HCl Medium Research Articles

Vibrational Spectroscopy and electrochemical study of MCuP2O7 (M = Ba, Ca and Zn), improvement of corrosion resistance of mild steel in 1.0 M HCl medium

The three diphosphates materials MCuP2O7(M = Ba, Ca and Zn) were synthesized by solid-state reaction and characterized. Using X-ray powder diffraction, infrared and Raman spectroscopy. The external and internal normal modes of these materials were studied by the factor group analysis. The analysis of the infrared and Raman spectra shows the non-linearity of the POP bridge. And also, that the structures of these salts are centrosymmetric. These materials have been studied in order to investigate its electrochemical behavior for corrosion resistance of mild steel in a corrosive medium (HCl 1.0 M). The inhibition performance of the three materials was evaluated by the open circuit potential (OCP), potentiodynamic polarization technique (PDP) and electrochemical impedance spectroscopy (EIS). The morphology of mild steel was examined by scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The results show that the three materials have good efficiency for the mild steel corrosion inhibition with a percentage reaches 89% for Ba based material.

On the Use of Pseudo-Protic Ionic Liquids to Extract Gold(III) from HCl Solutions.

Solvent extraction of gold(III) from HCl media using pseudo-protic ionic liquids (PPILs) dissolved in toluene as the extractant phase is investigated. Three PPILs are generated from the reaction of commercially available amines and 1 M HCl solution and named as pri-NH2H+Cl- (derived from the primary amine Primene 81R), sec-NHH+Cl- (derived from the secondary amine Amberlite LA2) and ter-NH+Cl- (derived from the tertiary amine Hostarex A327). In the above structures, -NH2H+Cl-, -NHH+Cl- and -NH+Cl- represented the active groups (anion exchangers) of the respective PPIL. In the case of gold(III) extraction, the experimental variables investigated included the equilibration time (2.5-30 min), temperature (20-60 °C), HCl concentrations (1-10 M) in the aqueous phase, gold(III) concentration (0.005-0.05 g/L) in this same phase, and PPILs concentrations in the organic phase. From the experimental data, and using the Specific Interaction Theory, the interaction coefficients (ε) for the pair AuCl4-, H+ are estimated for the systems involving the three PPILs. Gold(III) is recovered from the metal-loaded organic phases using sodium thiocyanate solutions, and from these, gold is finally recovered by the precipitation of zero-valent gold (ZVG) nanoparticles.

A novel phthalocyanine based discotic liquid crystal for efficient corrosion inhibition of mild steel

ABSTRACT Discotic liquid crystals have been extensively investigated for their applications in electro-optical devices. Very recently their potential as corrosion inhibitor has been realised. Effective methods for the prevention of corrosion of mild steel (MS) are still challenging research for industrial chemists. In the present work, MS samples in 1.0 M HCl medium were used to test the corrosion inhibition capacity of a metal-free phthalocyanine (Pc)-based discotic liquid crystal (DLC) using potentiodynamic and electrochemical impedance parameters. The phthalocyanine discotic liquid crystal (PcDLC) exhibited an excellent corrosion inhibition with a maximum inhibition efficiency of 89.61%. This superior ability was attributed to the strong adsorption of PcDLC on to the surface of mild steel as confirmed from the potentiodynamic polarisation data that fit into the cathodic inhibitor category. The protective layer of inhibitors generated on the MS surface was examined using scanning electron microscopy (SEM) and FTIR. The density function theory (DFT) approach was used to investigate the relationship between molecular structures and inhibitory efficacy, which indicated a strong interaction between the inhibitor and the surface iron atoms.

Phytochemical Characterization, Antioxidant Proprieties and Electrochemical Investigations of Methanolic Extract of Rubia t.L. Roots for LC-Steel Corrosion Protection in 1 M HCl Medium

Phytochemical Characterization, Antioxidant Proprieties and Electrochemical Investigations of Methanolic Extract of Rubia t.L. Roots for LC-Steel Corrosion Protection in 1 M HCl Medium

Synthesis, Characterization and Corrosion Inhibition study of N-(4-((4-(pyridin-2-yl) piperazin-1-yl) methyl) phenyl) quinoline-6-carboxamide on Mild Steel under HCl Solution

