Study on corrosion inhibition of a ternary complex inhibitor composed of o-toluenesulfonamide
In order to develop a low toxicity and high efficiency corrosion inhibitor with less dosage and high efficiency,the corrosion inhibition effect of a ternary corrosion inhibitor composed of o-tolu-enesulfonamide(OTS),potassium iodide(KI)and cetyltrimethyl ammonium bromide(CTAB)in 0.5 mol·L-1 sulfuric acid solution was studied by weight loss method,electrochemistry and scanning electron microscopy(SEM).The optimal concentration ratio of the ternary corrosion inhibitor was OTS∶KI∶CTAB=15∶6∶5,and the corrosion inhibition efficiency reached 98.18%with the total concentration of 130 mg·L-1.The activation energy of corrosion process increased after the addition of ternary corrosion inhibitor,indicating that the corrosion reaction was more difficult to occur.The ternary corrosion inhibitor conformed to the Langmuir adsorption isothermal formula,and the adsorp-tion on the surface of carbon steel was a spontaneous weak chemical adsorption process.The corrosion inhibition efficiencies calculated by polarization curve method and electrochemical impedance method were consistent with that by weight loss method.The polarization curve showed that the ternary corrosion inhibitor was a mixed type corrosion inhibitor which mainly inhibited anode reaction.SEM microscopic appearance showed that there was almost no corrosion trace on the surface of carbon steel after the addition of ternary corrosion inhibitor,indicating that there was a synergistic effect of corro-sion inhibition between ternary corrosion inhibitor molecules,forming a dense and firm protective film.
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