Combined experimental and computational analysis of green Vachellia Nilotica as a mild steel corrosion inhibitor in acidic medium.

Corrosion inhibition of mild steel in 1 mol/L HCl by amoxicillin and ceftriaxone in the concentration range of 1.00x10(-5)-1.00x10(-2) mol/L has been studied using weight loss, electrochemical potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and quantum chemistry tests at 298 K. The weight loss experiment showed that the inhibition efficiency increased with amoxicillin and ceftriaxone concentrations to attain the maximums of 80.3% and 94.1%, respectively at 1.00x10(-2) mol/L. Potentiodynamic polarization indicated that amoxicillin and ceftriaxone acted as mixed-type inhibitors but mainly inhibited cathode hydrogen evolution reaction for mild steel in 1 mol/L HCl. The electrochemical impedance spectroscopy (EIS) demonstrated the inhibitors covered the active points of metal surface to inhibit corrosion. The absorption of both inhibitors on the mild steel surface was found to follow Langmuir adsorption isothermal and dominantly involve chemical adsorption at 298 K. Scanning electron microscopy (SEM) confirmed both of the inhibitors played a significant protective effect in mild steel corrosion in 1 mol/L HCl. The relationship between the inhibition properties and molecular structure had been discussed by quantum chemistry calculation. All the experimental results concluded that both amoxicillin and ceftriaxone acted as good corrosion inhibitors and their inhibition efficiency was in the order of ceftriaxone > amoxicillin.

The present study investigated the adsorption and inhibition behavior of leaf extract of Tephrosia Purpurea (T. purpurea) on mild steel corrosion in 1 N H2SO4 solution using electrochemical and surface morphological methods. Techniques adopted for electrochemical studies were Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS) technique; and surface morphological studies were carried out using Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). The leaf extract of T. purpurea was characterized using UV-Visible spectroscopy (UV-Vis), Fourier-Transform Infrared Spectroscopy (FT-IR), Nuclear Magnetic Resonance Spectroscopy (NMR) and Gas Chromatography – Mass Spectrometry (GCMS). The results obtained from electrochemical studies exhibited the potential of T. purpurea as good corrosion inhibitor. And, it was found that, the inhibition efficiency (I.E in %) increases with increase in concentration of the inhibitor molecules, the optimum inhibitor concentration observed was 300 ppm and the inhibition efficiency of 93% was observed at this inhibitor concentration. Above 300 ppm, there was not much changes in inhibition efficiency. Polarization studies provided the information that the inhibition is of mixed type and EIS confirmed that the corrosion process is controlled by single charge transfer mechanism. And, it was obtained that, the adsorption of inhibitor molecules obeys Langmuir adsorption isotherm. The inhibition is mainly by the adsorption of inhibitor molecules on the mild steel electrode surface, which was confirmed by FT-IR, SEM and AFM studies. Through all the experimental results, it can be arrived that, the leaf extract of T. purpurea performed as a good corrosion inhibitor for mild steel in 1 N sulfuric acid medium.

Nitrogen-containing heterocyclic organic compounds have been found to be effective in corrosion inhibitors, especially in hydrochloric acid media. The purpose of this study is to investigate the inhibition performance of N1, N1, N5, N5-tetrakis ((1H-pyrazol-1-yl) methyl) naphthalene-1, 5-diamine (NPD) on mild steel in 1 M HCl solution. The inhibitive action of this compound against the corrosion of mild steel in 1 M HCl solution has been investigated using weight loss measurements, Tafel Polarization and electrochemical impedance spectroscopy (EIS) techniques. The results obtained from the different corrosion evaluation techniques are in good agreement. Results obtained reveal that this compound performs excellently as corrosion inhibitor for mild steel in HCl 1M solution. The temperature effect on the corrosion behavior of mild steel in 1 M HCl with and without product at different concentrations was studied in the temperature range from 313 to 343 K. The adsorption free energy and activation parameters for the mild steel dissolution reaction were determined. Adsorption of this inhibitor on the mild steel surface in 1M HCl follows the Langmuir isotherm model. The surface characteristics of inhibited and uninhibited mild steel were investigated by scanning electron microscopy (SEM) and EDX studies. Quantum chemical approach, using the density functional theory (DFT)at B3LYP/6-31G (d,p) level, was realized in order to explain the inhibitory action and to get a better understanding about the relationship between the inhibition efficiency and molecular structure of NPD and the calculated quantum chemical parameters were discussed. The theoretical results were found to be consistent with the experimental data.

