Increase In Inhibition Efficiency Research Articles

Study the Effect of “Di-dodecyl amine” as a Corrosion Inhibitor for Carbon Steel in HCl Medium

Numerous organic compounds have been investigated for their potential to reduce corrosion under various circumstances. This study investigated the effects of di-dodecyl amine, an organic chemical, on carbon steel metal corrosion at different temperatures while HCl acid was present. The examination was carried out using accepted methods for polarization, weight loss, and corrosion process testing. The obtained findings demonstrated that the corrosion rate reduces with increasing inhibitor concentration, leading to increased inhibition efficiency. Furthermore, as shown in the weight loss technique, the corrosion rate lowers with increasing surface coverage with organic inhibitor at 313 °C. In the anodic and cathodic polarization methods, as well as in the inhibition efficiency, it is observed to see the cathodic and anodic curves through which the occurrence of the potential and corrosion current is known. The current and corrosion potential decreases with increasing inhibitor concentration. The amines and methyl motiveless in this inhibitor's composition give it their efficacy since they may coat the metal surface and stop corrosion

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.

Corrosion Inhibition by Musa paradisia ca Peel Extract for SS 304 in 1 M Hydrochloric Acid Solution

Objectives: To study the corrosion inhibition of Musa paradisiaca peel (MPP) extract for stainless steel (SS) 304. Method: The corrosion rate of stainless steel was studied by weight loss measurements in a 1 M hydrochloric acid solution at different concentrations of MPP inhibitor and at various temperatures, e.g., 298 K, 303 K, and 308 K. Scanning electron microscopy (SEM) was used to study the morphology of the films created on the stainless steel surface in various immersion media at various immersion times. Both potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) examined inhibition efficiency. Langmuir adsorption isotherm studied inhibitor surface adsorption SS 304. Findings: The corrosion rate and inhibition efficiency depend on the concentration of the inhibitor and the temperature. When there is an increase in the concentration of the inhibitor, inhibition efficiency increases, e.g., at 50 mg/l concentration, 77% inhibition efficiency, and at 200 mg/l concentration, 87% inhibition efficiency at 298 K. When temperature increases, inhibition efficiency decreases, e.g., at 200 mg/l concentration, 87% at 298 K, 85% at 303 K, and 83% at 308 K. Novelty: This article provides an eco-friendly corrosion inhibitor for stainless steel 304. Musa paradisiaca peel extract inhibitor was previously used for iron, mild steel, and carbon steel but was not used for stainless steel 304 in 1 M HCl. Keywords: Corrosion, Stailess stell, Inhibitor, Acid

Advancing steel protection with Ceria@Talc-8-hydroxyquinoline modified Polyurethane coatings

This research delves into a hybrid framework involving the synthesis of composite particles combining ceria-modified talc (CeO2@Talc) through a chemical precipitation method. The hybrid particles were then loaded with 8-Hydroxyquinoline (8-HQ) to serve as a corrosion inhibitor. The resulting CeO2@Talc-8HQ hybrid particles were subsequently incorporated into a polyurethane (PU) matrix and deposited on steel substrate to investigate and assess their barrier properties. The synthesized particles and developed coatings were characterized in detail utilizing various techniques. The Brunauer–Emmett–Teller (BET) results showed a decrease in the specific surface area and pore volume of modified particles as compared to that of pristine talc. These results demonstrated the successful loading and modification of the particles. The thermal gravimetric analysis (TGA) results showed excellent thermal behavior with only 2 % weight loss beyond 900 °C of the modified CeO2@Talc particles. The potentiodynamic polarization results represented 76.28 % increase in the corrosion inhibition efficiency in the presence of the modified particles. When these modified hybrid particles were reinforced (1.wt%) into the PU matrix, they exhibited an impressive impedance modulus of 56.14 GΩ.cm2 at 0.01 Hz, outperforming blank PU coatings which showed 0.002 GΩ.cm2 after four weeks of immersion in a 3.5 wt% saline solution. The incorporation of modified particles into the PU matrix results in significant improvements in various observed parameters such as the lowest break point frequency, damage index, and intersection frequency of the bode plot. These positive outcomes indicated that the modified coatings efficiently blocked the micropores of the PU matrix, preventing the diffusion of electrolytes into the coatings. Overall, this study not only introduced a novel structural design for superior corrosion mitigation but also demonstrated promising potential of corrosion protection for industrial applications.

