Corrosion Inhibition Of Steel Research Articles

Grape Leaves and Ziziphus Spina-Christi, Extracts as a Green Inhibitors Corrosion for The Carbon Steel and Oil Pipelines in 1M H2SO4

Metals suffer from corrosion by the surrounding fluids, which causes great economic losses and bad environmental effects, especially in oil pipelines or reservoirs. The extract of grape leaves (GL) and Sidr leaves, (Ziziphus spina-christi), (Zizi) were used as green corrosion inhibitors (CI) for carbon steel (CS), and Oil Pipelines in 1M H2SO4, these extracts showed varying capabilities in resisting corrosion. Corrosion rate was decreased with increase in inhibitor dose which could be due to enhanced surface coverage, as well as the effect of increasing the temperature on the percentage of the efficiency of inhibition, are decrease, and drawing the curves for that, as well as studying some physical properties related to the process of adsorption of extracts on the surface of (CS), such as the activation energy and entropy of the process of adsorption of the extracts on the surface of (CS), and calculating those values, and the extracts showed an efficiency that exceeded 90% at concentrations up to 400 ppm and a temperature of 313-343K. The activation energy associated with this process indicated surface interaction as the main mechanism and positive values of enthalpy change confirmed the endothermic nature. The potentiometric method showed the extent of voltage change with time for each concentration of extract of grape leaves for immersion time (2–24 h), and that the voltage increases with increasing concentration, which indicates a high ability of the inhibitor to adsorb to the metal..

Synthesis and characterization of a new eco-friendly dopamine derivative schiff base as an effective corrosion inhibitor for mild steel in acidic environment

The natural corrosion inhibitor behaviour of a newly synthesized dopamine derivative Schiff base (4-DBAB) has been inspected on mild steel in aggressive 1 M HCl using linear polarization, electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The Schiff base was synthesized by eco-friendly pathway. Characterization of the synthesized new non-toxic inhibitor was performed using FT-IR and 1H-NMR spectroscopy techniques. The anti-corrosive efficiencies at optimum concentration of 4-DBAB inhibitor was 87.4% after 1 h and 98.4% after 120 h by impedance technique in acidic solution. The potential of zero charge of mild steel was also determined to elucidate the inhibition mechanism in the presence of the highest 4-DBAB solution. The atomic force microscopy and field emission scanning electron microscopy researches performed on surface morphology to provide additional support on the interaction between the mild steel surface and 4-DBAB molecules. Adsorption behaviour of the inhibitor was also studied at different durations by experimental inhibition results and showed the Langmuir isotherm involving chemisorption. Highlights A new dopamine-derived Schiff base (4-DBAB) with natural and environmentally friendly corrosion inhibition properties was synthesized. (Synthesis of eco-friendly compound). 4-DBAB demonstrated a high anti-corrosive efficiency after 120 hours in aggressive 1M HCl, as determined by impedance technique. (Exceptional corrosion inhibition). The determination of the potential of zero charge of mild steel provided insights into the inhibition mechanism in the presence of the highest 4-DBAB solution. (Mechanism elucidation). AFM and FE-SEM studies on surface morphology supported the interaction between the mild steel and 4-DBAB molecules, affirming its corrosion inhibition properties. (Surface interaction analysis).

Synthesis and characterization of selenium-polyvinyl alcohol nanoparticles as eco-friendly corrosion inhibitor for carbon steel in 1.0 M H2SO4

Synthesis and characterization of selenium-polyvinyl alcohol nanoparticles as eco-friendly corrosion inhibitor for carbon steel in 1.0 M H2SO4

Corrosion inhibition of acid pickling –descaling-cleaning action on mild steel using aqueous hydroxyethyl cellulose

The corrosion inhibition capability of aqueous Hydroxyethyl cellulose (HEC) on mild steel corrosion in 1 M HCl solution proposed for mild steel pickling, industrial cleaning, and descaling was evaluated at different concentrations and immersion times using gravimetric measurement. HEC demonstrated efficiency in mild steel corrosion inhibition with a maximum inhibition efficiency of 87% for a 300 ml acid pickling, industrial cleaning, and descaling solution composed of 20% aqueous solution of 0.01 M HEC and 80% of 1 M HCl solution, within an immersion time of 120 hours. The inhibition efficiency was found to increase with the increase in the concentration of HEC implying that HEC’s inhibition action is concentration and time-dependent. The mechanism of adsorption of HEC was identified to be chemisorption with hydroxyl (-OH) moiety donated to the active sites of mild steel coupled with HEC molecules encapsulation of chloride ions on mild steel surface thus preventing the corrosive action of Cl ions on the mild steel.

