S. no. Metal Medium Inhibitor Additive Method Findings Reference 1 Zinc 2 M HCl Aloe vera — Langmuir adsorption isotherm A first-order kinetics relationship [10 ] 2 Mild steel H2 SO4 Aloe vera Infrared spectrophotometer, thermodynamic adsorption theories and gasometric (hydrogen evolution) methods. The study was conducted at 303 and 333 K Chemical adsorption isotherm [11 ] 3 Concrete steel surface 10 or 23 per cent sodium hydroxide Banana plant juice taken from paradica and maghraby banana pseudostem Weight loss method Anticorrosive materials [12 ] 4 Concrete steel surface Magrabe banana stem Galvanostatic polarization technique Mechanical and physic-chemical properties [13 ] 5 Mild steel 1 M HCl Pennyroyal mint Weight loss measurements, electrochemical polarization, and EIS methods Cathodic inhibitor, adsorption isotherm [14 ] 6 Mild steel 1 M HCl Justicia gendarussa extract (JGPE) Weight loss electrochemical techniques. AFM and ESCA Mixed-type inhibitor. Obeys the Langmuir adsorption isotherm [15 ] 7 Mild steel 0.1 M H2 SO4 Caffeic acid Weight loss, potentiodynamic polarisation, electrochemical impedance, and Raman spectroscopy Controls the anodic reaction [16 ] 8 Mild steel 1 M HCl and H2 SO4 Combination of leaves and seeds (LVSD) extracts of phyllanthus amarus Weight loss and gasometric techniques Temkin isotherm [17 ] 9 Carbon steel 1 M HCl Aqueous extracts of mango, orange, passion fruit, and cashew peels Electrochemical impedance, spectroscopy, potentiodynamic polarization curves, weight loss measurements, and surface analysis Langmuir adsorption isotherm [18 ] 10 Carbon stee1 Ethanol Caffeine Voltammograms, Tafel plots, and EIS The standard free energy of adsorption confirms a spontaneous chemical adsorption isotherm step [19 ] 11 Al 0.5 M NaOH Hibiscus sabdariffa leaves Electrochemical measurements Mixed-type inhibitor Langmuir and Dubinin Radushkevich isotherm [20 ] 12 Al-Zn-Mg alloy 0.5 M NaOH HibiscusTeterifa Weight loss measurements The adsorbed molecules of the alloy, lowers the corrosion rate. [21 ] 13 Mild steel H2 SO4 Thyme, coriander, hibiscus, anise, black cumin, and garden cress a.c., d.c., electrochemical techniques, and potentiodynamic polarization Mixed-type inhibitor [22 ] 14 Mild steel Eucalyptus, hibiscus, and agaricus Weight loss and polarization methods Langmuir, Freundlich adsorption isotherm. [23 ] 15 Mild steel 1 M HCl and 0.5 M H2 SO4 Murraya Koenigii leaves Weight loss, EIS, linear polarization, and potentiodynamic polarization techniques Langmuir adsorption isotherm (
,
, and
) [24 ] 16 Mild steel 1 N HCl Murraya Koenigii Weight loss, gasometric studies, electrochemical polarization, AC impedance measurements, and SEM studies (30–80°C) The protective film formed on the surface [25 ] 17 Al 2 M HCl Chromolaena odorata L. Gasometric and thermometric techniques (30–60°C) Langmuir adsorption isotherm [26 ] 18 Mild steel H2 SO4 Ethanol extract of ITHeinsia crinata/IT Weight loss, thermometric, hydrogen evolution techniques, and IR spectroscopy Adsorption inhibitor Temkin and Frumkin adsorption [27 ] 19 Mild steel 1 M HCl 0.5 H2 SO4 Dacryodis edulis (DE) Gravimetric and electrochemical techniques DE extract was found to inhibit the uniform and localised corrosion of carbon steel in the acidic media [28 ] 20 Al HCl Weight loss and hydrogen evolution methods Langmuir adsorption isotherm, activation energies (
), activation enthalpy, and activation entropy [29 ] 21 Al 0.5 M HCl Azadirachta indica (AZI) plantIodide ions Potentiodynamic polarization and impedance techniques Freundlich adsorption isotherm [30 ] 22 Mild steel (60 ppm of Cl− ) Aqueous extract of rhizome (Curcuma longa L.) powder Zn2+ Weight loss method, FTIR, UV fluorescence, and Electrochemical studies Forms synergistic effect, protective film consists of a Fe2+ -curcumin complex and zinc hydroxide (Zn[OH]2 ) [31 ] 23 Al HCl Peepal (Ficus religiosa ). Mass loss and thermometric methods IE dependent upon the concentrations of the inhibitor and the acid [32 ] 25 Mild steel 0.1 M HCl TL and BR inhibitors from green tea and rice bran Weight loss method, polarization techniques Cathodic inhibitor [33 ] 26 Mild steel 0.2 M HCl Bark and leaf solution extracts of mango (Mangifera indica ) Ambient temperature Weight loss method At 1.0 mL/100 mL of 0.2 M dilute sulphuric acid concentration gives good IE [34 ] 27 Mild steel HCl Acid extract of Andrographis paniculata Mass loss method, Tafel polarization method, and impedance studies Plant extract has the potential to serve as corrosion inhibitor [35 ] 28 Al NaOH Abrus precatorius Ambient temperature Weight loss and polarization techniques Suitable adsorption isotherms were tested graphically [36 ] 29 Mild steel H2 SO4 Combretum bracteosum The gravimetric and hydrogen evolution measurements. Temp 30–60°C Frumkin adsorption isotherm [37 ] 30 Al 1 M HCl Root of ginseng Weight loss techniques. Temp 30–60°C IE 93.1% at 30°C at 50% v/v concentration of ginseng Freundlich adsorption isotherm, thermodynamic parameters calculated [38 ] 31 Al 0.5 M NaOH and H2 SO4 Vigna unguiculata (VU) extract Weight loss techniques electrochemical studies. Temp 30 and 60°C Freundlich and Temkin adsorption isotherms [39 ] 32 Mild steel 1 M HCl Mango, orange, passion fruit, and cashew peels Electrochemical impedance spectroscopy, potentiodynamic polarization curves, weight loss measurements, and surface analysis Langmuir adsorption isotherm, IE increases with increasing extract concentration and decreases with temperature [40 ] 33 Mild steel 2 M HCl olive (Olea europaea L.) leaves Weight loss measurements, Tafel polarization, and cyclic voltammetry Langmuir adsorption isotherm, olive extract decreases the charge density in the transpassive region [41 ] 34 Mild steel 5% HCl Both aqueous and alcoholic extracts of seven aloe plants Weight loss measurements IE 70–82% [42 ]