Objectives: To use the newly synthesized efficient organic corrosion inhibitor N-(4-((4-(pyridin-2-yl) piperazin-1-yl)methyl)phenyl)quinoline-6-carboxamide to carry out on mild steel corrosion inhibition study. Methods: N-(4-((4-(pyridin- 2-yl)piperazin-1-yl)methyl)phenyl)quinoline-6-carboxamide was synthesized by stirring method under 0oC to room temperature at 12 hrs. The synthesized organic inhibitor was characterized by 1H NMR, 13C NMR, UV and FTIR spectroscopy. The inhibition effect of organic inhibitor on the mild steel corrosion was investigated with weight loss measurement by gold measuring weighing balance. The inhibitor anchored down on the mild steel surface was analyzed by scanning electron microscopy and Atomic Force Microscopy. Findings: The inhibitor shows a better inhibition efficiency of maximum 74.41% in 1N HCl medium. In addition to this adsorption isothermal models were also interpreted to fit the adsorption behavior of the inhibitor compound on mild steel surface. Thus, the result shows the Langmuir adsorption isotherm. As a result, the interactions between inhibitor and mild steel surface have chemisorptions. Novelty: The N-(4-((4-(pyridin-2-yl) piperazin-1-yl)methyl)phenyl)quinoline-6-carboxamide shows better corrosion inhibition efficiency (74.41%). In addition, inhibitor and mild steel surface show chemisorptions interaction, which confirms free energy and enthalpy of adsorption. Keywords: Carbaxamide Derivative; Scanning Electronic Microscopy; Atomic Force Microscopy Weight Loss Measurement And NMR

Anti-Corrosion Coating Formation by a Biopolymeric Extract of Artemisia herba-alba Plant: Experimental and Theoretical Investigations

In this modest work, a local biopolymer (CHA), biodegradable, non-toxic, and soluble in acidic media, was extracted from the plant Artemisia herba-alba located in the eastern region of Morocco, and characterized by FT-IR, in order to valorize it as a corrosion inhibitor of mild steel in 1 M HCl medium. The electrochemical tests show that the extract is an excellent corrosion protective agent, reaching a maximum value of 96.17% at the concentration of 800 mg/L in the inhibitor. The potentiodynamic polarization (PDP) curves indicate the mixed behavior of the extract, to reduce the current density from 3.445 mA/cm2 to 0.104 mA/cm2 in the presence of 800 mg/L in the inhibitor. The biopolymer CHA of the extract of Artemisia herba-alba undergoes the Langmuir adsorption isotherm, whose adsorption energy is −20.75 kJ/mol, which is attributed to the presence of electrostatic and covalent bonds. In addition, the visualization of the metal surface by a scanning electron microscope (SEM) indicates the formation of a protective layer formed by the extracts of Artemisia herba-alba, which confirms the protective characteristic of the extract used. Theoretical investigations by DFT, MD, and MC confirm previous experimental results.

Experimental and computational studies on the corrosion mitigation properties of a newly synthesized imine derivative for carbon steel in HCl medium

A new imine derivative, namely 4-amino-2-((2,4 dihydroxybenzylidene)amino)-4 oxobutanoic acid (ADAO), was synthesized, characterized, and evaluated as a corrosion inhibitor for carbon steel (CS) in 1.0 mol/L HCl. Its molecular structure was elucidated by different spectroscopic analysis methods such as UV, FTIR, 1H, and 13C NMR. The corrosion inhibition behavior was investigated by weight loss, electrochemical techniques, surface analysis, and computational approaches (quantum chemical calculations and molecular dynamics (MD) simulations). Obtained outcomes showed that the ADAO displayed excellent effectiveness for CS corrosion inhibition, and its inhibition performance raised with its concentration reaching a maximum inhibition efficiency of 97.24% at 10−4 mol/L. Moreover, the influence of immersion time and temperatures were investigated and discussed. The adsorption behavior of the studied inhibitor followed Langmuir isotherm and revealed the presence of both physical and chemical processes upon interaction with the steel surface. Potentiodynamic polarization (PDP) outcomes demonstrated that ADAO acts as a mixed type inhibitor. EIS results showed that the charge transfer resistance Rct increases and double layer capacitance Cdl decreases in the presence of the synthesized imine, which suggests their adsorption on the steel surface. SEM analysis revealed the formation of a protective film on the carbon steel surface. Quantum chemical calculations indicated that the CN is the privileged site for the adsorption of the ADAO on the iron surface.

