Optimal Inhibition Efficiency Research Articles

Comparative Investigation of the Corrosion Protection Efficacy of Spondias mombin Leaf Extracts on AA2024 Alloy and Low Carbon Steel in Acidic Medium

The anti-corrosive property of Spondias mombin (SM) leaves extract on low carbon steel (LCS) and aluminium alloy (AA2024) in 1M HCl solution was investigated using gravimetric and electrochemical methods. The results obtained from the weight loss experiment performed at various temperatures (30, 45, and 60 0C) show that the inhibition efficiency values decreased with temperature rise but increased as the inhibitor concentrations were increased. At 30 0C, optimum inhibition efficiency (IE) of 80.11% and 78.06% were obtained for LCS and AA2024 respectively. The potentiodynamic polarization (PDP) result reveal that an optimum IE values of 92.1% and 74.0% were respectively obtained for LCS and AA2024 while the electrochemical impedance spectroscopy (EIS) data show IE values of 91.5% and 74.5% for LCS and AA2024 respectively. In all cases, the values of inhibition efficiency obtained for LCS were greater than those obtained for AA2024. This implies that SM leaf extracts offers a better protective-layer on LCS surface compared to the AA2024 alloy in the acidic medium. The isotherm study reveal that Langmuir model best fitted the adsorption of the leaf extracts on LCS while Freundlich model best fitted the leaf extracts adsorption on AA2024 surface.

Green approach towards the corrosion suppression effect of carbon steel against an aggressive medium of 1 M HCl from peanut shells: Electrochemical examinations coupled with theoretical insights

The present work focuses on examining the corrosion inhibition activity of an aqueous green extract derived from peanut shell waste for carbon steel in 1 M HCl. The electrochemical tests evinced a notable inhibitory efficiency of the peanut shell extract (PSE). Total polyphenol and flavonoid content, as well as FT-IR analysis, were performed to explore the phytochemical abundance of the PSE, the results show the existence of polyphenol and flavonoid families in the aqueous extract of PSE. The electrochemical measurements PDP and EIS showed an optimum inhibition efficiency (IE) reaching 81% using 2 g/L of PSE at 293 K. The effect of temperature indicated that the mode of adsorption of PSE is physisorption. SEM-EDX analysis of the carbon steel surface texture was conducted to explore the PSE behavior at the surface. Based on Density Functional Theory (DFT) calculations at B3LYP/6-311 + G (d,p) level of theory, the anticorrosive effect of the main components of the aqueous green extract of peanut shells: Luteolin, (LTN) resveratrol (RVT) and p-hydroxybenzoic acid (HBA) was investigated, The HOMO and LUMO electron densities, as well as the molecular electrostatic potential maps, were used to identify the electron-rich and electron-poor regions. The most relevant global and local quantum chemical reactivity descriptors were also calculated and discussed. The results revealed that the inhibition efficiency of the investigated inhibitor molecules can be arranged as follows: RVT ≈ LTN ≫> HBA.

The study of expired pharmaceutical drugs as corrosion inhibitor for carbon steel in acidic media using the design of experiment

The performance of Bromhexine syrup has been investigated as a corrosion inhibitor for carbon steel (C-steel) in acid medium using the weight loss method and response surface methodology (RSM) of the design experiment. The effect of the concentration of the inhibitor, temperature and exposure time on inhibition efficiency and corrosion rate was studied. The experimental results revealed that expired drug is an effective inhibitor and its inhibition efficiency increases with the increasing concentration to attain a maximum of 97.23 % at 1.0 (v/v %) at 293 K. The thermodynamic parameters show that adsorption reaction on the C-steel surface is spontaneous and exothermic. Moreover, the energy barrier for the corrosion reaction increases in presence of the inhibitor. The individual and interactive effects of these three parameters were optimized for maximum response of inhibition efficiency using response surface methodology (RSM) within the experimental design. Second-order polynomial model was suggested to predict the inhibition efficiency as a function of three variables. The results from RSM gave a best second order polynomial model for the inhibition efficiencies (IE) with high R2= 0.998 and R2Adj= 0.997. Moreover, the value of Q2 greater than 0.9 indicating that the model used is excellent. This confirms a good agreement between experimental observed data and the predicted ones. The optimal inhibition efficiency (IE) obtained by RSM is 101.65 % for a concentration of 0.282 %, temperature of 20.87 °C and immersion time of 4h.

