Corrosion Inhibition Of Mild Steel Research Articles

Corrosion inhibitive performance of Kopsia teoi extracts towards mild steel in 0.5 M HCl solution

This study investigates the capacity of Kopsia teoi (K. teoi) to inhibit corrosion, employing its stem extracts to prevent mild steel (MS) corrosion in 0.5 M HCl. In this study, three distinct extracts: dichloromethane alkaloid (KTDAE), dichloromethane non-alkaloid (KTDNAE), and methanol (KTME) were employed to investigate their corrosion mitigation performance, involving electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD) techniques. EIS results demonstrated a significant increase in inhibition efficiency with concentration for each extract, reaching 87.04, 90.62, and 93.51 % for KTDAE, KTDNAE, and KTME, respectively. According to PD analysis, Kopsia teoi extracts (KTEs) functioned as mixed-type inhibitors. Surface analysis through scanning electron microscopy-energy dispersive X-ray spectroscopy exhibited notable improvements in the morphology of treated MS plates, revealing the establishment of a protective surface film. Langmuir isotherm confirmed that KTEs formed a monolayer on MS surface, and the calculated free energies of adsorption were −25.924, −26.809, and −27.687 kJ mol−1 for KTDAE, KTDNAE, and KTME, respectively. This suggests effective adsorption through both physisorption and chemisorption mechanisms. Consequently, the results of this study highlight the encouraging effectiveness of KTEs as corrosion inhibitors for MS in acidic environments.

Methanol extract of Murraya koenigii stem as green inhibitor for mild steel corrosion in 1 M HCl solution

In this work, methanol extract of Murraya koeginii stem has been studied as an ecofriendly inhibitor against mild steel corrosion in 1 M hydrochloric acid medium. Ultraviolet–visible and Fourier transform infrared spectroscopic tools were employed to characterize the extract. Corrosion inhibition efficacy of the extract against mild steel was studied in terms of weight loss method and electrochemical measurement method. Weight loss measurement shows the inhibition efficiency of 94.95 % for the first 6 h of immersion time and maximum efficiency of 96.39 % for 24 h immersion time using 1000 ppm inhibitor solution. Electrochemical measurement shows that for the same concentration of inhibitor, inhibition efficiency is 81.54 % in as-immersed condition whereas it is 85.76 % in 1 h immersed condition. Free energy of the adsorption reflected the physisorption followed by chemisorption. Similarly, thermodynamic parameters revealed the feasibility and spontaneity of the adsorption. Obtained results showed that the methanol extract of Murraya koeginii stem can be a potential corrosion inhibitor.

BF2 complexes of pyridyl‐isoindoline‐1‐ones as an efficient corrosion inhibitor for mild steel in 1 M HCl and the application for surgical instruments anticorrosion

AbstractIn this study, BF2 complexes of pyridyl‐isoindoline‐1‐ones (BPIO) has been firstly designed and investigated as an excellent corrosion inhibitor for the mild steel in 1 M HCl. The corrosion protection properties of BPIO were studied by using a series of experiments. The results indicated BPIO has excellent inhibition performance, and inhibition efficiency of BPIO reached up to 96.6%. The effects of immersion temperature and time were investigated by weight loss experiments to evaluate the stability of adsorbed BPIO film in protecting steel surface. Based on potentiodynamic polarization studies, BPIO acted as one mixed‐type corrosion inhibitor with predominant anodic effectiveness, and its adsorption on the mild steel follows the Langmuir adsorption isotherm. The values of ΔGads suggested the adsorption of BPIO on the mild steel surface was through a combination of chemisorption and physisorption. The adsorption of BPIO molecules on the steel surface was further identified by the techniques of scanning electron microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS). The quantum chemical calculations based on density functional theory (DFT) and molecular dynamics (MD) simulations were used to optimize the BPIO molecular structure and investigate the inhibitive properties on the theoretical level, which agreed well with the experimental results. Besides, BPIO has been used for the development of water soluble metal antirusting agent.