Synthesis and Performance of a New and Simple Schiff Base Structure for Corrosion Inhibition of C38 steel in 1 M HCl Solution: Experimental Studies and DFT Investigation

In order to investigate the corrosion of carbon steel (C38) in acidic media, experimental studies (weight loss measurements, electrochemical methods, thermodynamic adsorption isotherms and field emission scanning electron microscopy coupled with energy dispersive X-ray) and computational approach were adopted to study the newly synthesized and simple Schiff base structure, namely 4-((phenylimino)methyl) phenol (PIMP) as a corrosion inhibitor for C38 steel in 1M HCl. Characterization techniques (Fourier Transform Infrared spectroscopy, mass spectrometry, proton nuclear magnetic resonance) showed that PIMP was successfully synthesized with a yield of 63%. Experimental methods (weight loss, open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP)) showed that PIMP is a mixed-type inhibitor with an inhibition percentage of 91.1% under optimal conditions (7.5 mM PIMP at 30°C). These experimental results were supported by surface analysis (Field Emission Scanning Electron Microscopy (FESEM) coupled with Energy Dispersive X-Ray (EDX)), where PIMP molecules are adsorbed on the steel surface and form a protective barrier against aggressive ions, thereby limiting steel oxidation. The adsorption of PIMP on the carbon steel surface followed the Langmuir adsorption isotherm along with a mixture of physical and chemical adsorption, forming a complete and dense protective film on the C38 steel surface. Theoretical results using density functional theory (DFT) calculations showed that PIMP contains highly reactive centers and confirmed the experimental results obtained.

Electrochemical and Quantum Chemical Investigations of novel pyrazole derivatives as a Corrosion Inhibitor for Stainless Steel in 2M H2SO4 medium

Stainless steels play a crucial role in diverse industrial domains. However, due to their exposure to acidic environments, stainless steels undergo the corrosion phenomenon, leading to the deterioration of the material and its properties. Thus, the objective of this work is to study the corrosion inhibition of stainless steel in an H2SO4 2M medium by using two organic compounds, namely Py-3:{1-amino-5,10-dioxo-3-(p-tolyl)-5,10-dihydro-1H-pyrazolo[1,2-b] phthalazine-2-carbonitrile} and Py-4:{1-amino-3-(2-chlorophenyl)-5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b]phthalazine-2carbonitrile}. This study was conducted using transient electrochemical methods in conjunction with a theoretical approach. The obtained results demonstrate that the addition of pyrazole compounds in the corrosive medium H2SO4 exhibits excellent inhibitory power against steel corrosion, with an inhibitory efficiency reaching 98%. The tested inhibitors are adsorbed into the surface of the metal by chemical bonds, Moreover, the adsorption of these compounds follows the Langmuir adsorption model. Theoretical calculations based on the Density Functional Theory (DFT) provide a better understanding of the reactivity of tested inhibitor towards stainless steel which they are in good agreement with the experimental findings.

An investigation of modified dialdehyde starch as a highly efficient green corrosion inhibitor for carbon steel in 1 M HCl medium: Synthesis, experimental and theoretical studies

Compared to small organic molecule corrosion inhibitors, polymer corrosion inhibitors offer numerous advantages in terms of adsorption coverage on the metal surface and the presence of multiple active sites for adsorption. A dialdehyde starch Schiff base was synthesized by modification of natural polymer starch and tetraethylene pentaamine, and it was characterized by X-ray diffraction, gel chromatography and thermogravimetry. The corrosion inhibition behaviors of dialdehyde starch Schiff base as an oligomer for low carbon steel in 1 M HCl were investigated. Compared to the common starch derivatives, the dialdehyde starch Schiff base has good water solubility and inhibition performance. The inhibition efficiency can reach 93.2% with 0.16 mM in 1 M HCl solution at 333 K. Double aldehyde starch Schiff base is a mixed corrosion inhibitor that mainly inhibits cathodic reactions. Its adsorption on the surface of carbon steel follows the Langmuir adsorption equation, and the nitrogen -containing groups in the molecules are adsorbed on the surface of the steel through physical and chemical reactions. Quantum chemical calculations confirmed the experimental results.

