Corrosion Of Mild Steel In H2SO4 Research Articles

Study of mild steel corrosion in H2SO4: effect of sulfate ion addition

RESUMO A compreensão dos fenômenos envolvidos na corrosão do aço carbono em meio H2SO4 é de fundamental importância, visto que este é o principal produto da indústria química. Contudo, poucos trabalhos recentes relacionados a corrosão do aço carbono em H2SO4 em diferentes concentrações de sulfato são reportados. O presente trabalho objetivou estudar a corrosão do aço carbono em H2SO4 1 mol L–1 sob incremento de íons SO42– de origem salina. Medidas de potencial a circuito aberto, ensaios de imersão com perda de massa, quantificação do teor de íons ferro total em solução e curvas de polarização potenciodinâmica foram realizadas e sugerem que a corrosão do aço carbono em H2SO4 com adição de sulfato ocorre por mecanismo de dissolução-passivação, sendo influenciada pela concentração de sulfato adicionado. Micrografias da superfície do aço carbono denotam que a corrosão ocorre de maneira uniforme e com a formação de produtos de corrosão insolúveis distribuídos não homogeneamente na superfície metálica. Tais produtos estão provavelmente associados à precipitação de FeSO4 e/ou Fe(OH)3 na superfície.

Synergistic Inhibition Effect of 3-Carboxypyridine and Potassium Iodide on Mild Steel Corrosion in H2SO4: Electrochemical and Surface Analyses

Synergistic Inhibition Effect of 3-Carboxypyridine and Potassium Iodide on Mild Steel Corrosion in H2SO4: Electrochemical and Surface Analyses

Adsorptive and Anticorrosive Studies of Guar Gum and Halides with Mild Steel in Acidic Medium

The inhibitory effect of guar gum (GG) as a green inhibitor has been studied using a variety of methodologies, including weight loss, thermometric studies at 30-60 ºC. The potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron micrographs have been found to the good inhibitor for mild steel corrosion in H2SO4 (pH = 1) medium. Guar gum fits to the Langmuir adsorption isotherm when it adsorbs to metal surfaces. It has also been investigated how adding halides (KCl, KBr and KI) will affect the process. The findings demonstrated that guar gum concentration increased with inhibition efficiency (I%). All of the concentrations of guar gum are shown to be promoted by the inhibitive impact of guar gum in addition to halide ions. The trend Cl– < Br– < I– has been seen to improve inhibition efficiency (I%) and the extent of surface coverage (θ), which suggests that the electronegativity and radii of the halide ions play a significant role in the adsorption process. According to polarization curves, guar gum functions as a mixed-type inhibitor. The outcomes of gravimetric studies and electrochemical procedures were in good agreement. Based on thermodynamic characteristics and a comparison of the FT-IR spectra of pure and metal surface product, a thorough adsorption of the inhibitor molecules on the mild steel surface was proposed. When the synergism parameter (SI) was analyzed, it is found to be greater than unity, indicating that synergism alone is responsible for the increased inhibitory efficiency caused by the addition of halides.

Comparative study of synergistic inhibition of mild steel and pure iron by 1-hexadecylpyridinium chloride and bromide ions

The comparison of the corrosion behavior of mild steel (MS) and pure iron (PI), and synergistic action of 1-Hexadecylpyridinium chloride (HDPCl) and Br− ion are studied in 0.5 M sulphuric acid solution. The study was carried out using open-circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy measurements. In absence of inhibitor (blank), the corrosion rate of mild steel is greater than that of pure iron. In presence of HDPCl only, the inhibition efficiency for MS corrosion in H2SO4 is higher than that of PI and attributed to the different surface charges on both MS and PI in H2SO4 solution. The obtained results indicate that the inhibition efficiency (ηi%) of HDPCl is significantly increased in the presence of Br− ions for both MS and PI. In the presence of the Br− ions, the ηi increases significantly at relatively low concentrations of HDPCl ([HDPCl] = 8 × 10-6 M), i.e, ηi is 96 and 99% for MS and PI, respectively. The synergism factor (Sθ) is found to be more than unity suggesting greater ηi due to the addition of Br− ions to the HDPCl with a co-operative adsorption action. Chemisorption is postulated as the mode of adsorption based on extracted thermodynamic parameters.

Inhibition of Steel Corrosion in Sulfuric Acid Solution by 1,10-Phenanthroline, para-Aminobenzoate and their Corresponding Manganese Complex

Abstract The ligands 1,10-phenanthroline, (P) and para-aminobenzoate, (B); as well as their corresponding MnPB complex [bis-(dimanganese di-μ-paraaminobenzoate dichloro diphenanthroline)] have been investigated as inhibitors of mild steel corrosion in H2SO4 (0.5 M) solutions via potentiodynamic and electrochemical impedance spectroscopy techniques. Stability of the prepared complex was examined by UV-visible spectroscopy. The corrosion inhibition, thermodynamics, and adsorptive properties obtained have shown that MnPB complex has remarkable effects in the acidic solutions. Theoretical fitting of different adsorption isotherms such as Langmuir, Flory–Huggins, and the kinetic-thermodynamic models were tested and the thermodynamic activation parameters were calculated. The data revealed that the corrosion inhibition mechanism of mild steel in acidic solutions by the MnPB complex goes via physicochemical adsorption.