Insights of newly synthesized novel pyrazole compounds for mild steel corrosion inhibition in an acidic environment by experimental and computational calculations

Pyrazole derivative Ethyl (E)-2-cyano-3-(1,3-diphenyl-1H-pyrazol-4-yl)acrylate (Pz-a) and its novel nitro derivative Ethyl (E)-2-cyano-3-(3-(3-nitrophenyl)-1-phenyl-1H-pyrazol-4-yl)acrylate (Pz-b) were synthesized and characterised using Mass spectra, IR, 1H NMR, 13C NMR and utilized to safeguard mild steel from degradation in 1 M Hydrochloric acid environment. The inhibition effectiveness and mechanism were examined through both experimental and theoretical calculations. Electrochemical analysis illustrate that the protective property of pyrazoles rises proportionally with concentration. Potentiodynamic polarization reveals, both pyrazoles exhibit characteristics of mixed type inhibitors, inhibiting both oxidation and reduction processes. Pz-a and Pz-b adhesion on mild steel surface resembles the Langmuir isotherm. Gibbs free energy of adsorption (ΔGads) indicates Pz-a and Pz-b adsorbs physically and chemically over metal surface. The inhibition efficiency was found to be 89.85 % for Pz-b and 84.47 % for Pz-a at 10−2 M concentration. AFM scanning further confirms that the inhibitors are confined over mild steel. Better understanding of the corrosion inhibition mechanism has been facilitated by theoretical investigations through DFT parameters.

Corrosion Inhibition of Mild Steel in 1.0 M HCl from Thiadiazole Derivative Schiff Bases and Their Complexes with Co(II) and Ni(II): Synthesis, Characterization, DFT Study, and Monte Carlo Simulation

Corrosion Inhibition of Mild Steel in 1.0 M HCl from Thiadiazole Derivative Schiff Bases and Their Complexes with Co(II) and Ni(II): Synthesis, Characterization, DFT Study, and Monte Carlo Simulation

Investigations of corrosion inhibition of ethanolic extract of Dillenia suffruticosa leaves as a green corrosion inhibitor of mild steel in hydrochloric acid medium

The utilization of plant extracts as environmentally friendly corrosion inhibitors has garnered considerable interest in the field of metallic corrosion protection. The primary objective of this study was to explore a new approach for utilizing Dillenia suffruticosa leaves extract (DSLE) to provide corrosion protection for mild steel (MS) in a molar hydrochloric acid solution. The phytocompounds responsible for corrosion prevention were extracted using ethanol with Soxhlet apparatus. The effectiveness of the extract as a corrosion inhibitor was evaluated through gravimetric and electrochemical methods, along with surface analysis of the corroded steel samples. This analysis involved the use of scanning electron microscopy (SEM) and Fourier-transformed infrared spectroscopy (FTIR) to examine the specimens with and without addition of the extract as inhibitor. The findings demonstrate that DSLE exhibits notable efficacy as a corrosion inhibitor for MS in an acidic environment. The inhibition efficiency (IE) demonstrates a positive correlation with the concentration of the extract, ultimately reaching a maximum value of 81.4% at the optimum concentration of 1000 mg/L of the extract investigated. Potentiodynamic polarization data revealed that the DSLE functions as a mixed-type inhibitor.

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

The corrosion inhibition potential of alkaloids from Kopsia terengganensis bark extract (KTBE) in mitigating the mild steel corrosion in a CO2-saturated 3.5% NaCl medium was evaluated. Standard corrosion evaluation methods, including weight loss test, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PD) were employed, which revealing a concentration-dependent enhancement in KTBE's inhibition efficiency. At 500 ppm, the corrosion inhibition efficiency recorded the highest value of 90.63% based on the weight loss study and 87.38% based on electrochemical analysis. Tafel slopes in PD studies affirmed that KTBE functioned as an anodic-type inhibitor. The adsorption of the inhibitor is in accordance with the Langmuir adsorption isotherm with an adsorption free energy (ΔG°ads) of −26.47 kJ/mol, suggesting the binding of KTBE molecules by means of physisorption. Surface analysis conducted through scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, and Fourier transform infrared spectroscopy (FTIR) confirmed the formation of a protective inhibitive layer on the surface of mild steel. The proposed corrosion inhibition mechanism involves electrostatic interactions between KTBE molecules and the mild steel surface. This comprehensive investigation underscores KTBE's potential as an effective corrosion inhibitor in corrosive environments.

Azide Assisted Corrosion Inhibition of Mild Steel by Bioactive Metallic Complexes – A Quantum Chemical Investigation

Azide Assisted Corrosion Inhibition of Mild Steel by Bioactive Metallic Complexes – A Quantum Chemical Investigation

Adsorption studies of isoxazole derivatives as corrosion inhibitors for mild steel in 1M HCl solution: DFT studies and molecular dynamics simulation.