Evaluating the efficacy of newly synthesized amino acid derivatives as corrosion inhibitors in acidic solutions

Three benzimidazole derivatives, with tryptophan (BIT), tyrosine (BIY), and histidine (BIH) amino acid units, have remarkable protective properties as eco-friendly corrosion inhibitors for steel under severe acidic conditions. At a temperature of 303 K, the corrosion inhibition efficiency of BIT, BIY, and BIH at a concentration of 10 mM is 90.09 %, 92.53 %, and 93.43 %, respectively. Electrochemical tests indicate that the adsorption of these substances on the substrate leads to an increase in charge transfer resistance and interfacial electric double layer thickness. This effectively hinders the dissolution of metal and the evolution of hydrogen. The analysis of the surface structure and appearance using SEM-EDS indicates that the inhibitors have the ability to create a protective coating through both chemical and physical bonding, effectively protecting the metal from corrosive substances. Theoretical calculations, such as Density Functional Theory (DFT) and Natural Bond Orbital (NBO) analysis, along with FUKUI analysis, help identify active sites and adsorption configuration. This enhances our understanding of the corrosion mitigation mechanism. These findings align with the experimental conclusion that the formation of a stable protective film contributes to superior inhibition performance against acidic corrosion conditions.

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

Assessment of Azolla Microphylla Plant Extract as an Environmentally Benign Corrosion Inhibitor for Low-Carbon Steel in Acidic Media

Assessment of Azolla Microphylla Plant Extract as an Environmentally Benign Corrosion Inhibitor for Low-Carbon Steel in Acidic Media

Protein-derived carbon dots as green corrosion inhibitors for carbon steel in sulfuric acid solution

At present, the development of eco-friendly corrosion inhibitors (CIs) is considered an important and attractive method for controlling the corrosion of metals in acidic media. In this study, protein-derived carbon dots (P-CDs) were prepared via hydrothermal reaction using protein as the raw material, and the corrosion inhibition performances of P-CDs for carbon steel (CS) were investigated systematically. The electrochemical test results showed that the corrosion inhibition efficiency of 500 mg/L P-CDs on CS reached 95.1 % in 0.5 M H2SO4, and the corrosion inhibition efficiency was enhanced to 98.1 % after 8 h of immersion time. The composition and characterization of P-CDs was analysed using Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet Spectroscopy (UV), X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) characterization showed that the surface of CS with P-CDs was smoother than that without P-CDs, and that P-CDs was able to adsorb on the surface of CS to form a protective layer, thereby inhibiting corrosion. Adsorption studies indicate that P-CDs form a protective layer on the surface of CS through both physisorption and chemisorption. Overall, these findings demonstrate that P-CDs exhibit superior protective effects against the corrosion of CS in 0.5 M H2SO4.

Synthesis and evaluation of a novel pyridinyl thiazolidine derivative as an antioxidant and corrosion inhibitor for mild steel in acidic environments

A new synthesized (Z)-2-((3,5-dichloropyridin-2-yl)imino)thiazolidin-4-one (DICPT) was evaluated as an antioxidant and a corrosion inhibitor for mild steel (M.STL) in a 0.5 M HCl solution. The antioxidant activity of newly synthesized DICPT was screened using a DPPH assay, and the results showed that DICPT has good antioxidant activity. Electrochemical assessments were conducted utilizing potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). A new compound, DICPT, was synthesized, and its chemical structure was established and validated through various spectroscopic techniques, including including infrared (FTIR), nuclear magnetic resonance (NMR), and mass spectroscopy. PDP measurements revealed DICPT to be a mixed-type inhibitor. Charge transfer resistance (Rct) increased when inhibitor concentrations increased, according to EIS tests. The inhibition efficiency (%I) showed a corresponding rise with increasing inhibitor concentration, peaking at approximately 94.2 % at 3 × 10−5 M. Langmuir’s adsorption isotherm was found to govern the preferred adsorption mode of DICPT molecules onto the metal surface. UV–visible spectra confirmed the chemical interaction between DICPT molecules and the M.STL surface. AFM investigation indicated the formation of a protective layer on the metal surface, shielding it from corrosive environmental factors. Quantum chemical calculations were compared to experimental results to learn more about how corrosion is stopped and how well it works. Our study demonstrates the innovation of DICPT as a dual-function compound, offering both antioxidant and corrosion protection properties. This research contributes to the development of effective corrosion inhibitors for industrial applications.

