A comparative study of the corrosion inhibition of mild steel in sulphuric acid by 4,4-dimethyloxazolidine-2-thione (original) (raw)
Related papers
Journal of Molecular Structure, 2010
The corrosion inhibition characteristics of two synthesized Schiff bases, namely N, N´-bis(2-hydroxy-6-nitrobenzaldehyde) benzidine and N, N´-bis(salysylaldehyde) benzidine, on the mild steel corrosion in 2.0 M hydrochloric acid have been investigated by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy techniques. These studies were carried out at different concentrations, temperatures and durations. Polarization measurements indicate that the two inhibitors act as mixed type inhibitors. The adsorption of inhibitors obeys the Langmuir adsorption isotherm and the thermodynamic parameters (E a , K ads , ΔG 0 ads ) were calculated and discussed. Quantum chemical calculations were performed to provide further insight into the inhibition efficiencies determined experimentally.
Corrosion inhibition of mild steel in sulphuric acid using a bicyclic thiadiazolidine
The corrosion inhibition of mild steel in one normal sulphuric acid solution by tetra methyl ammonium bromide (TMAB) has been studied in relation to the concentration of the inhibitor as well as the temperature using electrochemical polarization (galvanostatic and potentiostatic polarizations) techniques. The results were supplemented with scanning electron microcopy and infra-red spectroscopy. All the methods employed are in reasonable agreement. There is no particular relationship of inhibition with concentration and temperatures. The thermodynamic functions of dissolution and adsorption processes were calculated from experimental polarization data and the interpretation of the results are given. Adsorption of TMAB was found to follow the Langmuir's adsorption isotherm. TMAB is a mixed type of inhibitor.
Imidazolidine-2-thione as corrosion inhibitor for mild steel in hydrochloric acid
2010
The inhibition effect of imidazolidine-2-thione (IMT) on the corrosion behaviour of mild steel (MS) in 1 N HCl was studied using potentiodynamic polarization, linear polarisation resistance (LPR), electrochemical impedance spectroscopy (EIS) and adsorption studies. The effects of inhibitor concentrations, temperature, corrosion rate and surface coverage are investigated. The corrosion rate and other parameters are evaluated for different inhibitor concentrations and the probable mechanism is also proposed. The results show that IMT possesses excellent inhibiting effect for the corrosion of the MS and the inhibitor acts as a mixed type inhibitor. The inhibitor does not affects the mechanism of the electrode processes and inhibits corrosion by blocking the reaction sites. The high inhibition efficiency of IMT was due to the adsorption of inhibitor molecules on the metal surface. The decrease of surface area available for electrode reactions to take place is due to the formation of a protective film. Activation energies and enthalpies of activation in the presence and absence of IMT were determined by measuring the temperature dependence of the corrosion current.
Journal of Central South University of Technology, 2010
The inhibition ability of 4-amino-5-phenyl-4H-1, 2, 4-trizole-3-thiol (APTT), ethylenediaminetetra-acetic acid (EDTA) and thiourea (TU) for mild steel corrosion in 1.0 mol/L HCl solution at 30 °C was investigated. Tafel polarization and electrochemical impedance spectroscopy (EIS) were used to investigate the influence of these organic compounds as corrosion inhibitors of mild steel in 1.0 mol/L HCl solution at 30 °C. The inhibition mechanism was discussed in terms of Langmuir isotherm model. Results obtained from Tafel polarization and impedance measurements are in a good agreement. The inhibition efficiency increases with the increase of the inhibitor concentration. The adsorption of the inhibitors on the mild steel surface follows Langmuir adsorption isotherm and the free energy of adsorption ΔG ads indicates that the adsorption of APTT, EDTA, and TU molecules is a spontaneous process and a typical chemisorption.
Investigation of some oleochemicals as green inhibitors on mild steel corrosion in sulfuric acid
Journal of Applied Electrochemistry, 2009
The inhibitive effect of four oleo chemicals (namely; 2-Pentadecyl-1,3-imidazoline (PDI), 2-Undecyl-1,3-imidazoline (UDI), 2-Heptadecyl-1,3-imidazoline (HDI), 2-Nonyl-1,3-imidazoline (NI)), regarded as green inhibitors, were studied for the corrosion protection of mild steel in 0.5 M H2SO4. The methods employed were weight loss, potentiodynamic polarization and electrochemical impedance techniques. Scanning electron microscopy (SEM) was carried out on the inhibited and uninhibited metal samples to characterize the surface. The purity of synthesized inhibitors was checked by FT-IR and NMR studies. The inhibition efficiency increased with increase in inhibitor concentration, immersion time and decreased with increase in solution temperature. No significant change in IE values was observed with increase in acid concentration. The best performance was obtained for UDI possessing 96.2% inhibition efficiency at 500 ppm concentration. The adsorption of the compounds on the mild steel surface in the presence of sulfuric acid obeyed Langmuir’s adsorption isotherm. The values obtained for free energy of adsorption and heats of adsorption suggest physical adsorption. The addition of inhibitor decreased the entropy of activation suggesting that the inhibitors are more orderly arranged along the mild steel surface. The potentiodynamic polarization data indicate mixed control. The electrochemical impedance study further confirms the formation of a protective layer on the mild steel surface through the inhibitor adsorption.
