Application of the Kinetic-Thermodynamic Model for Inhibition of Acid Corrosion of Steel by Inhibitors Containing Sulfur and Nitrogen

Abstract

Corrosion inhibition characteristics of four selected Salkylisothioronium halides on steel in sulfuric acid (H 2 SO 4 ) media were investigated at 30°C, 40°C, 50°C, and 60°C. The number of active sites on the metal occupied by a molecule of the inhibitor (1/y) and the binding constants (K) of the inhibitor to the active sites were calculated at the different temperatures. Activation free energies, enthalpies, and entropies for the inhibition processes were determined from rate-constant data measured at 30°C, 40°C, 50°C, and 60°C at two fixed inhibitor concentrations. Data were compared and fitted to a published kinetic-thermodynamic model. Results were compared with fits obtained from application of Langmuir, Frumkin, and Flory-Huggins isotherms. Results also were correlated to the chemical structure of the inhibitors, the length of the alkyl chain of the cation, and the type of the anion.

Effect of benzamide on the corrosion inhibition of mild steel in sulphuric acid

“…19 In general, compounds of organic origin are known to have good corrosion inhibition characteristics for mild steel in acidic environments. [20][21][22][23][24][25] From this research work, benzamine as an organic compound can be considered as one of such compounds with very appreciable corrosion inhibition in strong acid like H 2 SO 4 even at low concentrations as obtained in this investigation. Benzamide can also be considered as an environmentally friendly inhibitor among many others that are currently receiving significant research attention in corrosion protection studies.…”

Guar Gum as Corrosion Inhibitor for Carbon Steel in Sulfuric Acid Solutions

“…However, the presence of halide ions in the solution such as the chloride may provoke pitting corrosion on the steel alloys. Some organic compounds have shown good inhibitor properties to protect steel against corrosion in acidic media * E-mail address: metwally552@hotmail.com [1][2][3][4][5][6][7]. The existing data show that those compounds act by a mechanism of adsorption on the metal surface.…”

“…The protection efficiency (P%) and the parameter (θ) that represents the weight of the metal surface covered by inhibitor molecules were calculated using the following equations: (2) where W free and W add , respectively, are the weight loss in the absence and the presence of inhibitor. The calculated values of P % and θ are listed in Table 1.…”

The Effect of Temperature and Acid Concentration on Corrosion of Low Carbon Steel in Hydrochloric Acid Media

“…3 is still satisfactory [3] . According to Grigorev et al [4,5] and Antropove and Suvgira [6] that they apply the transition state theory on the corrosion of steel in acids, they stated that the ratedetermining step for hydrogen evolution reaction is the recombination of adsorbed hydrogen to form hydrogen molecules. In acid-free, the Transition State of the rate determining recombination step represents a more orderly arrangement relative to the initial state and hence, negative value for the entropy of activation is obtained.…”