Dramatic improvement in corrosion inhibition effect of carboxymethyl cellulose by modified with levodopa: Experimental study and first-principles calculations

Cellulose, as a kind of renewable natural polymer, has great potential as green corrosion inhibitor. However, the low inhibition effect is the obstacle to its practical application. Herein we developed a high efficiency green cellulose derivative corrosion inhibitor, levodopa-carboxymethyl cellulose (LDCMC), by modifying carboxymethyl cellulose (CMC) with levodopa (LD) through a simple amidation reaction. The inhibition effect of CMC for mild steel in HCl medium is dramatically improved with an increase in inhibition efficiency from 56.98% of CMC to 97.27% of LDCMC. The intrinsic nature of the dramatically improved inhibition effect is in-depth unraveled by first-principles calculations based on density functional theory (DFT). CMC and LDCMC can adsorb on the mild steel surface through -OH, -COOH and LD fragment by forming the covalent bonds with steel surface. Benefiting from the additional strong adsorption of the benzene ring in LD fragment, the introduction of LD can significantly enhance the adsorption capacity of LDCMC, which is the intrinsic nature of the dramatical improvement in the inhibition effect of LDCMC.

Arachis hypogaea’s concentration effect on AISI 1020 carbon steel for corrosion protection

The effects of inhibitor concentration on the corrosion rate and inhibition efficiency of AISI 1020 steel in an acidic and alkaline environment were investigated by means of weight loss measurement at an interval of 7 days and 14 days. To carry out this investigation, the Arachis hypogaea hull was extracted and concentrated in various weight percentages. The inhibition efficiency increased with the increased concentrations of AISI 1020 steel that were immersed in acidic and alkaline solution in the absence and presence of varying inhibitor concentrations of Arachis hypogaea hull extracts. The corrosion behavior, including the corrosion rate, is meticulously characterized through the corrosion rate analysis. The results showed that there is an increase in inhibition efficiency with an increase in inhibitor concentration and that there is a decrease in inhibition efficiency with an increase in immersion time. The organic inhibitor (Arachis hypogaea hull) produced the best inhibition efficiency of 96.4% at a 30% concentration. From the result obtained, Arachis hypogaea hull extracts revealed that it is best suited for inhibition of corrosion of mild steel in both acidic and alkaline environments. The goal of this research paper is to develop a comprehensive understanding of the corrosion inhibition and adsorption mechanisms associated with the implementation of the Arachis hypogaea hull as a natural corrosion inhibitor.

Pyracantha fortuneana alcohol extracts as biodegradable corrosion inhibitors for copper in H2SO4 media

Compared with traditional copper corrosion inhibitors, Pyracantha fortuneana alcohol extracts are derived from natural plants, will not cause environmental pollution after use, and are in line with the concepts of green chemistry and sustainable development. In this study, Pyracantha fortuneana alcohol extracts (PFAE) were obtained by ethanol soaking extraction method. PFAE, a novel degradable green corrosion inhibitor, has been investigated by experiments and theoretical calculations for its anti-corrosion performance of copper in H2SO4 solution. Electrochemical experiments have demonstrated a pronounced increase in corrosion inhibition efficiency (η) as the concentration of PFAE rises. At a PFAE concentration of 600 mg/L, the inhibition efficiency can exceed 95 %. Additionally, the electrochemical method was used to investigate how the effect of soaked time on its anti-corrosion performance. After 4 h of immersion in a H2SO4 solution containing PFAE, the copper could still maintain more than 80 % of the anti-corrosion performance. The results of surface morphology analysis demonstrate that after adding PFAE, the roughness of the copper sample is significantly reduced. This provides intuitively evidence that PFAE can indeed proficiently inhibit copper corrosion within a sulfuric acid solution. According to the study of the adsorption model, it was found that the adsorption behavior of PFAE onto the copper surface adheres to the Langmuir monolayer adsorption model. Moreover, the findings indicate the coexistence of both physical and chemical adsorption mechanisms. The findings of molecular dynamics simulations (MD) and quantum chemistry (QC) calculations indicate that the six active components of PFAE can display strong anti-corrosion capability.