A computational and experimental investigation of novel synthesis fused pyrazolopyrimidine as zinc corrosion inhibitor in 1 M HNO3

Two compound derived from fused Pyrazolo-Triazolo-Pyrimidine (C1 and C2), have inhibitory action against corrosion of Zinc in 1 M HNO3 examined experimentally by electrochemical tests and theoretically by density functional theory (DFT). The findings demonstrate that zinc corrodes in acidic conditions with greater corrosion resistance than C1 and C2. Concentration and corrosion inhibition directly relate to one another. The two Pyrazolopyrimidine-derived compounds had optimum inhibition efficiency of 92.06 and 79.36% for C1 and C2, respectively, at 700 ppm. In accordance to the polarization curves, the antagonists feature a mixed but primarily anodic inhibitor and a Langmuir process. DFT computations validated the compounds apparent antagonistic response. SEM also show the development of a barrier on the zinc surface. In conclusion, these two antagonists, C1 and C2, are successful in avoiding zinc dissolution in HNO3.

1,4-Phenylenediamine-based Schiff bases as eco-friendly and efficient corrosion inhibitors for mild steel in HCl medium: Experimental and theoretical approaches

The application of Schiff bases as corrosion inhibitors is one of the economic, practical, and effective techniques to retard metal corrosion in aggressive environment. The continuous exploration of novel, lower-cost, more efficient, and eco-friendly corrosion inhibitors is an everlasting pursuit of excellence. In this study, two 1,4-phenylenediamine-based single Schiff base isomers, (E)-4-((pyridin-2-yl-methylene)amino)aniline (PMAA2) and (E)-4-((pyridin-3-ylmethylene)amino)aniline (PMAA3), were synthesized by one-step reaction. The corrosion inhibition mechanism and structure–activity relationship of PMAA2 and PMAA3 for mild steel in HCl solution were analyzed using electrochemical and weight loss experiments, morphology analysis, density functional theory (DFT) calculation, and molecular dynamic (MD) simulation. The results demonstrated that the corrosion inhibition efficiency of PMAA2 and PMAA3 exhibited an increasing trend with the elevation of inhibitor concentration while showing a slight decrease with the temperature rise. The optimal corrosion inhibition efficiency for 800 mg L−1 PMAA2 and PMAA3 in 1.0 mol L−1 HCl solution is 90.88 % and 91.78 % at 303 K respectively by using weight loss experiment. The electrochemical experiment results indicated that PMAA2 and PMAA3 are mixed-type corrosion inhibitors, with a preponderant control of anodic dissolution. Both the thermodynamics of adsorption and the kinetic of corrosion reaction were evaluated and discussed in detail. Their adsorption upon mild steel complies with Langmuir adsorption isotherm and is involved in phys- and chemisorption concurrently. The results from surfacemorphologyanalysis exhibited that a dense protective film on the surface of mild steel is formed through inhibitor adsorption, which results in changes in the hydrophilicity and hydrophobicity of the metal surface. The calculations of DFT and Fukui index also indicated that both the neutral and pronated species of PMAA2 and PMAA3 possess donor–acceptor interactions with the surface iron atoms through both forward and back-donations. Furthermore,MD simulations further revealed that the neutral molecules as neat-flat and parallel orientation are adsorbed strongly on the Fe (110) surface but the pronated species perform in bent fashion on the Fe (110) surface. Based on the experimental analysis and the theoretical calculation, a possible adsorption and corrosion inhibition mechanism was proposed rationally. These findings display good correlations between the experimental investigation and the theoretical computation and are of fundamental importance to understanding the adsorption and corrosion inhibition mechanisms of the inhibitors.

Evaluation of Morinda citrifolia extract as sustainable inhibitor for mild steel in saline environment

In this study, the Morinda citrifolia extract was evaluated as a sustainable inhibitor of mild steel in saline environments. The work aimed to determine the inhibition efficiency of new active material for metal corrosion inhibition. The powdered simplicia of M. citrifolia was extracted in the macerator for three days using a solvent daily. The functional group bonds of this extract were analyzed by Fourier Transform Infrared (FT-IR). The performance of M. citrifolia extracts was evaluated with potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques using a three-electrode cell system. The surface morphology of mild steel was pictured by Field effect scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray spectroscopy (EDX). Potentiodynamic polarization results show decreasing corrosion current (Icorr) with the presence of an extract of M. citrifolia. Furthermore, resistance capacity transfer (Rct) increases with the addition of M. citrifolia extract. The optimum inhibition efficiency (%IE) was achieved at 300 mg L−1 concentrations with 85.10% efficiency by using the PDP technique. The mild steel morphology in the addition of M. citrifolia extracts is smoother than the surface without adding extracts. The increase in corrosion inhibition was associated with the molecule adsorption from the active compounds into the steel surface. The study results confirmed that M. citrifolia is a potential biomaterial engineering for corrosion inhibitors on mild steel in a saline environment.