Kopsia terengganensis’ alkaloids as potential green inhibitors for mild steel corrosion in CO2-saturated 3.5% NaCl medium

A comprehensive study of ondansetron hydrochloride drug as a green corrosion inhibitor for mild steel in 1 M HCl medium

In this study, a novel epoxy resin called tetraglycidyl ether of methyl-α-D-mannopyranoside (TGEMM) was synthesized and investigated for its potential used as a corrosion inhibitor for mild steel in a 1.0 M hydrochloric acid (HCl) solution. The main goal was to evaluate the corrosion inhibition properties of TGEMM using various techniques. The methods used in this research included potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), temperature effect, scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy and contact angle measurement. These techniques were chosen to comprehensively assess the corrosion inhibition performance of TGEMM on MS. In this context, the structure of the newly synthesized TGEMM epoxy resin was identified and confirmed using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The results obtained from the experiments demonstrated that, at a lower concentration of 10−3 M, TGEMM demonstrated a high inhibitory efficacy of 91.49%, assessed via electrochemical impedance spectroscopy (EIS), and 93.84%, measured via potentiodynamic polarization (PDP), in a 1.0 M hydrochloric acid solution. The PDP data indicated that the TGEMM epoxy resin acted as an anodic inhibitor in the acidic environment. In addition to gain insights into the interaction mechanism and adsorption mode, DFT and MD simulations were conducted, revealing valuable information about the interaction of TGEMM with the mild steel surface.

Corrosion in API 5L steel under 1M HCl is a common issue; hence, creating a more effective and naturally-based inhibitor is critical. In this research, Syzygium Cumini leaf extract (SCLE) was used as a new green corrosion inhibitor under acidic conditions. The inhibition properties of the novel cumini extract were thoroughly characterized using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), Fourier-transform infrared spectroscopy (FTIR), and atomic force microscope (AFM). The results show that the cumini inhibitor has excellent corrosion inhibition with 93 % inhibition efficiency. The adsorption behavior of the inhibitor follows the Langmuir Adsorption Isotherm due to the nearness of R2 to unity. The potentiodynamic and electrochemical measurements demonstrate the mixed type of corrosion inhibitor. Thermodynamic calculation of ΔGads is – 18.41 kJ mol-1 showing the physical adsorption process between the inhibitor and metals. Further inspection of ΔHads at ‒58.93 kJ mol-1 considers releasing energy during adsorption. The FTIR results agree with the increased growth of passive layers due to the adsorption of polyphenol and flavonoids on metals. Remarkably, the adsorption peak at 3266.59 cm-1 corresponds to the adsorption of –OH. The peak at 1612.56 and 1698.4 cm-1 is attributed to C=C and C=O functional groups. The above functional groups serve as adsorption centers to reduce the corrosion effect. The surface treatment of AFM indicated a good relationship with the functional group characterization and confirmed the significant corrosion rate reduction. This work can be used as a benchmark to develop a natural plant as a corrosion inhibitor.

Cysteine based silver-gold nanocomposite (Cys/Ag-Au NCz) was synthesized, this was followed by its characterization using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Ultraviolet-visible spectroscopy (UV-Vis), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDAX), Thermogravimetric analysis (TGA) and Transmission electron microscopy (TEM). Cys/Ag-Au NCz was studied as novel green corrosion inhibitor for mild steel in 1M HCl solution at varying concentration and temperature using gravimetric, Potentiodynamic polarization (PDP), Electrochemical impedance spectroscopy (EIS), SEM, EDAX and FTIR. Weight loss, PDP and EIS studies confirmed Cys/Ag-Au NCz as efficient corrosion inhibitor at moderately low concentration. The maximum inhibition efficiency of 96 % was observed at 303 K at 300 ppm. Cys/Ag-Au NCz acted by affecting both anodic and cathodic processes and its adsorption on steel surface followed the Langmuir adsorption isotherm. EIS data displayed the existence of protective film at mild steel/solution interface in Cys/Ag-Au NCz inhibited system. SEM micrograph in presence of Cys/Ag-Au NCz inhibited acid solution displayed better morphology as compared to blank solution. The UV-Vis and FTIR data indicates good interaction between the Cys/Ag-Au NCz and steel surface.

