An overview on plant extracts as environmental sustainable and green corrosion inhibitors for metals and alloys in aggressive corrosive media

Evaluation of Thymus vulgaris plant extract as an eco-friendly corrosion inhibitor for stainless steel 304 in acidic solution by means of electrochemical impedance spectroscopy, electrochemical noise analysis and density functional theory

A simple, eco-friendly, and biomimetic approach using Thymus vulgaris (T. vulgaris) leaf extract was developed for the formation of ZnO-Ag nanocomposites (NCs) without employing any stabilizer and a chemical surfactant. T. vulgaris leaf extract was used for the first time, in a novel approach, for green fabrication of ZnO-Ag NCs as a size based reducing agent via the hydrothermal method in a single step. Presence of phenols in T. vulgaris leaf extract has served as both reducing and capping agents that play a critical role in the production of ZnO-Ag NCs. The effect of silver nitrate concentration in the formation of ZnO-Ag NCs was studied. The in-vitro Antimicrobial activity of NCs displayed high antimicrobial potency on selective gram negative and positive foodborne pathogens. Antioxidant activity of ZnO-Ag NCs was evaluated via (2,2-diphenyl-1-picrylhydrazyl) DPPH method. Photocatalytic performance of ZnO-Ag NCs was appraised by degradation of phenol under natural sunlight, which exhibited efficient photocatalytic activity on phenol. Cytotoxicity of the NCs was evaluated using the haemolysis assay. Results of this study reveal that T. vulgaris leaf extract, containing phytochemicals, possess reducing property for ZnO-Ag NCs fabrication and the obtained ZnO-Ag NCs could be employed effectively for biological applications in food science. Therefore, the present study offers a promising way to achieve high-efficiency photocatalysis based on the hybrid structure of semiconductor/metal.

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Novel Green Biomimetic Approach for Synthesis of ZnO-Ag Nanocomposite; Antimicrobial Activity against Food-borne Pathogen, Biocompatibility and Solar Photocatalysis.

Corrosion inhibition analysis and adsorption behaviour of fruits extract of Myristica fragrans for mild steel in 0.5 M H2SO4 solution has been estimated utilizing weight loss, EIS, Tafel, UV, IR, SEM, AFM and Quantum chemical calculations. The presence of several phytochemical constituents in the extract of Myristica fragrans decreases the corrosion rate of mild steel in acidic medium. The best inhibition efficiency of 87.81% was obtained at 500 mg/L inhibitor concentration.

Myristica fragrans extract as an eco-friendly corrosion inhibitor for mild steel in 0.5 M H2SO4 solution

Recently, research studies in the fields of science and engineering are directed towards the synthesis, design, development, and consumption of environment-friendly chemical species to replace traditional toxic chemicals. This is because of the escalating demands of conservation understanding and stringent ecological rules. Currently, various environment-friendly alternatives derived from natural resources such as biopolymers, plant extracts, chemical medicines (drugs), etc. are widely used to replace toxic corrosion inhibitors. Moreover, various biopolymers in their pure and modified forms are extensively employed as environment-friendly corrosion inhibitors. Compounds derived through multicomponent reactions (MCRs), and microwave (MW) and ultrasound (US) irradiations are also considered as environment-friendly alternatives. Polyethylene glycol (PEG) and ionic liquids (ILs) possess low vapor pressure and are regarded as designer environment-friendly alternatives. The chemicals synthesized using green solvents such as water, ILs and supercritical CO2 can also be regarded as environment-friendly chemical species. A comprehensive literature survey reveals that these compounds are extensively utilized as metallic corrosion inhibitors in various corrosive electrolytes. Overall, this review provides a summary of several major reports on environment-friendly corrosion inhibitors.

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Yasmin Al Mowaqet

Papers

The effect of Thyme leaves extract on corrosion of mild steel in HCl