PH‐Responsive Chitosan Microspheres Loaded with Gemini Imidazolium‐Based Ionic Liquids as Smart Corrosion Inhibitors for N80 Steel in Hydrochloric Acid Solution

Chitosan microspheres (CSM) loaded with synthesized Gemini imidazolium‐based ionic liquids ([C2(Bim)2]Cl2@CSM and [C6(Bim)2]Br2@CSM) are constructed as smart corrosion inhibitors to protect N80 steel in hydrochloric acid solution. The optimal inhibition efficiency of [C2(Bim)2]Cl2 and [C6(Bim)2]Br2 at 300 mg L−1 reaches 94.68% and 95.96%, respectively, indicating mixed‐type inhibition behavior. On this basis, the prepared [C2(Bim)2]Cl2@CSM and [C6(Bim)2]Br2@CSM can proactively identify corrosive environments and protect the metal. The microspheres are pH‐responsive owing to the presence of Schiff‐base C═N bonds and the loaded inhibitors can be released rapidly in acidic environment. Released inhibitors are delivered to corroded sites and synergistically interact with decomposed microspheres for enhanced corrosion inhibition effect.

Evaluation of adsorption and corrosion inhibition properties of Solanum Macrocarpon leaves extract on mild steel in sulphuric acid solutions

Corrosion of mild steel (MS) in industries has become a menace that has led to the use of organic green inhibitors from plant origin, which is seen as a cheap, eco-friendly substitute for inorganic inhibitors. This work employed Solanum macrocarpon (SM) methanol leaf extract as a green inhibitor using a gravimetric method at 303–323 K, respectively. The phytochemical screening was done using standard methods to identify the phytochemical compounds in the leave extract. The Fourier transform infrared (FTIR) analysis was also done to elucidate the functional groups that contain heteroatoms responsible for the inhibition efficiency. The effectiveness of the inhibition efficiency increased with concentration and decreased with rising temperature. The results demonstrated that Solanum macrocarpon leaf methanol extract is an effective mild steel corrosion inhibitor in 0.5 M H2SO4. 95% optimum inhibition efficiency (I.E) was observed at 0.5% w/v concentration for 303 K. The inhibition potential was attributed to the phytochemical compounds in the leaf extract, which contain polar functional groups and hetero-atoms in their structures. The Ea\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${E}_{a}$$\\end{document} and ΔGads\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta {G}_{ads}$$\\end{document} showed that the adsorption mechanism followed physisorption. The results showed the potential use of SM methanol extract as a corrosion inhibitor in mild steel, which can decrease corrosion in industries.

DFT-details & atomic-scale MC/MD simulations and experimental exploration of the Silybum extract bio-molecules effectiveness in mitigating aggressive effects of simulated corrosive concrete pore solutions

The growing emphasis on sustainability and environmental awareness is paramount today. Corrosion control, often achieved through inhibitors, is a prominent approach, with plant extracts being favored for their accessibility and ease of extraction. Yet, their efficacy in alkaline environments, common in construction materials like cement and concrete, remains constrained. This study evaluates the potential of Silybum extract as a corrosion inhibitor within a simulated chloride-contaminated concrete setting, employing electrochemical and surface analyses to scrutinize the inhibitory characteristics and surface chemistry of the treated samples. Following the analysis of concentrations at 0.5%, 1%, and 2% Silybum extract in the simulated concrete solution, the optimal inhibition efficiency of 96.5% was obtained based on polarization measurements. The electrochemical impedance spectroscopy (EIS) confirmed that the log of impedance at low-frequencies (log|Z|10mHz) for the inhibited sample had a noticeable increment compared to the blank sample, rising from 4.60 to 5.13 after 48 h of exposure. The use of Silybum extract resulted in a remarkable 89% increase in total resistance after 5 h of immersion, as compared to the blank basic solution. Silybum exhibited a protective effect on metal substrates through three key mechanisms: forming a passive surface film via electron donation, inhibiting corrosion reactions through surface adsorption, and reducing corrosive species diffusion via physical surface coverage by heavy components. These mechanisms were supported by various surface studies which revealed the formation of a protective layer instead of corrosion products originating from Silybum components. Also, the interaction of cations in the basic solution with Silybum components and the adsorption of the obtained complex on the metal surface was demonstrated via computer modeling calculations. Theoretical studies revealed negative adsorption energies for the complexes (−1129.83 kcal/mol energy in molecular dynamics (MD) simulation for the [Ca(Silychristin)3]+2 complex), confirming their strong chemical affinity for interfacial attachment.