The inhibition of 3H-2- Methyl-1,2,4- Triazepino[2,3-a] Benzimidazole-4(5h)-one (MTB) on corrosion of mild steel in 1 M HCl solutions; Theatrical and experimental study

The inhibitive action of a new Benzimidazole derivation, 3H-2-Methyl-1,2,4-Triazepino [2,3-a] Benzimidazole-4 (5h)-one (MTB), for the corrosion of mild steel in one molar hydrochloric acid solution was investigated. Corrosion tests has been conducted using weight loss measurement electrochemical method and scanning electron microscopy associated with energy dispersion spectrometer (SEM/EDS). The results showed increasing inhibition efficiency with increasing the inhibitor concentration and reach to 98% at 1×10-2 M. The thermal studies indicated that the newly synthesized MTB inhibited the corrosion of mild steel by its adsorbing on the specimen surface via both physisorption and chemisorption mechanism. The adsorption process of MTB on the mild steel surface obeys Langmuir adsorption isotherm and act as mix-type inhibitor. The analysis of surface morphology confirmed the thermal results by showing the MTB molecules on the mild steel surface. Various DFT parameter like HOMO and LUMO energy, gab energy (∆E), electronegativity (χ), softness (�, global hardness (η) were derived for MTB molecules and correlated with experimental results. Keywords: Surface morphology, Thermal study, Corrosion, Inhibitor, Polarization, Mild Steel, Isotherm, Benzimidazole, Quantum chemical, DFT Calculation.

IONIC RADII OF HALIDE IONS AND ITS CORROSION INHIBITORY ENHANCEMENT ON SIDA ACUTA.

Corrosion Inhibitory efficiencies of Sida acuta leaf extracts in combination with halide ions (F-, Cl-, Br- and I-) as an enhancement on aluminum corrosion in H2SO4 was studied at room temperature (25oC) under varying acid concentrations of 0.05M, 0.1M and 0.5M using weight loss method. From the results obtained, Sida acuta acts as a good inhibitor for aluminum corrosion in acidic environment and it's inhibitory efficiencies increases with time of exposure. Based on the experimental results, the corrosion rate increases rapidly in the blank with a weight loss accelerating from 0.009g to 0.038g but with the introduction of plant extract, weight loss got reduced from 0.007g to 0.027g as well as having inhibition efficiency of 36% to 12% as the concentration of the acid was increased from 0.05M to 0.5M over the time series of 24 h to 96 h.. However, the inhibitory efficiency of Sida acuta in H2SO4 medium was further improved when halide ions were introduced. The weight loss of NaI moved from 0.002g to 0.011g and hence had the highest inhibition efficiency among the halide ions from 78% to 50% , NaBr showed a weight loss ranging from from 0.003g to 0.022g as well as having inhibition efficiency of 67% to 42% while NaCl showed a weight loss of 0.005g to 0.023g as well as having inhibition efficiency of 55% to 32% as the acid concentration was increased from 0.005M to 0.5M over the time exposure of 24 h to 96 h.. Nevertheless, the weight loss of NaF increases rapidly from 0.020g to 0.050g even more than the blank under the same reaction conditions and hence does not show inhibition efficiency. Therefore, the increase in inhibition efficiency (%I) and surface coverage (?) in the presence of the halides was found to be in a special sequence. . This synergistic effect increased according to the following pattern Cl- < Br -< I- suggesting a possible role by ionic radii in the corrosion inhibitory process which also increase in the order, F/F – ( 0.072/0.133nm), Cl/ Cl- (0.099/0.181nm) < Br/ Br - ( 0.114/ 0.195nm) < I/ I- ( 0.133/0.216 nm) . Fluoride ion does not show any inhibitory enhancement on Sida acuta owing to its least ionic radius..

IONIC RADII OF HALIDE IONS AND ITS CORROSION INHIBITORY ENHANCEMENT ON SIDA ACUTA.

