing to the increasing demands of “green chemistry” throughout the world. In view of these several forms of green corrosion inhibitors such as drugs or medicines, plant extracts, ionic liquids and synthetic inhibitors derived from multicomponent reactions (MCRs) and mechanochemical mixing are being employed. Nowadays, MCRs in association with microwave and ultrasound irradiations represent one of the best green strategies. Natural polysaccharides particularly chitosan derivatives gained substantial advancement. Chitosan and its several derivatives have been employed effective as corrosion inhibitors for metals and alloys in various aggressive media. The present chapter features the collection of major works that have been published on the inhibition effect of chitosan and its derivatives. The utilization of the chitosan and its derivatives as effective corrosion inhibitors is based on the fact that they contain several polar functional groups such as amino (-NH2), hydroxyl (-OH) and acetyl (-COCH3) groups that effectively bind with metallic surface and behave as adsorption centers

2‑Amino-3,5-dicarbonitrile-6-thio-pyridines: New and Effective Corrosion Inhibitors for Mild Steel in 1 M HCl

The corrosion protection efficiency of three pyridines namely 2-amino-3,5-dicarbonitrile-4-(4-methoxyphenyl)-6-(phenylthio)­pyridine (ADTP I), 2-amino-3,5-dicarbonitrile-4phenyl-6-(phenylthio) pyridine (ADTP II), and 2-amino-3,5-dicarbonitrile-4-(4-nitrophenyl)-6-(phenylthio) pyridine (ADTP III) was investigated by electrochemical impedance spectroscopy, potentiodynamic polarization, and weight loss techniques. The results of potentiodynamic polarization studies show that the three compounds under investigation show mixed-type inhibition behavior. Among them, ADTP I shows the highest inhibition efficiency of 97.6% at 1.22 mmol L^–1. The effect of temperature and related activation parameters were worked out. To inspect the surface morphology and composition of inhibitor film on the mild steel surface, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) technique were used

Application of Some Condensed Uracils as Corrosion Inhibitors for Mild Steel: Gravimetric, Electrochemical, Surface Morphological, UV–Visible, and Theoretical Investigations

Gravimetric, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), and potentiodynamic polarization (PDP) studies were carried out to investigate the comparative corrosion protection efficiency of four condensed uracils (CUs) on mild steel in 1 M HCl. EIS plots indicated that the addition of inhibitors increases the charge-transfer resistance (<i>R</i>_ct), decreases the double-layer capacitance (<i>C</i>_dl) of the corrosion process, and hence increases inhibition performance. Moreover, the thermodynamic activation parameters for the corrosion reaction were calculated and discussed in relation to the stability of the protective inhibitor layer. The morphology of the surface was examined by scanning electron microscopy (SEM), and the surface composition was evaluated using energy-dispersive X-ray spectroscopy (EDX) to verify the presence of inhibitor on the mild steel surface. Quantum chemical study suggests that the heterocyclic rings in these compounds are structurally essential for the protection of the mild steel surface

Palmitic acid based environmentally benign corrosion inhibiting formulation useful during acid cleansing process in MSF desalination plants

Palmitic acid imidazole (PI) was synthesized in microwave reactor. The obtained product was explored to reveal the mild steel's corrosion inhibiting property in 1 mol L−1 H2SO4. It gave maximum inhibition efficiency of 90% at ambient condition. Addition of little amount of KI (6 × 10−3 mol L−1) into 1× 10−3 mol L−1 of PI further increased its efficiency up to 98%. High corrosion inhibiting property of PI was observed owing to its adsorption on mild steel surface. The synthesized inhibitor molecule adsorbs via physisorption and chemisorption phenomenon; and followed Langmuir adsorption isotherm. Synergistic effect of KI addition with inhibitors was investigated and the obtained synergism parameters revealed a co-operative mechanism. The surface topography analysis and water angle measurements exhibited surface protective and water repelling property of PI. Furthermore, DFT, FIs analysis, MD simulations and RDF analysis were performed for exploring intrinsic molecular property and insightful elucidation of corrosion inhibiting mechanism. It unveiled spontaneous and strong adsorption of both neutral and protonated PI on metals' surfaces in presence of iodide ions. The obtained outcomes suggested that the combination of KI and PI may be the preferable corrosion inhibitor during acid cleansing process in MSF desalination plants