Insight into the Corrosion Inhibition Mechanism of Sodium Silicate on the Magnesium Alloy Surface: Experimental and Theoretical Calculations.

The corrosion inhibition mechanism of sodium silicate (SS) for WE43 magnesium alloy in NaCl solution was investigated by in situ observation, electron probe microanalysis (EPMA), electrochemical test, and theoretical calculations. In situ observation showed that local corrosion was markedly inhibited after the addition of the SS inhibitor. Electrochemical data revealed that a protective layer was formed on the metal/solution interface and an optimum inhibition efficiency of 98.3% in the case of 2.5 g/L SS. A uniform magnesium silicate layer with a thickness of ∼2 μm formed on the uncorroded area was confirmed. Quantum chemical calculations revealed that SiO32- could absorb on the MgO (1 0 0) surface in a parallel orientation through the coordinate bonds between the O and Mg atoms. The distances of Mg-O bonds are 2.052 and 2.249 Å, suggesting that they are coordinated. The adsorption/interaction mechanisms of SiO32- were also analyzed through charge density distribution and atomic densities. Molecular dynamics simulations further confirmed that a uniform SiO32- layer was absorbed on the MgO surface. In the local corroded area, free SiO32- would react with Mg2+ and OH- produced by corrosion to form the insoluble magnesium silicate compound, which hindered the spread of corrosion.

Assessment of corrosion inhibition performance of olive leaf extract mediated chitosan–Ag nanocomposites and influence of KI addition for X60 steel in acid solution

Chitosan–silver (CHT–Ag) nanocomposite (NCP) containing various dosages of chitosan (0.5, 1.0 and 2.0 g) was synthesized in-situ using olive leaf extract (OLE) as reducing and capping agent. The OLE mediated CHT–Ag NCP was characterized using UV–vis spectrometer, attenuated total reflectance-infrared spectroscopy (ATR-IR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM) techniques. The prepared NCP was assessed as corrosion inhibitor for X60 steel in 5% HCl solution using weight loss (WL) and electrochemical (electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and potentiodynamic polarization (PDP)) methods complemented by surface analysis of the corroded carbon steel (CS) without and with the NCPs utilizing scanning electron microscopy (SEM)/EDS, 3D optical profilometer and atomic force microscopy (AFM). The influence of adding KI on the corrosion inhibition performance of NCPs was investigated as well. TEM results indicate that CHT–Ag nanocomposites are polydisperse and spherical in shape with sizes in the range of 3.7–18.1 nm. The crystalline nature of Ag nanoparticles in the nanocomposites was confirmed by XRD and TEM examination. The prepared NCPs function as effective inhibitors for X60 CS corrosion in the acidic environment. Corrosion inhibition effect was observed to increase with rise in the NCPs concentration with the optimum inhibition efficiency (IE) obtained at the maximum dosage of 0.5% studied. The order of corrosion inhibition performance followed the trend CHT2.0 – Ag > CHT1.0 – Ag > CHT0.5 – Ag NCP. Also, IE was found to decrease with rise in temperature. The PDP data indicates that the NCPs alone and in combination with KI, reduced X60 CS corrosion via the mechanism of active site blocking effect. The addition of KI to the NCPs improves IE but not due to synergism. The surface assessment data confirms the establishment of a protective layer due to NCPs adsorption on the X60 CS surface.

