The Research Of Corrosion Inhibition Properties For Imidazoles

Metal corrosion has costed our society hugely.It is not necessary to use large size equipments during the process of using corrosion inhibitors to protect metal from corrupting,and it will not cause any actual effects on metal materials.Also it is cheaper to use corrosion inhibitors compared with other corrosion preventing methods.The most used corrosion inhibitors nowadays are organic ones.These organic compounds contain unmatched heteroatom and large π bound which helps the inhibitor molecular to interact with the empty d orbit on the surface of carbon steel for further forming the protection membrane to prevent corrosion from happening.At present stage,the medical molecular has received wide attention from researchers since it contains large amounts of heteroatom.Simultaneously,using abandoned medical materials as corrosion inhibitors will contributes to environmental protection and maximal utilization of resources.In this article,we adopt four kinds of imidazole derivatives as research objects which are flubendazole,mebendazole,thiabendazole and albendazole.We use 1 M HNO₃ as corrosion inhibitor and low-carbon steel as the metal to be corroded.We study the corrosion-preventing rate,absorption mechanism and the corresponding corrosion mechanism of these four kinds through the weightlessness experiment,polarization curves method and quantum chemical calculation method.The results of weightlessness experiments show that when using 1 M HNO₃ as corrosion material,these four kinds of medical molecules can relatively prevent corrosion of low-carbon steel.The corrosion-preventing rate reduces along with the rising of temperature and with the increasing of concentration of corrosion inhibitors.The corrosion-preventing rate of the four kinds reach maximum when the temperature is 25℃ and concentration is 5 mM.The maximum corrosion-preventing rate of these four kinds are 96.I%,92%,90.2%,87.5%.Among these four kinds,flubendazole works best as corrosion inhibitor.At the same time,the molecular absorptions of these four corrosion inhibitors all submit to the langmuir absorption isotherm,and their absorption are mainly physical ones.The polarization curve presents that these four corrosion inhibitors belong to compound inhibitors,and flubendazole is the one with the best corrosion preventing property among these four based on analysis of electrochemical parameters.We can conclude that flubendazole works the best as corrosion inhibitor by analyzing quantum chemical parameters and Fukui index,also flubendazole has the most active spots.