Corrosion protection studies of different alloys in 1 M HCl by benzimidazole derivative: Combined molecular dynamic simulations/DFT

Corrosion prevention of metals like Steel, Aluminum, and Copper is an interesting problem in industries, to solve this problem corrosion inhibitors are one of the most effective applications for metal protection against corrosion in aggressive media. The effect of (2E)-3-(6-phenylimidazo[2,1-b][1,3]thiazol-5-yl)-1-(2,4,6-trimethylphenyl)prop-2-en- 1-one (KO38) on the protection of steel, aluminum, and copper in 1 M HCl medium was examined using electrochemical polarization tests to assess inhibition efficiency, also scanning electron microscopy (SEM) to analyze the surface of metals. The maximum protection capacity of KO38 by the method of polarization is between 96% and 97% for the three metals exposed in an acid solution containing 10−4 M. The organic inhibitors can be classified as mixed-type inhibitors since they inhibited both anodic corrosion and cathodic corrosion. The study of the dynamic simulation (DM) helped to visualize the energies of adsorption of the molecule (KO38) on the interfaces of Iron (110), Aluminum (111), and Copper (111), the calculations of quantum chemistry were analyzed by (DFT) at B-3LYP /6–311 G (d, p). The experimental results are in good agreement with the theoretical studies.

Synthesis and characterization of novel acrylamide derivatives and their use as corrosion inhibitors for carbon steel in hydrochloric acid solution

Two new acrylamide derivatives were prepared namely: “N-(bis(2-hydroxyethyl) carbamothioyl) acrylamide (BHCA) and N-((2-hydroxyethyl) carbamothioyl) acrylamide( HCA) and their chemical structures were analyzed and confirmed using IR and 1H NMR”. These chemicals were investigated as corrosion inhibitors for carbon steel (CS) in 1 M HCl medium using chemical method (mass loss, ML), and electrochemical techniques including potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). The results showed that the acrylamide derivatives work well as corrosion inhibitors, with inhibition efficacy (%IE) reaching 94.91–95.28% at 60 ppm for BHCA and HCA, respectively. Their inhibition depends mainly on their concentration and temperature of the solution. According to the PDP files, these derivatives function as mixed-type inhibitors that physically adsorb on the CS surface in accordance with the Langmuir adsorption isotherm, creating a thin coating that shields the CS surface from corrosive fluids. The charge transfer resistance (Rct) increased and the double layer capacitance (Cdl) decreased as a result of the adsorption of the used derivatives. Calculated and described were the thermodynamic parameters for activation and adsorption. Quantum chemistry computations and Monte Carlo simulations were examined and discussed for these derivatives under investigation. Surface analysis was checked using atomic force microscope (AFM). Validity of the obtained data was demonstrated by the confirmation of these several independent procedures.

Rosemary extract inhibitive behavior against mild steel corrosion in tempered 1 M HCl media

Recent industrial issues are quite noteworthy for researchers that encourage them to introduce unique approaches to solve them. Among all, corrosion disasters were nominated as the most important ones. Although various routes were introduced for substantial corrosion limitation, inhibits were highly appreciated for worldwide industrial processes. Although the application of inhibitors can substantially prevent the corrosion of metallic substrates, their usage is not far from the limitations. Nowadays, due to the environmental hazards and toxicity of traditional inhibitors, green inhibitors are now replaced. Regarding the special position of plant extracts in the family of green inhibitors, attention should be paid to special features such as renewability and easy access. Undoubtedly, these capabilities have made plant extracts a practical class among all other types. Herein, the Rosemary extract is considered a golden candidate that can be employed as a green corrosion inhibitor in HCl media. The chemistry of Rosemary extract was estimated by Fourier-transform infrared (FT-IR), and Ultraviolet-visible (UV-Vis) spectroscopies. Afterward, the anti-corrosion performance of this inhibitor has been evaluated with electrochemical (potentiodynamic polarization and Electrochemical impedance spectroscopy (EIS)) and weight-loss tests. This study did not neglect the surface studies and the morphology of the surfaces was observed by FE-SEM and AFM techniques. Eventually, the adsorption mechanism has been predicted by thermodynamic studies and adsorption isotherms. Electrochemical outcomes demonstrated that mixed-type inhibition is responsible for 92% corrosion retardation during 6 h steel exposure to 1 M HCl media. The weight-loss studies also had a high convergence with the electrochemical studies and with a slight negligible difference, 800 ppm of rosemary extract prevented 87% of steel corrosion.