Corrosion Inhibitory efficiencies of Sida acuta leaf extracts in combination with halide ions (F-, Cl-, Br- and I-) as an enhancement on aluminum corrosion in H2SO4 was studied at room temperature (25oC) under varying acid concentrations of 0.05M, 0.1M and 0.5M using weight loss method. From the results obtained, Sida acuta acts as a good inhibitor for aluminum corrosion in acidic environment and it's inhibitory efficiencies increases with time of exposure. Based on the experimental results, the corrosion rate increases rapidly in the blank with a weight loss accelerating from 0.009g to 0.038g but with the introduction of plant extract, weight loss got reduced from 0.007g to 0.027g as well as having inhibition efficiency of 36% to 12% as the concentration of the acid was increased from 0.05M to 0.5M over the time series of 24 h to 96 h.. However, the inhibitory efficiency of Sida acuta in H2SO4 medium was further improved when halide ions were introduced. The weight loss of NaI moved from 0.002g to 0.011g and hence had the highest inhibition efficiency among the halide ions from 78% to 50% , NaBr showed a weight loss ranging from from 0.003g to 0.022g as well as having inhibition efficiency of 67% to 42% while NaCl showed a weight loss of 0.005g to 0.023g as well as having inhibition efficiency of 55% to 32% as the acid concentration was increased from 0.005M to 0.5M over the time exposure of 24 h to 96 h.. Nevertheless, the weight loss of NaF increases rapidly from 0.020g to 0.050g even more than the blank under the same reaction conditions and hence does not show inhibition efficiency. Therefore, the increase in inhibition efficiency (%I) and surface coverage (?) in the presence of the halides was found to be in a special sequence. . This synergistic effect increased according to the following pattern Cl- < Br -< I- suggesting a possible role by ionic radii in the corrosion inhibitory process which also increase in the order, F/F – ( 0.072/0.133nm), Cl/ Cl- (0.099/0.181nm) < Br/ Br - ( 0.114/ 0.195nm) < I/ I- ( 0.133/0.216 nm) . Fluoride ion does not show any inhibitory enhancement on Sida acuta owing to its least ionic radius..

Inhibitive action of 2-aminobezothiazole on the deterioration of AA6061-SiC composite in 0.5M HCl medium: Experimental and theoretical analysis

Electrochemical testing on AA6061-15% (V) SiC (P) composite corrosion in 0.5M HCl solution containing 2-aminobezothiazole (2-ABT) was performed. 2-ABT exhibited a good inhibition efficiency of 84% by acting as a mixed inhibitor. Polarisation studies showed a considerable reduction in corrosion rate, leading to increased inhibition efficiency with a rise in 2-ABT concentration. The increase in polarization resistance with a rise in 2-ABT concentration indicates the adsorption of 2-ABT on the composite, controlling corrosion. The evaluation of thermodynamic results revealed the physisorption of 2-ABT on the composite. The adsorption of 2-ABT followed Langmuir isotherm model. The surface morphological evaluation of composite specimens before and after inhibition supported the adsorption of 2-ABT on the composite. The results of quantum chemical calculations also confirmed the adsorption of 2-ABT.

Investigation Effect of 4-Aminophenol as a Corrosion Inhibitor for Mild Steel in Sulfuric Acid Medium

A high number of organic materials have been studied as inhibitors for corrosion in different conditions. In this paper, the effect of organic chemical (4-Aminophenol) as an inhibitor for mild steel metal corrosion was investigated in presence of sulfuric acid at different temperatures. The study was carried out using three known methods in testing corrosion process, methods of weight loss, thermometric, and polarization. The obtained results showed that when the inhibitor concentration increases, the corrosion rate decreases, and hence, the inhibition efficiency increases. Moreover, when the surface coverage at a temperature of 313 °C with organic inhibitor increases, the corrosion rate decreases as noticed in the weight loss method. For the thermometer method, the inhibitor was examined by temperature. The inhibition efficiency increases, as well as in the anodic and cathodic polarization method, where it is observed that the anodic and cathodic curves are present to measure the corrosion current and corrosion potential. As the higher the concentration of the inhibitor, the lower the current and the corrosion voltage. The reason for the effectiveness of this inhibitor is the presence of amine and phenol organic molecules in its composition, which can form a film on the metal surface and prevent corrosion from taking place.