Anti-corrosive and anti-microbial activity of MTMI on CRCA metal

The present study was intended to demonstrate the synthesis, and characterization of 1-(3-methoxyphenyl)-N-(4H-1,2,4-triazol-4-yl)methan-imine(MTMI) as an inhibitor for the corrosion on CRCA in 1 M HCl. In addition to this, molecular docking, and biological activity was carried out. MTMI formation was confirmed by FTIR and NMR spectroscopic studies. The corrosion inhibition effect was studied by weight loss, potentiodynamic polarization (PDP) measurements, and electrochemical impedance spectroscopy (EIS) techniques. The conditions for optimum inhibition efficiency were established by varying the concentration of the inhibitor and temperature by weight loss method. Kinetic and thermodynamic parameters were calculated and discussed. Results were fitted into various adsorption isotherm models. The adsorption of MTMI on CRCA was confirmed by scanning electron microscopy (SEM). Adsorption obeyed the Langmuir isotherm model and followed physical adsorption. Increasing inhibitor concentration led to a significant reduction in the corrosion rate of mild steel, with an inhibitor efficiency value above 93%. A molecular docking study showed the binding capacity of the protein endo-polygalacturonase (1HG8) and the activity of polygalacturonase enzyme on MTMI was measured.

Adsorptive investigation of the anticorrosion properties of natural chrysin on carbon steel in acid–chloride system: combined theoretical and experimental approach

Purpose Owing to the toxicity, biodegradability, and cost of most corrosion inhibitors, research attention is now focused on the development of environmentally benign, biodegradable, cheap, and efficient options. In consideration of these facts, chrysin, a phytocompound of Populus tomentosa (Chinese white poplar) has been isolated and investigated for its anticorrosion abilities on carbon steel in a mixed acid and chloride system. This highlights the main purpose of the study. Design/methodology/approach Chrysin was isolated from Populus tomentosa using column chromatography and characterized using Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance Spectroscopy. The investigations are outlined based on theory (Fukui indices, condensed density functional theory and molecular dynamic simulation) and experiments (electrochemical, gravimetry and surface morphology examinations). Findings Theoretical evaluations permitted the description of the adsorption characteristics, and molecular interactions and orientations of chrysin on Fe substrate. The interaction energy for protonated and neutral chrysin on Fe (110) were −149.10 kcal/mol and −143.28 kcal/mol, respectively. Moreover, experimental investigations showed that chrysin is a potent mixed-type corrosion inhibitor for steel, whose effectiveness depends on its surrounding temperature and concentration. The optimum inhibition efficiency of 78.7% after 24 h for 1 g/L chrysin at 298 K indicates that the performance of chrysin, as a pure compound, compares favorably with other phytocompounds and plant extracts investigated under similar conditions. However, the inhibition efficiency decreased to 62.5% and 51.8% at 318 K after 48 h and 72 h, respectively. Originality/value The novelty of this study relies on the usage of a pure compound in corrosion suppression investigation, thus eliminating the unknown influences obtainable by the presence of multi-phytocompounds in plant extracts, thereby advancing the commercialization of bio-based corrosion inhibitors.

Synthesis of a dibenzimidazole compound and its corrosion inhibition behavior on AZ91D Mg alloy in 3.5 wt.% NaCl solution

In this work, a low-cost and easily purified small molecule dibenzimidazole compound (BBI) was synthesized by the condensation of o-phenylenediamine and malonic acid. BBI was a new corrosion inhibitor for magnesium alloys and its corrosion inhibition behavior on AZ91D magnesium alloy was studied by electrochemical measurements, surface analysis and theoretical calculations in 3.5 wt.% NaCl solution at 30 °C. The adsorption behavior and corrosion inhibition mechanism of BBI molecules were discussed. It was found that BBI exhibited excellent inhibition effect on the corrosion of magnesium alloy. When BBI concentration was 0.25 g/L, the optimal corrosion inhibition efficiency was 86.2%. The adsorption of BBI molecule obeyed Langmuir adsorption on the surface of magnesium alloy, and one side of BBI molecule was adsorbed on the surface of magnesium alloy in parallel through physical and chemical mixed adsorption.

Inhibitive effect of anionic/zwitterionic hybrid surfactants on the self-corrosion of anode for alkaline Al-air battery

Surfactants have been increasingly used as corrosion inhibitors in recent years. The zwitterionic surfactants can keep their amphoteric characteristics within a wide range of pH and temperature. In this research work，the self-corrosion of Al anode in alkaline electrolyte for Al-air battery is suppressed by adding a hybrid corrosion inhibitor consisting of dodecyl dimethyl betaine (DDBT) and sodium dodecylbenzene sulfonate (SDBS). The hybrid surfactant behaves as an anodic inhibitor. The results show that the optimum inhibition efficiency is 91.27 % for 1 × 10−3 M DDBT + 4 × 10−3 M SDBS. The combination of DDBT and SDBS decreases the corrosion rate of AA5052 alloy in sodium hydroxide electrolyte. The hydrophilic heads of DDBT and SDBS can adsorb on surface. The long alkyl chains in surfactant bring an increase in hydrophobicity. The hybrid surfactants have the electrostatic interaction and hydrophobic interaction, which improving the inhibition effect for the hydrogen evolution reaction. In general, the mixture of anionic and zwitterionic surfactants can provide the potential for better inhibition performance and significance for practical application.