Research on synthesis of imidazole-based ionic liquids as metal corrosion inhibitors

Ionic liquids (ILs) have gained significant attention in recent years as potential corrosion inhibitors to various applications. Traditional corrosion inhibitors, such as organic compounds and inorganic salts, have limitations in terms of toxicity, volatility, and environmental impact. However, ionic liquids offer a promising alternative. Ionic liquids are salts that exist in a liquid state at or below 100 degrees Celsius. They typically comprise an organic cation and an inorganic or organic anion. The unique combination of a liquid state and ionic nature gives them several advantageous properties, such as high thermal stability, low vapor pressure, and tunable physicochemical properties. Additionally, the charged nature of the ionic liquid allows for electrochemical interactions with the metal surface, further enhancing corrosion inhibition. In this paper, imidazole-based ionic liquids were synthesized by alkylation of imidazole derivatives using 1-bromohexadecane. The anti-corrosion properties of the material were evaluated using the weight method and potentiodynamic polarization method. Results showed that the synthesized ILs are good corrosion inhibitor for CT3 steel.

Inhibition of Carbon Steel Corrosion Using Dextran Derivatives in Circulating Cooling Water

Developing environmentally friendly and biodegradable corrosion inhibitors is an important research direction due to the toxicity and non-degradability of conventional carbon steel corrosion inhibitors added to circulating cooling water environments. Polysaccharides in EPSs (Exopolysaccharides) can be used as green corrosion inhibitors, but a low inhibition rate limits their practical application. Chemical modification is widely used to modify the functionality of polysaccharides by altering their physicochemical properties and structures, thereby enhancing or supplementing their functional characteristics. In this study, we employed chloroacetic acid as an esterifying agent to chemically modify Dextran and successfully synthesized a modified polysaccharide derivative with a substitution degree of 0.326. This derivative efficiently inhibited the corrosion of carbon steel in circulating cooling water environments. The carboxymethylated dextran (CM-Dextran) formed after synthesis could adsorb onto metal surfaces to form a protective film, thereby inhibiting metal surface dissolution reactions and exhibiting anodic corrosion inhibition properties. The experimental results showed that the corrosion inhibition efficiency of CM-Dextran after modification increased by up to 57.4%, with a maximum inhibition efficiency of 82.52% at a concentration of 4 mg/mL. This study provides new insights and opportunities for the development of environmentally friendly corrosion inhibitors derived from polysaccharides.

Corrosion inhibition of mild steel by Praecitrullus fistulosus (tinda fruit and peel) extracts