The corrosion of mild steel is a significant issue in various industries, prompting the need for effective corrosion inhibitors. This study focuses on understanding the corrosion inhibition properties of organic compounds derived from isoxazole, namely series Iso(a), Iso(b), Iso(c), Iso(d), Iso(e), Iso(f), Iso(g), and Iso(h), which could have implications for materials science and industrial applications. By investigating the influence of different substitutions on these compounds, valuable insights can be gained into designing better corrosion inhibitors for practical use. Theoretical studies were conducted using density functional theory (DFT) with the B3LYP functional and the 6-31G (d,p) basis set. These calculations enabled the evaluation of various parameters including frontier orbital energies (EHOMO, ELUMO), energy gap (∆E), electronegativity (χ), absolute hardness (η), softness (σ), fraction of transferred electrons (∆N), as well as local properties such as natural atomic populations and Fukui indices. Additionally, molecular dynamics simulations were performed to study the adsorption behavior of the inhibitors on the surface of Fe (110). The simulations were conducted using Materials Studio version 8.0 software package using COMPASS force field to understand the impact of different functional groups on the inhibitors before and after adsorption on the iron surface.

Polyethyleneglycol bisphenol A epichlorohydrin copolymer (PEG-BEC) as a highly efficient inhibitor for mild steel corrosion in 1M HCl solutions

In this work, the corrosion inhibition performance of polyethyleneglycol bisphenol A epichlorohydrin copolymer (PEG-BEC) against mild steel in 1 M HCl was studied by electrochemical and weight loss techniques. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX) were applied to characterize the surface morphology of the mild steel samples. The corrosion mitigation efficiency was observed to rise as the concentration of PEG-BEC rises in the corrosive medium while increasing the temperature (25 °C -65 °C) resulting in a drop in the inhibition ability. Furthermore, under hydrodynamic conditions, the corrosion of the mild steel was found to deteriorate both in the absence and presence of PEG-BEC. Just with 10 ppm, an inhibition efficiency (IE) of 97.6% was obtained at 25 °C by EIS. PEG-BEC acts as a mixed-type inhibitor as observed by potentiodynamic polarization (PDP) technique. The observed corrosion inhibition action of PEG-BEC could be ascribed to the adsorption of the molecules and the formation of a protective film on the steel surface as evidenced by static water contact angle (WCA). Langmuir isotherm best describes the PEC-BEG-metal adsorption with large Kads values indicating a thermodynamically stable nature inhibition process. The obtained ∆G°ads = -35.138 to -39.522 kJ/mol indicate that the PEG-BEC spontaneously adsorbed onto the steel with strong tendency to provide protection to the mild steel surface via combination of chemisorption and physisorption processes. The ΔHads -53.07 kJ/mol and ΔSads= +0.048 kJ/mol-k, respectively, suggests an exothermic reaction accompanied by relatively increase in entropy of the PEG-BEC adsorption on the mild steel surface.

Inhibition of Mild Steel Corrosion by New Epoxy Resin in 1 M HCl: Synthesis, Characterization, Experimental Study and Theoretical Approach

Inhibition of Mild Steel Corrosion by New Epoxy Resin in 1 M HCl: Synthesis, Characterization, Experimental Study and Theoretical Approach

UV radiation effect on the corrosion inhibition potential of Helichrysum kraussii plant extract on mild steel metal in sulphuric acid medium

The comparison of the effect of UV-radiated and non-radiated Helichrysum kraussii (H. kraussii) extracts was studied for mild steel corrosion in 1.0 M H2SO4 at 30–60 °C using Liquid chromatography-mass spectrometry (LCMS), gravimetric weight loss analysis, electrochemical analysis and Fourier Transform Infrared spectroscopy (FTIR). The LCMS confirmed the trans-to-cis shift geometrical isomerisation for H. kraussii due to UV radiation. From the gravimetric analysis data, the corrosion rate was calculated and found to be decreasing with an increase in the concentration of the inhibitor extracts, with the highest concentration at 30 °C having a corrosion rate of 3.920x10-4 and 1.700x10-4 g.cm2.h−1 for UV-radiated. Non-radiated H. kraussii extract gave the highest inhibition efficiency of 96.663 % compared to 92.503 % of the UV-radiated H. kraussii extract. The semi-circles diameter of the Nyquist plot from the electrochemical impedance spectroscopy (EIS) was found to increase with an increase in the inhibitor concentration, suggesting the increase in inhibition with an increase in the concentration of the two extracts. Functional groups such as C = C, O-H, and N-H, known to be functional groups of the most effective corrosion inhibitors, were observed for both extracts from FTIR. Based on the results obtained, it was found that the UV-radiated H. kraussii extract was more effective in inhibiting the corrosion of mild steel in sulphuric acid than the non-radiated H. kraussii extract. This suggests that UV radiation decreases the efficiency of the H. kraussii extract as a corrosion inhibitor for mild steel in H2SO4. Therefore, it is recommended that the H. kraussii extract be used only as a corrosion inhibitor for mild steel in 1.0 M H2SO4 in its original state without being exposed to UV radiation.