Performance evaluation and assessment of the corrosion inhibition mechanism of carbon steel in HCl medium by a new hydrazone compound: Insights from experimental, DFT and first-principles DFT simulations

In the present work, a new hydrazone compound, namely N'-[(Z)-(4-chlorophenyl)methylidene]-2-(5-methoxy-2-methyl-1H-indol-3-yl)acetohydrazide, noted HTH, was selected to protect carbon steel against corrosion in 1.0 mol/L HCl. Different chemical, electrochemical, and surface characterization techniques such as scanning electron microscope coupled with X-ray energy dispersion (SEM/EDX) were used to investigate the corrosion inhibition performance. Electrochemical data showed that the effectiveness of the inhibitor improved with increasing concentration, reaching 98% at the optimal concentration of 10-3 mol/L. The results of potentiodynamic polarization measurements showed that hydrazone acted as a mixed-type inhibitor. The EIS results showed an increase in polarization resistance accompanied by a noticeable decrease in Ceff,dl values. In the temperature range of 303 K-333 K, hydrazone protected carbon steel by 89%, showing high resistance to temperature effect. The analysis of the steel surface by SEM/EDX confirmed that the effectiveness of the hydrazone was attributed to the formation of a protective layer on the surface of the metal. Quantum chemical calculations revealed insights into the chemical reactivity of the tested hydrazone while first-principles density functional theory (DFT) and molecular dynamics (MD) simulation supported the experimental conclusions and showed outstanding adsorption ability of HTH on the Fe(110) surface. First-principles DFT simulations showed that the HTH molecule was more stable in a parallel adsorption mode.

Synthesis, experimental and computational studies on the anti-corrosion performance of substituted Schiff bases of 2-methoxybenzaldehyde for mild steel in HCl medium

Corrosion inhibition performance of two synthesized Schiff base ligands; (E)-2-((2-methoxybenzylidene)amino)phenol L1 and (E)-2-((4-methoxybenzylidene)amino)phenol L2 were carried out by weight loss measurement in 0.1 M hydrochloric acid (HCl) solution. Density Functional Theory (DFT) and Molecular dynamics (MD) simulation were applied to theoretically explain the inhibitors’ intrinsic properties and adsorption mechanism in the corrosion study. The result of the inhibition performances carried out at varying concentrations and temperatures were compared. The corrosion inhibition efficiencies of L1 and L2 at an optimal concentration of 10 × 10–4 M were 75% and 76%. Langmuir isotherm model fits the data obtained from the experiment with a correlation coefficient (R2) value closer to unity. The adsorption mechanism of inhibitor on the surface of the Fe metal occurred via chemisorption inferred from the Gibbs free energy (ΔGads). Scanning electron microscopy showed a mild degradation on the surface of the mild steel immersed in the L1, and L2 inhibited acid solution, which could be due to surface coverage. The energy dispersive X-ray spectroscopy showed the metal surface’s elemental composition and the existence of the chlorine peak, which emanates from the HCl medium. DFT calculations revealed that the hybrid B3LYP functional performed better than the M06-2X meta-functional in estimating the energies of the synthesized Schiff bases for corrosion inhibition as seen in the lower ΔE values of 3.86 eV and 3.81 eV for L1 and L2. The MD simulation revealed that the orientation of inhibitors on the surface of the metal resulted in the coordination bond formation and that the interaction energy of L2 was −746.84 kJ/mol compared to −743.74 kJ/mol of L1. The DFT and MD results agreed with the observed trend of the experimental findings.

Quantitative and qualitative analyses of grafted okra for corrosion inhibition of mild steel in acidic medium.

Introduction: Natural plant polymers demonstrate effective corrosion inhibition abilities, because of their numerous binding sites and excellent adsorption abilities. Methodology: In this study, the Box-Behnken method, gravimetric and electrochemical analyses were used to design and investigate the corrosion inhibition potential of a modified graft polymer of okra for mild steel in a 1M HCl medium. The influence of inhibitor concentration, temperature, and time were also investigated. Qualitatively, the Fourier Transform Infrared (FTIR) spectroscopy, Thermogravimetric Analysis (TGA), and Field emission scanning electron microscopy (FESEM) were used to characterize the extracts and evaluate the metal's surface morphology. Results and discussion: The quantitative analyses showed that the modified natural polymer's inhibition efficiency (IE) increased with concentration and reached 73.5% at 800ppm, with a mixed-type mode of inhibition. From the response surface methodology, it was revealed that temperature influences the IE more than concentration and immersion time. The optimized IE using the desirability function showed the possibility of attaining 88.2% inhibition with inhibitor concentration at 142.3ppm, temperature at 60.4°C, and an immersion time of 22.4h. The new functional groups in the hybrid polymer revealed by FTIR analysis shows that grafting improved the inhibitor's adsorption abilities. TGA analysis confirmed the extract's high thermal stability, which highlights the inhibitor's strong adsorption and efficiency for high temperatures. FESEM analysis indicated evidence of inhibitor adsorption onto the metal surface. Conclusion: These findings suggest that the grafting of okra with acrylamide enhances its inhibition properties and contributes to its functionality as a cost-effective plant-based alternative inhibitor against corrosion for mild steel facilities.