Metal corrosion has recently emerged as a growing concern, impacting both local and industrial operations and disrupting conventional production methods. The utilization of green inhibitors to mitigate the metal degradation has garnered extensive attention from researchers and industrial professionals due to their prominent advantages: high efficiency, cost-effectiveness, and eco-friendliness. A novel ecofriendly inhibitor was prepared from Praecitrullus fistulosus (tinda fruit and peel) for mild steel (MS) corrosion in 1 M HCl. The presence of phenol, 3,5-bis (1,1-dimethyl ethyl)-, 9-octadecenoic acid, methyl ester, hexadecanoic acid 15-methyl-, methyl ester, 9, 12-octadecadienoic acid, methyl ester, 9, 12, 15-octadecatrienoic acid, methyl ester, (Z,Z,Z-), ascorbic acid, and phytol were identified as major constituent through LC/MS analysis of tinda extracts. The existence of these compounds was further confirmed through FTIR analysis, which shows the presence of various functional groups, such as -OH, CO, C-O-C, CC, and aromatic rings in the tinda extracts. Electrochemical and gravimetric analyses were used to investigate the inhibitory effect of tinda extracts. Outcomes of Tafel analysis revealed that both tinda extracts significantly reduced the corrosion current as compared to blank and achieved 83.73 % and 87.59 % inhibition efficiencies at 200 mg L−1 of tinda peel extract (TPE) and tinda fruit extract (TFE), respectively. The change in corrosion potential (Ecorr) was within an ±85 mV range compared to that of the uninhibited system, indicating that both tinda extracts demonstrated a mixed-type inhibition behavior. During adsorption studies, the best fit was obtained for the Langmuir adsorption model. The obtained values of standard Gibbs free energy (ΔG°ads) for TPE and TFE lie between −20 and − 40 kJ mol−1 but close to −20 kJ mol−1, which reveals preferential physical adsorption of the extracts on the metal surface. Thermodynamic parameters, including activation energy, enthalpy, and entropy, were computed across the temperature range of 303 to 323 K, suggesting that corrosion occurs spontaneously by the endothermic process. FESEM analysis depicted that inhibited systems exhibited smooth and crack-free surfaces as compared to blank system. AFM images demonstrated that surface roughness was significantly reduced for the inhibited system. In EDX analysis, the weight percentage of Cl was reduced in the presence of tinda extracts as compared to blank, and in XRD analysis, iron chloride (FeCl2) peak did not appear in the presence of inhibitor but it was in the uninhibited system. All surface-related findings signify that tinda extracts are adsorbed on the MS surface and form a protective layer that separates the metal from the corrosive solution.

Furosemide drug as a corrosion inhibitor for carbon steel in 1.0 M hydrochloric acid

Furosemide (4-chloro-2-furan-2-ylmethylamino-5-sulfamoylbenzoic acid) was examined as an inhibitor for the corrosion of carbon steel (CS) in 1.0 M HCl. The investigation included mass loss (ML) and electrochemical techniques: potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM). The efficiency of inhibition rises with increasing Furosemide concentration and temperature. This compound follows the Temkin isotherm with good fit. The presence of varying quantities influences both anodic metal dissolution and cathodic hydrogen evolution. Scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) were used to detect the effect of the compound on the CS surface. The molecular inhibitory effect of Furosemide was demonstrated using quantum chemical calculations, and the molecular simulation results demonstrated the adsorption on the carbon steel surface.

Green Synthesizing and Corrosion Inhibition Characteristics of Azo Compounds on Carbon Steel under Sweet Conditions: Experimental and Theoretical Approaches.

The deterioration of carbon steel in saline solutions enriched with carbon dioxide represents a significant challenge within the oil and gas industry. So, this study focuses on the design and structural analysis of four azo derivatives: 4-(2-quinolinylazo)-catechol (AZN-1), 4-(4-phenoxyphenylazo)-1-naphthol (AZN-2), 4-(4-pyridylazo)-1-naphthol (AZN-3), and 4-(2-pyridylazo)-1-naphthol (AZN-4), and their first application as effective corrosion inhibitors for carbon steel in a carbon dioxide saturated 3.5% sodium chloride solution. Spectroscopic methods were used to characterize the structural configurations of these compounds. The corrosion protection properties of these compounds on carbon steel in a carbon dioxide saturated 3.5% sodium chloride solution (under sweet conditions) were investigated using Tafel polarization (PDP), electrochemical impedance spectroscopy (EIS), and field emission-scanning electron microscopy (FE-SEM) studies. The results indicate that the inhibition efficiency increases as the concentration of the inhibitors increases. There is a notable agreement between the results obtained from the PDP and EIS measurements, supporting the findings. Moreover, the results displayed that these compounds had significant corrosion protection capabilities at low concentrations, ranging from 91.0 to 98.3% at an additive concentration of 5 × 10-4 M. The PDP profiles showed that these compounds acted as mixed inhibitors, and their adsorption behavior followed the Langmuir isotherm model. Besides, EIS results corroborate the adsorption of AZN compounds through a reduction in double-layer capacitance (Cdl) alongside an augmentation in polarization resistance (Rp) after the addition of AZN compounds into the corrosive solution. Field emission scanning electron microscopy (FE-SEM) and Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the formation of a protective layer on the surface of carbon steel when these inhibitors were applied. In addition, computational calculations and Monte Carlo simulations were performed to support the experimental observations, gain insights into the adsorption properties, and elucidate the corrosion inhibition mechanisms of these compounds.