Bio-based ionic liquid as a corrosion inhibitor for mild steel in 5% HCl solution: Experimental and theoretical investigation

In pickling conditions, corrosion inhibitors are commonly used to mitigate the corrosive effects of the acidic environment on metal surfaces. Green corrosion inhibitors are substances that provide corrosion protection while being environmentally friendly, often derived from renewable resources or having minimal environmental impact. Ionic liquids are a class of green corrosion inhibitors that have gained attention for their potential in corrosion protection due to their unique properties. In this study, we synthesized a bio-based choline hexanoate ionic liquid (referred to as ChH) and used FT-IR and 1H NMR spectroscopy to elucidate its structure. Further the effectiveness of ChH IL was examined in preventing MS corrosion in 5% HCl at 20–80 °C. The corrosion behavior of MS was examined using weight loss, potentiodynamic polarization, and EIS measurements. Increasing inhibitor concentration and temperatures improved the inhibition performance. The highest efficiency i.e., 98.16% was observed at 3.3 × 10−3 M of ChH at 60 °C. To verify the adsorption of ChH on the MS further investigations were done using FT-IR, Raman, and XPS analysis.

Experimental and theoretical insights into Artemisia Stems aqueous extract as a sustainable and eco-friendly corrosion inhibitor for mild steel in 1M HCl environment.

The present research demonstrates an innovative investigation of environmentally friendly mild steel (M-steel) corrosion inhibition using the artemisia stems aqueous extract (ASAEx) as an inhibitor in hydrochloric acid 1M. The standard extraction technique of hydrodistillation was used for producing the aqueous solutions of ASAEx. To assess the ratios of the chemical components, phytochemical screening was used to identify the stems of this plant. We used a variety of methods and techniques in our research on corrosion inhibition, including weight loss measures, surface analysis methods like XPS and SEM/EDS, electrochemical testing like PDP and EIS, as well as computational lead compound evaluation. Maximum inhibitory efficacy was achieved with 400mg/L ASAEx in 1M HCl at 303K, i.e. 90%. The PDP investigation verified the mixed-kind inhibitor status of the ASAEx extract. To describe the surface of M-steel, fitting and synthetic data were used to identify a constant phase element (CPE). SEM surface analysis was also used to detect the ASAEx effect on the surface of M-steel. X-ray photoelectron spectroscopy (XPS) analysis shows the presence of trace molecules of ASAEx on M-steel surface characterizing the bands in Maj-ASAEx (major compound of ASAEx). Density functional theory (DFT) and molecular dynamics simulations (MDs) were used in computational chemistry to clarify the adsorption mechanism and inhibitory impact.

Quinoline derivatives as corrosion inhibitors for mild steel in acid medium: Deeper insights from experimental, ab initio density functional theory modeling, and in silico ecotoxicity investigations

Two (E)-2-(((2-((7-chloroquinolin-4-yl)amino)ethyl)imino)methyl)-4-R-phenol Schiff bases derivatives CMN (R = NO2) and CMP (R = H) were successfully prepared. Then, CMN and CMP were evaluated as corrosion inhibitors for 1020 mild steel in 1.0 mol L–1 HCl using different methods. Gravimetric experiments have shown that CMN and CMP reach efficiencies of 80 and 91% at 1.45 mmol L–1. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) measurements have indicated the formation of a protective adsorbed film on the mild steel surface. Electrochemical Impedance Spectroscopy (EIS), Linear Polarization Resistance (LPR), Potentiodynamic Polarization (PP), and Electrochemical Frequency Modulation (EFM) have also shed some light on electrochemical behavior of compounds. These data have depicted better polarization resistance and lower corrosion current density in the presence of both organic molecules, also proving that the process is controlled by charge transfer and that CMN and CMP are mixed-type corrosion inhibitors. ab initio Density Functional Theory (DFT) investigated how two quinoline-based molecules (CMN and CMP) prevent corrosion on iron surfaces. Simulations revealed CMP bonds more strongly to iron than CMN, leading to better protection. Simulations also showed that these inhibitor molecules form a protective layer on the iron, slowing down the movement of corrosive substances. Environment risk assessment through QSAR-based models have indicated that the corrosion inhibitors do not have the potential to bioaccumulate in fish. Still, the acute and chronic toxicity values at the different trophic levels investigated call for attention for environmentally friendly structural optimization.