Experimental and Theoretical Studies of the Corrosion Inhibition Performance of Fatty Acid-based Ionic Liquids for Mild Steel in 1 M HCl: Effects of the Varied Alkyl Chain Length in the Anionic Group

Five fatty acid-based ionic liquids (FAILs) with various anionic alkyl chain lengths are synthesized, namely methyltrioctylammonium butyrate ([N8881][C4:0]), methyltrioctylammonium caproate ([N8881][C6:0]), methyltrioctylammonium octanoate ([N8881][C8:0]), methyltrioctylammonium laurate ([N8881][C12:0]), and methyltrioctylammonium palmitate ([N8881][C16:0]), to investigate the potential effects of anionic alkyl chains on their corrosion inhibition property for mild steel in 1 M HCl solution via X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle measurements, electrochemical measurements, and weight loss measurements. The results reflect that the FAIL inhibitor can adsorb on the surface of mild steel to form a protective film and effectively inhibit the corrosion. [N8881][C8:0] exhibits the optimal inhibition efficiency (96.94%) in comparison to [N8881][C4:0] (80.73%), [N8881][C6:0] (89.34%), [N8881][C12:0] (90.69%), and [N8881][C16:0] (74.42%). It is speculated that the varied anionic alkyl chain length may change the intensity of the protective film to affect the inhibition efficiency. The in-depth analysis by molecular dynamic simulation confirms that [N8881][C8:0] with the same anionic and cationic alkyl chain lengths shows the most ordered and compact film on the mild steel surface. The present study focuses on the effects of the anionic alkyl chain on the corrosion inhibition performance and provides novel insights into the design and development of effective and eco-friendly ionic liquids as corrosion inhibitors.

Corrosion Inhibition Data and Statistical Analysis of the Performance of Rosemary Oil Extract on High Carbon Steel in Dilute Electrolyte Solutions

Application of plant extracts for the corrosion protection of engineering materials is an ongoing research to replace the conventional toxic, costly and unsustainable chemical derivatives. Data on the corrosion inhibition performance of rosemary oil extracts on high carbon steel in 0.5 M C6H8O7, 0.5 M H2SO4 and 3.5 wt.% NaCl solution was studied and the inhibition efficiency data statistically analysed. The oil extract performed poorly in C6H8O7 solution with optimal inhibition efficiency of 49.21% at 1.5% extract concentration. However, the extract performed effectively in H2SO4 and NaCl solution with optimal inhibition efficiency of 78.45% at 2.5% extract concentration and 97.87% at 1.5% extract concentration. Inhibition efficiency varied significantly with exposure time and concentration. The oil extract exhibited chemisorption type adsorption mechanism in all the solutions in consonance with Langmuir, Frumkin and Freundlich adsorption isotherms. Statistical data on standard deviation showed the variation of extract inhibition efficiency with respect to mean inhibition value and exposure time was relatively significant in C6H8O7 solution due to instability of inhibitor molecules, compared to the relatively low values obtained in H2SO4 and NaCl solution. Data from numerical variation showed extract concentration is the dominant statistically relevant inducing inhibition performance of rosemary oil extract in C6H8O7 and NaCl solution with statistical relevance factor of 63.40% and 70.36% compared to the corresponding values obtained in H2SO4 solution were extract concentration and exposure time were statistically relevant. Data showed 30%, 19% and 90% of inhibition efficiency data in C6H8O7, H2SO4 and NaCl solution are above 70% inhibition value at margin of error of +0.09, +0.077 and +0.059.