Corrosion resistance of Aluminium steel in 1N Sodium Hydroxide solution by an aqueous extract of Thespesia populnea plant leaves

Corrosion resistance effect of aluminium steel in 1N sodium hydroxide by an aqueous extract of Thespesia populnea plant leaves has been investigated by mass loss method. It is observed that as the concentration of the inhibitor increases, the inhibition efficiency increases. The mechanistic aspects of corrosion resistance have been studied by potentiodynamic polarization technique and electrochemical impedance spectroscopy. A maximum inhibition efficiency of 78.70% is achieved by this inhibitor system. Potentiodynamic polarization technique reveals that the inhibitor system functions as a mixed type of inhibitor, controlling anodic and cathodic reactions. It is noted that in the presence of inhibitor, linear polarization resistance value increases and corrosion current decreases. Electrochemical impedance studies reveal that a protective film is formed on the Al steel surface, since in the presence of inhibitor system, the charge transfer resistance value increases and double layer capacitance value decreases. This is due to adsorption of the molecules of the active ingredients of the extract on the Al steel surface. The inhibition efficiency increases due to adsorption of hetero atoms present in TP plant leaves extract on the Al steel surface. The maximum inhibition efficiency and the lower corrosion rate are obtained at high concentration 1200 ppm for TP plant leaves extract. By further increase in inhibitor concentration above 1200 ppm, the inhibition efficiency and corrosion rate almost remained constant. So, the 1200 ppm concentration is fixed as the maximum inhibition for the investigative aqueous extract of plant leaves as corrosion inhibitor. This concentration corresponds to the attainment of a saturation value in surface coverage of Al steel. The protective film formed over the Al steel surface has been characterized by Fourier Transform infra-red spectroscopy. The surface morphology of the protective film of carbon steel immersed in sodium hydroxide in the absence and presence of inhibitor has been studied by Scanning electron microscopy. The outcome of the study can be used in pickling industry wherein sodium hydroxide is used to remove the rust on the Al steel surface.

Experimental studies of the inhibitory effect of thiamazole on copper corrosion in near neutral 3% sodium chloride solution

As the unused drugs which are disgracefully arranged can contaminate the environment, a conceivable application of unused pharmaceutical compounds as corrosion inhibitors was successfully implemented, in this context thiamazole was assessed as a potential copper corrosion inhibitor in near neutral 3% sodium chloride solution. Electrochemical methods, surface and solution analysis are used to explore copper corrosion and its resistance. Corrosion of copper and its inhibition by thiamazole have been investigated in 3% NaCl solution using Potentiodynamic polarization, Electrochemical impedance spectroscopy, X-rays diffraction analysis, Scanning electron microscopy (SEM) along with Energy dispersive X-ray spectroscopy(EDX),contact angle measurements, Inductively Coupled Plasma (ICP) and Ion chromatography(IC).According to polarization measures, thiamazole works as a mixed type inhibitor. The values of polarization resistance and inhibition efficiency increase with thiamazole concentration increase, according to electrochemical impedance spectroscopy data. After 24 h immersion time of copper sheets in free amd containing thiamazole solution, it was revealed that thiamazole behave as mixed-type inhibitor with an efficiency of 97%. SEM/EDX investigations confirm that thiamazole forms a protective and hydrophobic layer on copper surface, this finding was assessed by contact angle (CA) tests; these results are further supported by XRD patterns that show the removal of crystalline corrosion products. The results of inductively coupled plasmasolution analysis and ionic chromatography demonstrate that in the presence of 10-4 M thiamazole in the investigated solution, the concentration of chloride increased while the concentration of copper (II) ions decreased.The outlined findings infer that the used molecule plays a role of an environmentally friendly corrosion inhibitor.

Mild steel corrosion control through locally sourced calcium oxide on zinc phosphating process