Exploring the efficacy of novel thiohydantoin derivatives with arylacetamide core as corrosion inhibitors for mild steel in acidic medium: insights from electrochemical analysis, comprehensive characterization, and quantum studies

Two new compounds of Thiohydantoin Derivatives N-(4-nitrophenyl)-2-((5-oxo-4,4-diphenyl-4,5-dihydro-1H-imidazole-2-yl)thio) acetamide and N-(4-fluorophenyl)-2-((5-oxo-4,4-diphenyl-4,5-dihydro-1H-imidazole-2-yl)thio) acetamide symbolized by NNOITAcetamide and N-FOITAcetamide respectively, were synthesized and characterized by NMR spectroscopy. Their effectiveness in inhibiting mild steel (M-S) corrosion in 1.0 M HCl at 298 K was investigated by potentiodynamic polarisation (PDP), electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), and surface examinations via energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM) as well as X-ray photoelectron spectroscopy (XPS). Experimental results have been supported by theoretical studies such as Density Functional Theory (DFT) calculations and Monte Carlo (MC) simulation studies. All findings indicate that inhibitors have a considerable impact on lowering the rate of corrosion, and that the efficiency of the inhibitors rises with the concentration of the inhibitor. Experimental results revealed that the efficacy of the new thiohydantoin derivatives with an arylacetamide nucleus increased with increasing inhibitor concentration, where their inhibition efficiencies reached maximum values of 92.1 %, 94.1 %, for NNOITAcetamide and N-FOITAcetamide, at 10−3 M, respectively. In addition, the icorr decreased with increasing concentration up to 85 µA cm−2 and 58 for NNOITAcetamide and N-FOITAcetamide respectively, with a blank as a reference of 1045 µA cm−2, while the efficacy reduces as the temperature increases. The activation and thermodynamic parameters indicated that these products act via chemical adsorption on the mild steel surface. Furthermore, the surface analysis (SEM, EDS, and XPS) confirmed the formation of a protective layer adsorbed on the mild steel surface. Polarization curves indicated that NNOITAcetamide and N-FOITAcetamide are mixed-type inhibitors. Moreover, the quantum chemical calculation well supports the experimental results.

Utilization of Extract from Bushcane (Costus Afer) as Green Corrosion Inhibitor for Mild Steel

Corrosion has adverse environmental consequences since it affects the manufacturing sector resulting in enormous economic loss. The corrosion characteristics and mechanism of mild in the solution of hydrochloric acid was studied. Extract of bush cane (Costus afer) was screened for physicochemical and phytochemical properties and utilized as corrosion inhibitor for mild steel, the process was optimized using Response Surface Methodology (RSM). The presence of OH, NH of alcohols, phenols, or substituents connected to aromatic rings, C=O for amides and ketones, C-N of aliphatic amines, and C=C of alkenes and nitriles were shown using Fourier Transform Infrared Spectroscopy (FTIR). The optimum condition was found by minimizing time, temperature, inhibitor concentration and corrosion rate while maximizing weight loss, and inhibitor efficiency. The results obtained revealed that the bush cane extract contain saponin, flavonoid, alkaloid and tannin, which suggests the potency of the extract as a good inhibitor as it contains a considerable amount of phytochemical with basic heteroatom. The statistical significance of the weight loss, corrosion rate and inhibitor efficiency were evaluated using the analysis of variance (ANOVA). it was observed that the regression was statistically significant at the F-value of 94.60, 25.87 and 4.72 respectively. P-value of > 0.0235, > 0.0001 and 0.0265 respectively. The optimum temperature, inhibitor concentration and contact time were found to be 27.9°C, 20.0% and 5 hours respectively at desirability value of 0.637. At this optimum condition, the weight loss was found to be 0.102%, corrosion rate was 1.583mg/cm<sup>2</sup>hr and inhibitor efficiency was 62.9%. From the results obtained in this experiment, It is concluded that the bushcane extract can be used as a corrosion inhibitor for the protection of mild steel.