Pemanfaatan Ekstrak Biji Feun Kase (Thevetia peruviana) sebagai Inhibitor Korosi Logam Seng dalam Media HCl

Feun Kase seed extract can be used as a corrosion inhibitor on zinc metal in HCl solution. This study aims to determine the secondary metabolites contained in Feun Kase seed extract, inhibition efficiency and corrosion rate, and surface morphology of zinc metal in the inhibition process using Feun Kase seed extract in HCl media. Feun Kase seed extract was obtained by maceration extraction using methanol. In the corrosion inhibition test, the concentration and temperature variations were carried out to determine the effect on the inhibition efficiency and the corrosion rate per year. The results showed that the methanol extract of Feun Kase seeds contained secondary metabolites of alkaloids, flavonoids and saponins. The optimum inhibition efficiency was obtained at an inhibitor concentration of 30 ppm of 82.70% with a corrosion rate of 5.80 mm/year and at a temperature of 35ºC of 75.84% with a corrosion rate of 7.28 mm/year in the test of increasing the temperature of the corrosion medium. The morphological analysis of the zinc plate using the SEM instrument showed that the zinc plate without surface treatment (not immersed in HCl media) was still smooth. This is indicated by the surface of the zinc plate which is still clearly visible because it has not been affected by the corrosion medium. The zinc plate when immersed in HCl media, is damaged which is indicated by the presence of pores or holes. Zinc plate when added with Feun Kase seed extract in HCl media, the zinc surface was damaged but the damage was not as prominent as in HCl media without using an inhibitor.

Preventing re-emission of malodorous dimethylamine via tunable nonradical oxidation catalyzed by waste mask-derived carbocatalyst

The re-emission of dimethylamine (DMA), as a famous malodorous volatile organic compound (VOC), exhausted from various industries receives emerging concerns. Herein, a metal-free carbocatalyst derived from waste masks was developed to inhibit DMA re-emission via activating peroxymonosulfate (PMS). The optimal inhibition efficiency was around 99%, 85-fold higher than that without any carbocatalysts and PMS. Such enhancement was ascribed to the rapid conversion of DMA (kobs = 0.67 min−1, 4 min) into non-volatile and lower toxic substances (NO3−, NO2− and aliphatic acids) by electron transfer and singlet oxygenation. Experiments combined with correlation analysis and theoretical calculations unveiled that the intensified graphitization degree promoted the electron migration from DMA to the carbocatalyst/PMS* complex due to the enhanced electron transfer rate and elevated redox potential, and PMS preferentially absorbed on the electron-rich C=O and deprotonated COO− groups rather than C-OH and COOH of carbocatalyst and then released SO5− for the generation of 1O2. Based on the theory, tuning the graphitization degree and amount of C=O and COO− groups via a simple annealing strategy triggered a shift from singlet oxygenation to predominantly direct electron transfer pathway, thus achieving optimal suppression efficiency of DMA re-emission. Finally, electrical energy per order (EE/O) analysis demonstrated our technology had a relatively low EE/O value (3.56 kWh/m3) and cost (0.47 $/m3). Considering the high efficiency and low cost of carbocatalytic PMS system endowed with clear mechanism and controllable properties, this work, therefore, pioneers an unparalleled approach for the industrial governance of effluvial VOCs treatment, and provides new insights into the tunable nonradical oxidation mechanism of carbocatalytic PMS activation.

Synthesized of Novel Imidazole-derived Schiff Base as a Corrosion Inhibitor of Carbon Steel in Acidic Medium Supported by Electrochemical and DFT Studies

In this work, a new synthesized imidazole derivative, namely (N,N'E,N,N'E)-N,N'-(thiophene-2,5-diylbis(methanylylidene))bis(1H-benzo[d]imidazol-2-amine) which is donated as (SJ1), was tested as inhibitor in controlling the corrosion of carbon steel in 0.1 M hydrochloric acid solution by using open circuit potential (OCP), potentiodynamic polarization (PDP), at four different temperatures (293, 303, 313 and 323 K) and various of SJ1 concentrations. Furthermore, the surface morphology was investigated using both the Atomic force microscopy (AFM) and Scanning Electron Microscope (SEM), respectively. SJ1 was synthesized and characterized via using the Uv-vis, mass spectroscopy, 1H-NMR and 13C-NMR spectroscopy, and the element analysis CHN. From the experimental results shown that SJ1 can consider as an excellent corrosion inhibitor for carbon steel in acidic solution. The inhibition efficiency is increased with increasing the inhibitor concentration but is decreased with the increases of temperature, and the optimum inhibition efficiency by 5x10-4M of SJ1 is 96%. The adsorption behavior of the a new synthesized inhibitor on to the surface of the carbon steel was investigated and found is obeyed the Langmuir adsorption isotherm. DFT results were employed to study the electronic properties of SJ1.