Enhanced adsorption of target branched compounds including antibiotic norfloxacin frameworks on mild steel surface for efficient protection: An experimental and molecular modelling study

In this study, an approach was proposed to employ new target branched compounds (TBCs) including multiple antibiotic norfloxacin frameworks for intensified adsorption films to achieve super protection of mild steel in HCl medium. Thus, the TBCs containing bis/tri norfloxacin skeletons were synthesized by multi-step preparation route. In addition, the reference linear compound (RLC) including a single norfloxacin part was also synthesized. The chemical structures of these compounds were confirmed by various means. It was demonstrated that the TBCs could form the tough adsorption films on the surface of mild steel, which could be processed mainly through chemisorption effect. The electrochemical analysis suggested that the TBCs displayed superior corrosion inhibition performance for low carbon steel in 1.0 mol·L−1 HCl solution over the RLC (RLC, 87.80%; TBC1, 97.63%; TBC2, 98.35%), which was further understood by the molecular modelling. The isotherm adsorption plots were employed to analyze the spontaneous adsorption process of the TBCs on low carbon steel surface, and a prominent chemisorption could be inferred by the standard Gibbs free energy changes of the adsorption.

Experimental and Theoretical Studies of the Corrosion Inhibition Performance of a Quaternary Phosphonium-Based Ionic Liquid for Mild Steel in HCl Medium

The corrosion inhibition performance of a quaternary phosphonium-based ionic liquid, i.e., hexadecyltriphenylphosphonium bromide (HPP), on mild steel in 1 M HCl solution was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) methods. The surface characterization of mild steel was examined by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). The results revealed that the inhibition efficiency increases with its increasing concentration, and it can reach up to 99.1% at the concentration of 0.07 mM HPP. PDP data showed that the absorption of HPP conformed to Langmuir adsorption, which served as a mixed-type inhibitor, involving chemisorption and physisorption. SEM analysis confirmed the formation of barrier film on the metal surface, inhibiting the acid attack. Moreover, density functional theory (DFT) calculations and molecular dynamics (MD) simulations were conducted to elucidate the adsorption mechanism of inhibitor molecules on the mild steel surface. A match between the experimental and theoretical findings was evidenced.

Evaluation of the corrosion inhibition of mild steel by newly synthesized imidazo[1,2-a]pyridine derivatives: experimental and theoretical investigation

In the pickling industry, corrosion can deteriorate the quality of equipment and supplies, causing financial losses and safety threats. Therefore, it has become crucial to develop novel corrosion inhibitors that are bioactive, efficient, affordable, medium-acid soluble, and ecologically safe to protect mild steel during industrial cleaning. In this work, three newly synthesized imidazo[1,2-a]pyridine derivatives were characterized by various spectroscopic techniques. The studied compounds were evaluated as corrosion inhibitors for mild steel in 1 M HCl medium using weight-loss, potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques. The imidazopyridine derivatives showed excellent anticorrosion performance, their inhibitory efficiencies increased with the increase of inhibitors concentration and evolved in the following order: Imd2 (98.1%) >Imd1 (96.5%) >Imd3 (95.3%). This order was justified by the presence of two chlorine atoms in the ortho position of the Imd2 structure. The three Imd derivatives obeyed to the Langmuir isotherm, this explained the formation of an organic monolayer on the steel surface indicated by the scanning electron microscope (SEM) and the atomic force microscope (AFM). In addition, density functional theory (DFT) and molecular dynamics (MD) simulations were performed to reveal the anticorrosion mechanism. The present study illustrates at the microscopic level how mild steel resists corrosion and ensures the safety of pickling.

Semi-Polycrystalline Polyaniline-Activated Carbon Composite for Supercapacitor Application.