Corrosion Science, 2010
4-(pyridin-2yl)-N-p-tolylpiperazine-1-carboxamide(PTC) was synthesized and characterized using FT-IR, 1 H NMR, and 13 C NMR spectra. The inhibitive action of 4-(pyridin-2yl)-N-p-tolylpiperazine-1carboxamide(PTC) against corrosion of mild steel in a 1M HCl solution was investigated using weight loss measurements, potentiodynamic polarization and electrochemical impedance spectroscopy(EIS). The inhibition efficiency increases with increasing concentration of inhibitor whereas it decreases with increasing temperature. EIS results showed that the change in the impedance parameters (Rct and Cdl) with concentration of (PTC) is indicative of the adsorption of molecules leading to the formation of a protective layer on the surface of mild steel. Potentiodynamic polarization study showed that PTC is a mixed type inhibitor. Surface analysis by SEM confirmed the formation of adsorbed protective layer of the inhibitor on the steel surface. The adsorption of inhibitor follows the Langmuir adsorption isotherms. Thermodynamic parameters such as activation energy (Ea), free energy change (ΔGads), enthalpy change (ΔHads) and entropy change (ΔSads) were also calculated and discussed in detail.
Journal of the Taiwan Institute of Chemical Engineers, 2012
Mild steel is widely applied as construction material in many industries due to its exceptional mechanical properties and low cost. The main problem of applying mild steel is its dissolution in acidic solutions. Recently, the inhibition of mild steel corrosion in acid solutions by different types of organic inhibitors has been extensively studied [1-6]. The use of inhibitors is the most economical and practical method of reducing corrosive attack on metals [7-9]. During the past decade, the inhibition of mild steel corrosion in acid solutions by various types of organic inhibitors has attracted much attention [10,11]. There is a continuing effort to find a corrosion inhibitor that exhibits greater effect with smaller quantity in the corrosion medium. This is a challenging problem in the steel industry because corrosion over mild steel surfaces affects long term industrial projects. The performance of the corrosion inhibitors based on organic compounds containing nitrogen, sulphur and oxygen atoms shows promising results. The inhibitors influence the kinetics of the electrochemical reactions which constitute the corrosion process and thereby modify the metal dissolution in acids. The existing data show that most organic inhibitors act by adsorption on the metal surface. They change the structure of the electrical double layer by adsorption on the metal surface The choice of N,N 0-[(methylimino)dimethylidyne]di-2,4-xylidine (MIDX) as corrosion inhibitor for mild steel is based on the following considerations: (a) MIDX is a relatively cheap material, (b) commercially available, (c) contain 5 5N-N-N5 5 group, aromatic ring as active centres and (d) its highly soluble in acidic media. This article therefore reports the use of electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, weight loss, atomic force microscopy (AFM) and scanning electron microscopy (SEM) to investigate the corrosion inhibition and adsorption characteristics of N,N 0-[(methylimino)dimethylidyne]di-2,4-xylidine on the mild steel surface in acidic medium. The LD 50 dose of N,N 0-[(methylimino)dimethylidyne]di-2,4-xylidine (MIDX) 10 mg kg À1 in rats [12] The structure of MIDX is shown in Fig. 1. 2. Experimental 2.1. Inhibitor The studied compound, N,N 0-[(methylimino)dimethylidyne]di-2,4-xylidine, an acaricide, is available under the brand name Bumetran*. Stock solution of MIDX was made in 10:1 ratio of water:ethanol mixture to ensure solubility. This stock solution was used for all experimental purposes.
Inhibition of mild steel corrosion in sulfuric acid solution by thiadiazoles
2006
The inhibitive effect of hydroxyethyl cellulose (HEC) on mild steel corrosion in aerated 0.5 M H 2 SO 4 solution was studied using gravimetric and electrochemical techniques. The effect of temperature on corrosion and inhibition was also investigated. The results show that hydroxyethyl cellulose functioned as a good inhibitor in the studied environment and inhibition efficiency increased with concentration of inhibitor. Potentiodynamic polarization measurements revealed that HEC inhibited both the cathodic and anodic partial reactions of the corrosion processes. Impedance results clearly show that HEC inhibited the corrosion reaction by adsorption onto the metal=solution interface by significantly decreasing the double layer capacitance (C dl ). This result was greatly pronounced in the presence of the inhibitor system (HEC þ KI) that contains halide additive. Temperature studies revealed an increase in inhibition efficiency with rise in temperature. The adsorption behavior was found to obey the Freundlich isotherm. The values of activation energy, heat of adsorption, and standard free energy suggest that there was transition from physical to chemical adsorption mechanism of HEC on the mild steel surface. Quantum chemical calculations using the density functional theory (DFT) was employed to determine the relationship between molecular structure and inhibition efficiency.
Development of new corrosion inhibitor tested on mild steel supported by electrochemical study
Results in Physics, 2018
Mild steel is a metal which is commonly used in industrials and manufacturing of equipment for most industries round the world. It is cheaper cost compared with the other metals and its durable, hard and easy-to-wear physical properties make it a major choice in the manufacture of equipment parts. The main problem through the uses of mild steel in industry is its resistance against corrosion, especially in acidic solutions. This case led to raise the cost of maintenance of equipment that used mild steel and as a result increased costs for the company. Organic corrosive inhibitors that also act as green chemicals, 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazolhave been synthesized. This inhibitor is tested as corrosion inhibitor on a mild steel sample MS in 1M hydrochloric acid solution (HCl) using electrochemical measurements test includes PD (Potentiodynamic), EIS (Electrochemical impedance spectroscopy), OCP (Open circuit potential) and EFM (electrochemical frequency modulation). The obtained results indicate that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol acts as a good corrosion inhibitor for mild steel sample in HCl solution with efficiency above 90%. Changes in the impedance parameters postulated adsorption on the mild steel specimens' surfaces of, which it going to the formation of protective coating layer. It also shows that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazolcorrosion inhibitors are 2 effective in helping to reduce and slow down the corrosion process that occurs on mild steel surface in hydrochloric acid solution. Increase of corrosion inhibitor concentration provides a protective layer of mild steel. However, this protective layer becomes weak when the temperature of the solution increases.