Detailed atomic/molecular-level/electronic-scale computer modeling and electrochemical explorations of the adsorption and anti-corrosion effectiveness of the green nitrogen-based phytochemicals on the mild steel surface in the saline solution

Aminomethylpyridazine isomers as corrosion inhibitors for mild steel in 1 M HCl: Electrochemical, DFT and Monte Carlo simulation studies

Low cost aqueous extract of Pisum sativum peels for inhibition of mild steel corrosion

Schiff bases, alternative anticorrosive additive wassynthesized, characterized and investigated for the inhibition of mild steel corrosion in 1M Hydrochloric acid at concentrations of 20 ppm, 40 ppm, 60 ppm, 80 ppm and 100 ppm using weight loss (WL) and electrochemical methods. The novel Schiff base ligands obtained were characterized by Ultraviolet-visible and Fourier-Transform Infrared Spectroscopy. The elemental analysis data for the Schiff base ligands were used to confirm the general formula of the Schiff bases. Fourier-Transform Infrared spectroscopy provided evidence of formation of a complex surface film due to adsorption of the Schiff bases on the mild steel surface. Maximum inhibition efficiency for Schiff base ligand 1 (SBL1) and Schiff base ligand 2 (SBL2) obtained were respectively 76.92% and 86.21% at concentrationof100ppm,andthetrendfollowedSBL2>SBL1, indicating the effectiveness of SBL2 in corrosion prevention as compared SBL1. Potentiodynamic polarization(PDP) measurements showed that the Schiff bases acted as mixed type inhibitors. Electrochemical Impedance Spectroscopic (EIS) measurement revealed that the corrosion process was controlled by charge transfer process. Inhibition efficiency values obtained from the different techniques were comparable. Quantum chemical parameters such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital(LUMO) and energy gap (ΔE) were obtained using Hartree-fock Density Functional Theory by Hamiltonian method. The results showed that SBL2 was more reactive than SBL1. In conclusion, the inhibition of mild steel corrosion was due to adsorption of active molecules leading to formation of a protective layer on surface of mild steel.

Moroccan, Mauritania, and senegalese gum Arabic variants as green corrosion inhibitors for mild steel in HCl: Weight loss, electrochemical, AFM and XPS studies

The pervasive corrosion of mild steel in acidic media poses a significant challenge in various industrial applications. While existing synthetic corrosion inhibitors are effective, their high cost and environmental toxicity necessitate the development of more sustainable alternatives. In this study, we present a novel approach to corrosion mitigation employing a porous nanocarbon synthesized from mango kernels, a sustainable source of agricultural waste. The CNS inhibitor was synthesized via pyrolysis at 800 °C, yielding a high surface area (1090.2 m2 g−1) as confirmed by BET analysis. FE-SEM revealed a well-developed spherical morphology with an average particle size of 60–70 nm. The corrosion inhibition efficiency of CNS was evaluated for mild steel in 1 M HCl using a combination of electrochemical techniques, including open circuit potential, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy. The CNS derived from waste mango kernels, exhibited excellent inhibition performance, achieving an efficiency of up to 87.1% at 800 ppm. PDP results revealed a mixed-type inhibition mechanism with suppression in both anodic and cathodic reactions. The thermodynamic parameter, adsorption free energy () of about −20.0 kJ mol−1, indicates a spontaneous process and predominantly physical adsorption. Adsorption behavior was consistent with the Langmuir isotherm model. Surface analyses using SEM, EDS, optical profilometry, and water contact angle measurements corroborated the formation of a protective inhibitor film on the steel surface. These findings highlight the potential of bio-waste-derived materials as a sustainable and environmentally benign corrosion inhibitor for mild steel in acidic environments.

The corrosion inhibition of mild steel in 0.1M HCl solution by 4-hydrobenzoic acid was studied at temperature range 303, 313, 323 and 333 K using weight loss measurement, thermometric, Polarization Resistance, Potentiodynamic Polarization, Electrochemical Impedance Spectroscopy, Scanning Electron Microscopy (SEM) and Fourier transformed infra-red spectroscopy (FTIR) techniques. The results obtained at 303 K indicated that the studied inhibitor had established >88% inhibition efficiency at an optimum concentration of 0.10 M. The adsorption of 4-hydrobenzoic acid takes place according to Langmuir`s adsorption isotherm. Kinetic parameters (activation energy, Ea and pre-exponential factor, A) as well as thermodynamic parameters (enthalpy, entropy and free energy of adsorption; ΔHads o ΔSads o, and ΔGads o respectively) were calculated and discussed. Potentiodynamic polarization studies indicate that 4-hydrobenzoic acid acts as a mixed type of inhibitor. Data collected from EIS studies has been analyzed to model the appropriate equivalent circuit for better explanation of corrosion inhibition process. The surface analysis study using SEM confirms the corrosion of the mild steel and its inhibition by the inhibitor. FTIR spectra of the inhibitor and the corrosion product of mild steel (in the presence of the inhibitor) reveal that there were shifts in frequencies of adsorption suggesting that some functional groups were used in adsorption and some new bonds were formed.