Mild steel is vulnerable to corrosion, so its prevention is essential in order to sustain its wide applications in petroleum, food, electrical, chemical, and construction industries. This study investigated the corrosion control action of the locally sourced calcium oxide on the zinc phosphating process of mild steel. Varied concentrations of calcium oxide (0 – 2 g/L) and coating (phosphating) time (40–70 min) were considered during the phosphating of the pretreated mild steel samples at coating temperatures of 60 °C and 80 °C. The phosphate samples were subjected to weight loss tests utilizing a solution of NaCl (3.5 wt.%) at 25 °C, in order to determine both the sample corrosion rates and corrosion inhibition efficiencies. As both the calcium oxide concentration and phosphating temperature increased, the results trend (in general) showed a decrease in corrosion rate and increase in inhibition efficiency. Sample with the operating conditions of 70minutes coating time, 2.0 g/L calcium oxide in the bath at 80 °C coating temperature exhibited the best inhibition efficiency of 81% and lowest corrosion rate of 0.029 mm/year. SEM analysis revealed that the crystals of the coated surface became finer and had a more surface coverage owing to the increase in the concentration of calcium oxide (from 0.7 to 2.0 g/L). ΔGads values of close to -20 kJmol−1 obtained (from both Langmuir and Freundlich adsorption isotherms) revealed a spontaneous and physical adsorption process of calcium oxide on the sample surfaces. The calculated positive values of ΔHads and ΔSads established the phosphating (coating) process to be an endothermic process with increased randomness at the solid/liquid interface of the sample surface and bath solution.

The Inhibition Effect and Mechnism of a Thiadiazole Derivative on Q235 Carbon Steel in 1 M HCl Solution

N,N-dihydroxyethyl-(5-methyl-[1,3,4] thiadiazol-2-sulfur)-carbonyl acetamide was synthesized and used as an inhibitor to protect Q235 carbon steel in a 1 M HCl solution. The results showed an increased inhibition efficiency with the increase in the concentration of this inhibitor, and an inhibition efficiency higher than 96% at 40 mg/L can be obtained from weight loss, electrochemical impedance spectroscopy, and potentiodynamic polarization results. The inhibition effect was determined by the adsorption film according to the surface morphology and elemental distribution of the carbon steel surface. The adsorption consists of physical adsorption and chemical adsorption in view of the free adsorption energy of −40.64 kJ/mol derived from the Langmuir adsorption isotherm line. The lone pair electrons of N, O and S and π electronics of double bonds in molecules form stable covalent coordination bonds with the empty d orbitals of iron atoms, which is beneficial to chemical adsorption of the inhibitor. The high inhibiton efficiency of this inhibitor is important for the potential application in pickling field.

Multidimensional insight into the corrosion mitigation of clonazepam drug molecule on mild steel in chloride environment: Empirical and computer simulation explorations

In recent years, the use of drugs-based compounds to inhibit mild steel corrosion has grown significantly. Clonazepam stands out among other drug based compounds employed as potential corrosion inhibitors. This study investigates the experimental and computational properties of clonazepam drug molecule as mild steel corrosion inhibitor in chloride solution using weight loss, thermometric, electrochemical impedance spectroscopy, potentiodynamics polarization, surface imaging, Density Functional Theory, and molecular dynamic simulations. The findings demonstrate that as clonazepam drug concentration is increased, the inhibition efficiency increases, reaching a maximum of 90.1% for weight loss, 89.2% for thermometric investigations, 91.4% for electrochemical impedance spectroscopy, and 85.1% for (potentiodynamics polarization) techniques at 500 ppm. The clonazepam drug functions as a mixed-type corrosion inhibitor as demonstrated by the potentiodynamic polarization method. The clonazepam drug adsorption followed the Langmuir adsorption isotherm. The mild steel surface has a barrier layers covering it, as shown by the surface characterization studies via SEM and AFM. The highest occupied molecular orbital (EHOMO), the energy of the lowest unoccupied molecular orbital (ELUMO), the energy gap (ΔE), chemical hardness (η), softness (σ), dipole moment (μ) and electronegativity (Ɛ) were all evaluated for neutral and protonated forms respectively. The molecular dynamic simulations evidenced a near flat adsorption orientation on the Fe surface.