We report on the synthesis of activated carbon-semi-polycrystalline polyaniline (SPani-AC) composite material using in-situ oxidative polymerization of aniline on the carbon surface in an aqueous HCl medium at an elevated temperature of 60 °C. The electroactive polymeric composite material exhibits a uniformly distributed spindle-shaped morphology in scanning electron microscopy (SEM) and well-defined crystallographic lattices in the high-resolution transmission electron microscopy (TEM) images. The X-ray diffraction (XRD) spectrum reveals sharp peaks characteristic of crystalline polyaniline. The characteristic chemical properties of polyaniline are recorded using laser Raman spectroscopy. The cyclic voltammetry curves exhibit features of surface-redox pseudocapacitance. The specific capacitance calculated for the material is 507 F g-1 at the scan rate of 10 mV s-1. The symmetrical two-electrodes device exhibits a specific capacitance of 45 F g-1 at a current density of 5 A g-1. The capacitive retention calculated was found to be 96% up to 4500 continuous charge-discharge cycles and observed to be gradually declining at the end of 10,000 cycles. On the other hand, Coulombic efficiency was observed to be retained up to 85% until 4500 continuous charge-discharge cycles which declines up to 72% at the end of 10,000 cycles. The article also presents a detailed description of material synthesis, the formation of polyaniline (Pani) chains, and the role of material architecture in the performance as surface redox supercapacitor electrode.

Experimental Study and Quantum Calculations for Spiramycin and Isosorbide Dinitrate as Corrosion Inhibitors

The investigation of the efficiency of two expired drugs, including Spiramycin and Isosorbide dinitrate, was done as corrosion inhibitors for aluminum in 0.1M HCl medium using the electrochemical method by Potentiostst at four temperatures (293, 303, 313, and 323 K) and 200 ppm as constant concentration for each drug. The results showed that these drugs gave good efficiencies equal to 98.836% and 94.285 % for Spiramycin and Isosorbide dinitrate at 293 K, respectively, by adsorption process on the metallic surface. They act as mixed-type inhibitors due to shifting corrosion potential either to active or noble direction. The corrosion data were measured and debated, where the corrosion current density was decreased after adding expired drugs to the corrosive medium due to inhibiting the cathodic and anodic reactions (i.e., the dissolution and reduction reactions). Using SEM exam, the inhibited surface of specimens was characterized to confirm the coverage of the surface by drug molecules. The adsorbed layer by Spiramycin was better than that by Isosorbide dinitrate. Also, the Fourier transform infrared spectra were used to limit the active site attracted to the surface by adsorption that confirmed the attraction by hydroxyl and nitro groups, as illustrated by the mechanism of inhibition. In addition, the antibacterial activity of the inhibitors against some types of bacteria was tested to confirm the formation of an inhibition zone against bacteria. The quantum chemical parameters exhibited a good correlation with the inhibition efficiency.

The kinetic and mechanistic study of levetiracetam oxidation with chloramine-B in acid medium

The medicine levetiracetam, marketed under the brand name Keppra, is approved by the Food and Drug Administration, used to treat seizures. It belongs to a class of drug known as anticonvulsants. The current work uses sodium-N-chloro-benzene sulfonamide or chloramine-B to evaluate the kinetics and mechanistic of levetiracetam at 308 K in HCl medium. (CAB). The reaction has a first-order dependence on [CAB]0 and [substrate]0, as well as a fractional-order dependence on the concentration of [HCl]. Changes in ionic strength or the adding of benzene sulfonamide have no effect on the rate. We looked at the effect at five temperatures. The Arrhenius plots were used to evaluate the thermodynamic parameters. The reaction stoichiometry was found 1:2, and chromatographic and spectroscopic studies anticipated the oxidation product imine. The probable mechanism back up the above-mentioned findings. The relevant rate law has been determined because of all these discoveries.

Study on the corrosion inhibition of biomass carbon quantum dot self- aggregation on Q235 steel in hydrochloric acid

At present, the development of efficient green corrosion inhibitors has become one of the important directions of metal corrosion protection. In this paper, biomass carbon quantum dots (BCQDs) were prepared by hydrothermal reaction using biomass precursors. The optical properties and structural composition of the synthesized BCQDs were characterized in detail. After that, the corrosion inhibition performance of BCQDs was evaluated by EIS, Tafel, SEM and TEM. The electrochemistry and surface tests demonstrate that the aggregates can effectively prevent Q235 steel from corrosion in 1 M HCl medium at 298 K-328 K, with the maximum inhibition efficiency of 94.1 % at the concentration of 200 mg/L at 308 K. Finally, the corrosion inhibition mechanism was analyzed by FTIR, CA and XPS on the surface of the corroded carbon steel samples. The inhibition mechanism suggests that BCQDs can inhibit metal corrosion by self-aggregation and adsorption on metal surface. This is owing to its small size effect and functional groups containing heteroatoms, easily forming dense protective film.