Experimental and theoretical investigations of a newly synthesized azomethine compound as inhibitor for mild steel corrosion in aggressive media: A comprehensive study

A new azomethine compound viz. 3-(2-amino-4,5-dimethylphenyl)imino)methyl) benzaldehyde (ADMB) was synthesized following a greener approach at room temperature and its anti-corrosion characteristics for mild steel (MS) corrosion were examined at various temperatures (298K to 328K) and concentrations (1mM to 0.001mM) in 0.5M H2SO4 via electrochemical methods allied with surface characterization techniques. The adsorption of the ADMB molecules on the metal surface follows Langmuir's adsorption isotherm. To ascertain the mode of adsorption process, various adsorption and activation parameters were evaluated. Surface characterization studies viz. ATR-FTIR, SEM, AFM and EDS depict the formation of protective layer of ADMB on MS specimen. Density functional theory (DFT) treatment of ADMB established that the lower energy gap (ΔE) between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) resulted in significantly high inhibition efficiency. These results have shown that ADMB act as an effective inhibitor for MS corrosion in H2SO4. The inhibition efficiencies predicted from experimental measurements are in agreement with the theoretically evaluated parameters and results of spectroscopic techniques.

Novel synthesized Schiff Base-based cationic gemini surfactants: Electrochemical investigation, theoretical modeling and applicability as biodegradable inhibitors for mild steel against acidic corrosion

Three novel Schiff base compounds were synthesized and characterized using spectroscopic methods (FT-IR, 1H NMR and 13C NMR). Their critical micelle concentrations were determined by conductimetric and surface tension measurements. The inhibition potentials of the prepared surfactants on mild steel corrosion in H2SO4 have been investigated using electrochemical and scanning electron microscopy techniques. The results showed that all surfactants are good inhibitors for mild steel corrosion with the percentage inhibition efficiency of up to 99.21% at 1.0mM. The data showed that the studied surfactants are mixed-type inhibitors. Adsorption of the inhibitors obeyed the Langmuir isotherm. The results obtained from theoretical calculations support our experimental studies.

Controlling the Rate of Dissolution of Mild Steel in Sulfuric Acid Through the Adsorption and Inhibition Characteristics of (4-(4-Hydroxybenzylideneamino)-4H-1,2,4-Triazole-3,5-diyl)dimethanol (HATD)

Inhibition of mild steel corrosion in H2SO4 using a Schiff’s base derived from 1,2,4-triazole, (4-(4-hydroxybenzylideneamino)-4H-1,2,4-triazole-3,5-diyl) dimethanol, has been investigated by weight loss, electrochemical, surface morphological, adsorption, and quantum chemical studies. It is found that inhibition efficiency increases with concentration of inhibitor and decreases with temperature. Results of polarization studies revealed the mixed type behavior of the inhibitor. Adsorption phenomenon follows Langmuir isotherm model, and values of free energy changes indicate that the mechanism involves both physisorption and chemisorption. Values of activation parameters revealed the endothermic nature of the corrosion process. Surface morphological studies support the prediction of the protection of metal by the formation of a surface film in the presence of the inhibitor. Geometry optimization of the inhibitor molecule is done by quantum chemical studies.

Inhibitive action of Carica papaya extracts on the corrosion of mild steel in acidic media and their adsorption characteristics

PurposeTo evaluate the effect of different parts of Carica papaya (leaves (LV), seeds (SD), heart wood (HW) and bark (BK)) as eco‐friendly and non‐toxic mild‐steel corrosion inhibitors in H2SO4 at 30 to 60 oC.Design/methodology/approachAcid extracts of the different parts of Carica papaya were used as inhibitors in various corrosion tests. Gravimetric and gasometric techniques were used to characterise the mechanism of inhibition.FindingsThe LV, SD, HW and BK extracts were found to inhibit mild steel corrosion in H2SO4. The inhibition efficiencies of the plant's part extracts follow the trend: LV > SD > HW > BK. Inhibition efficiency increased with extracts concentration but decreased with temperature. Physical adsorption of the phytochemical components of the plant on the metal surface is proposed as the mechanism of inhibition. The experimental data fits well into the Langmuir and Temkin adsorption isotherms.Practical implicationsThe plant extracts can be used in chemical cleaning and picking processes.Originality/valueThe research provides information on the possible use of the different parts of Carica papaya as sources of cheap eco‐friendly and non‐toxic corrosion inhibitors.