Acalypha wilkesiana acid extract as a potential green inhibitor for corrosion of mild steel in acidic medium: Thermodynamics and kinetics study

The use of synthetic compounds as corrosion inhibitor is diminishing due to strict environmental regulations and toxic effects of the compounds on human beings and the environment. Consequently, there exists the need to develop a new class of corrosion inhibitors with low toxicity, eco-friendliness and good efficiency. Therefore, this study investigates the inhibitory potential of Acalypha wilkesiana (AWAE) extract on mild steel in 1M HCl using weight loss method. Experiments were performed by varying immersion period, concentration of the inhibitor and temperature. The results obtained showed a decrease in the corrosion rate of mild steel as the extract concentration increases while the inhibition efficiency increases with extract concentration. Effect of temperature on the inhibition efficiency showed an increase in inhibition efficiency with rise in temperature. The adsorption of the inhibitor on the mild steel surface in acid solution was found to obey the Langmuir adsorption isotherm. Calculated thermodynamic parameters revealed that the mechanism of the corrosion inhibition may be due to the chemical adsorption of the phyto-constituents on the surface of mild steel. Kinetic treatment of the data followed a first order reaction and the half-life values of the metal increase with increase in the extract concentration. Preliminary investigation of the phytochemical constituents showed that Acalypha wilkesiana contains tannin, flavonoid, saponin, alkaloid, steroid , terpenoid and some other compounds in trace quantity. FTIR results indicate that AWAE contains O and N atoms in functional groups and aromatic ring which meet the general consideration of a typical corrosion inhibitor.

Experimental and theoretical studies on the corrosion inhibition on the surface of C-steel in hydrochloric acid solutions using N1, N1'-(ethane-1,2-diyl)bis(N2-(4-(di-methylamino)benzylidene)ethane-1,2-diamine)

The inhibition effect of N1,N1'-(ethane-1,2-diyl)bis(N2-(4-dimethyl-amino)benzylidene)-ethane-1,2-diamine), (EDDB) on the corrosion of C-steel in 1.0 M HCl solution was investigated using gasometry, gravimetry, potentiodynamic polarization, and electrochemical impedance spectroscopy. The impact of temperature and inhibitor concentration were explored to illustrate the mechanism of inhibition. The data showed that EDDB is a good inhibitor for the corrosion of C-steel in 1.0 M HCl solution. The inhibition is based on adsorption phenomena, which correlates to the Langmuir adsorption model. The inhibition efficiency increase with the EDDB concentration to reach a maximum value of 95.2% at 0.005 M and 25 °C. Potentiodynamic polarization data confirmed that the EDDB behaves as a mixed-type inhibitor. The negative values of ΔGoads confirm the stability of the formed film on the C-steel with a spontaneous process and take values between – 35.34 and - 39 kJ/mol depending on the temperature which confirms the physical- and chemisorption mechanism. The SEM/EDS data disclosed that the carbon steel was protected by the EDDB inhibitor. DFT computations and MC simulation were achieved on the EDDB Schiff-base inhibitor to correlate with experimental data. The results obtained from the different methods are in good agreement.

Effects of Extracts of Alchornea Cordifolia on Biocorrosion Control on Sewer Concrete

Concrete infrastructures that make up the sewer system exposed to sewer waste waters are often subjected to microbial corrosion. The biogenic sulfuric acid produced by the activity of sulfur-oxidizing bacteria A.thiooxidans attacks concrete in sewers leading to loss of concrete mass and deterioration.The aim of this study was to control concrete biodegradation using plant extracts of Alchornea Cordifolia. Concrete samples were corroded for 26 months in real sewer wastewater conditions. The influence of biogenic sulfuric acid on the biocorrosion of concrete samples was determined in terms of weight loss, pH, sulfate concentration variation, chemical composition changes, and formation of corrosion by-products. Recorded corrosion rates before coating were between 0.071996mpy –1.168546mpy. Changes in sample morphology, ettringite and gypsum formed were observed by X-ray diffraction and SEM methods with corrosion progression.Phytochemicals analysis of extracts samples confirmed the presence of tannins, saponins, flavonoids, and terpenoids produced in plant tissues. GC-MS analysis of the ethanolic extracts identified 26 compounds.The most dominant being Eugenol.Biocorrosion control determined the effects of extracts on concrete corrosion in sewer waters. A marked decline in the rates of corrosion with each extract's coating was recorded for extracts coated concretes (0.002589mpy-0.003256mpy). An increase in inhibition efficiency with an increase in extract concentration was observed and was in the range of50% A.Cordifolia extracts gave the highest inhibitor efficiency. X-ray diffractive analysis and scanning electron microscopy showed morphological variations in concrete before and after coating. Results of ANOVA showed inhibitor concentration as having the most significant effect on the extracts' corrosion inhibition