Experimental and theoretical investigation of novel ammonium-derived dihydroxyl ionic liquid as corrosion inhibitor for mild steel in 1 M HCl: Effects of dihydroxyl and head groups

A novel ammonium-derived dihydroxyl ionic liquid ([C16DPOA]Br) and a control ionic liquid ([C16DPA]Br) are synthesized to reveal the effect of dihydroxyl and head groups on their inhibition property via the weight-loss method, surface analysis, electrochemical measurements, and adsorption isotherm studies. [C16DPOA]Br exhibits the optimal inhibition ability (93.47 %) for mild steel in 1 M HCl in contrast to [C16DPA]Br (88.03 %) and the traditional cationic surfactant CTAB (92.34 %). Based on the experimental results, it can be inferred that the short alkyl chain (propyl) impedes the tight alignment of [C16DPA]Br on the metal surface and the interactions between hydroxyl and iron atoms enable [C16DPOA]Br to overcome the negative effects of the short alkyl chain on the inhibition property. Finally, molecular electrostatic potential (MEP) distribution and molecular dynamics (MD) simulation verify the reactive sites and adsorption capacity of corrosion inhibitors from the microscopic scale, which further confirms the proposed mechanism. This study focuses on the significance of dihydroxyl and head groups on the inhibition property and provides unique insights into the development of efficient ionic liquid corrosion inhibitors.

Synthesis and Application Insights of New Phosphate Materials A2MnP2O7 (A = Na, K, Li) as Corrosion Inhibitors

This study comprehensively characterizes synthesized phosphate materials, specifically A2MnP2O7 (where A represents Na, K, or Li), utilizing the X-ray diffraction (XRD) and infrared (IR) spectroscopy techniques. The XRD results corroborate the crystalline nature of these compounds, while the IR spectra disclose pivotal structural characteristics, including the bent geometry of the POP bridge. A significant observation is the mismatch of specific IR bands, suggesting a non-centrosymmetric arrangement in the A2MnP2O7 crystal lattice. The synthesized materials were evaluated as corrosion inhibitors for mild steel (MS) in 3 wt.% NaCl. Electrochemical assessments indicate that these materials act as mixed-type inhibitors, demonstrating high inhibition efficiencies (η%), reaching peak values of 88.3% for Na2MnP2O7, 87% for K2MnP2O7, and 86.7% for Li2MnP2O7 at a concentration of 10−3 mol/L. The study also elucidates the thermodynamic and kinetic parameters dictating the inhibition phenomena. Additionally, scanning electron microscopy (SEM) was employed to examine the surface morphology of mild steel in the presence of these inhibitors.

Enhanced Corrosion Inhibition of Q235 Steel by N,S Co-Doped Carbon Dots: A Sustainable Approach for Industrial Pickling Corrosion Inhibitors.

A high yield of environmentally friendly N,S-codoped (N,S-CDs) and N-doping carbon points (N-CDs) carbon dots was achieved through a biochemical oxidation reaction at room temperature in this study. Acetaldehyde, sodium hydroxide, benzotriazole (BTA), and 2-mercaptobenzimidazole (MB) with a similar structure were used as raw materials. The microstructure and properties of the corrosion inhibitor for Q235 steel were evaluated by various experiments. The results demonstrated enhanced corrosion inhibition rates of the N,S-CDs compared to the N-CDs using electrochemical tests (93.83% vs 77.65%) and weight loss experiments (96.35% vs 91.65%) at 50 mg/L, respectively, compared to the blank material, indicating that N,S codoping can significantly improve the corrosion inhibition effect of carbon dots. The significant improvements were attributed to the formation of dense adsorption films and the hydrophobic properties of N and S-CDs nanoparticles on the steel surface, leading to an effective barrier against corrosion. The findings from this study provide important experimental data for potential industrial applications and hold important practical value in the field of pickling corrosion inhibitors.