Investigating the Effects of Urea-Zinc Sulfate-L Phenylalanine on the Corrosion Inhibition of Mild Steel Exposed to pH-4 Sulfuric Acid

Background: Corrosion of mild steel is a risk to material and stability. The practice of corrosion inhibitors is a cost-effective corrosion modification method for mild steel. Organic inhibitors rich in electrons might have an excellent ability to prevent corrosion. This study aims to assess the inhibitory effect of the mixture of Urea, Zinc Sulfate, and L-Phenylalanine, which has a high electron density Methods: MS corrosion was experimentally performed using H2SO4 at a pH of 4. Different gravimetric and conventional techniques, such as polarization, AC impedance AFM, UV, and fluorescence, were used to examine the studied data. Results: According to gravimetric measurements, this combination produced 93% effective inhibition. The findings of the impedance test proved that the mixture of inhibitors that was adsorbed on the metal surface effectively prevented corrosion. Conclusion: Likewise, according to the Polarization measurements, the inhibitor exhibits mixed-type performance with significant cathodic activity. UV, Fluorescence, and AFM findings showed that MS corrosion was suppressed because the inhibitor molecule adhered to the metal's surface and reduced.

Corrosion Inhibition Performance of Brachystegia eurycoma Leaf Extract on Mild Steel in Acid Media

The aim of this work is to investigate the corrosion inhibition of B. eurycoma leaves extract as a natural inhibitor for mild steel corrosion in 3 M H2SO4 solution. The corrosion inhibitory activity was analyzed by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The surface roughness and its properties through scanning electron microscopy (SEM). The obtained result from EIS divulges that the gradual increase in inhibitor concentration and time of immersion leads to progressive increase in inhibition efficiency. At the end of 8 hours immersion time and inhibitor concentration of 1000 mg/l the highest inhibition efficiency of (88%) was obtained. The potentiodynamic polarization results indicated that addition of B. eurycoma leaves extracts hindered the reaction rates of anodic and cathodic reactions thereby performing as mixed- type inhibitor. The corrosion current density also revealed that in the presence of B. eurycoma leaves extracts the value of corrosion density reduced considerably from 265.2 \(\mu\) A/cm2 for sample without inhibitor to 67.8 \(\mu\) A/cm2 for sample with inhibitor. Again, it was observed that in the presence B. eurycoma leaves extracts the mechanism of hydrogen (effervescence) evolution was unique whereas the anodic dissolution of iron mechanism experienced the impact of the inhibitor. SEM inspection revealed that the mild steel surface showed smoother and lower damage in the presence of inhibitor. Obvious correlations were found between corrosion inhibition efficiency and some quantum chemical parameters such as energy of highest occupied molecular orbital (EHOMO), energy of lowest unoccupied molecular orbital (ELUMO), energy gap (EL–H) and electronic density etc. The obtained results were further elucidated with frontier molecular orbital theory.

In-situ biosynthesized plant exudate gums‑silver nanocomposites as corrosion inhibitors for mild steel in hydrochloric acid medium

Natural gums due to availability, multifunctionality, and nontoxicity are multifaceted in application. In corrosion inhibition applications, their performance, in unmodified form is unsatisfactory because of high hydration rate, solubility issues, algal and microbial contamination, as well as thermal instability. This work attempts to enhance the inhibitive performance of Berlinia grandiflora (BEG) and cashew (CEG) exudate gums through various modification approaches. The potential of biogenic BEG and CEG gums−silver (Ag) nanocomposites (NCPs) for corrosion inhibition of mild steel in 1 M HCl is studied. The nanocomposites were characterized using the FTIR, UV–vis, and TEM techniques. The corrosion studies through the gravimetric and electrochemical (PDP, EIS, LPR, and EFM) analyses reveal moderate inhibition performance by the nanocomposites. Furthermore, the PDP results reveal that both inhibitors are mixed-type with maximum corrosion inhibition efficiencies (IEs) of 61.2 % and 54.2 % for BEG-Ag NCP and CEG-Ag NCP, respectively at an optimum concentration of 1.0 %. Modification of these inhibitors with iodide ion (KI) significantly increased the IE values to 90.1 % and 88.5 % for BEG-Ag NCP and CEG-Ag NCP at the same concentration. Surface observation of the uninhibited and inhibited steel samples using SEM/EDAX, 3D Surface profilometer, and AFM affirm that the modified nanocomposites are highly effective.