Document Details

Document Type : Article In Journal 
Document Title :
Effect of temperature on the inhibition of the acid corrosion of steel by benzimidazole derivatives
Effect of temperature on the inhibition of the acid corrosion of steel by benzimidazole derivatives
 
Subject : Chemistry 
Document Language : English 
Abstract : The effect of 2-mercaptobenzimidazole (inh. I) and 2-mercapto-5- methylbenzimidazole (inh. II) on the corrosion of mild steel in 1M solutions of sulphuric acid has been investigated in relation to the concentration of the inhibitor as well as temperature by various monitoring corrosion techniques. The results obtained revealed that these compounds are good inhibitors. All the impedance diagrams gave semicircles for both inhibitors indicating that the corrosion of mild steel is controlled by a charge transfer process and the presence of either inhibitor does not alter the mechanism of the dissolution of mild steel. In general, both inhibitors efficiencies increased with increasing the inhibitors concentration at all temperatures used. On the other hand, inhibitors efficiencies were almost constant with increasing the temperature at concentrations 5 × 10-4 M, 1 × 10-3 M and 5 × 10-3 M. The best performance was noticed in case of (inh. II) especially at the concentration 5 × 10-3 M. Adsorption of both inhibitors was found to follow Langmuir, Flory-Huggins isotherms and kinetic-thermodynamic model. The binding constants "K" were calculated for both inhibitors. On increasing the temperature, the value of "K" increased in both cases indicative of stronger binding of the inhibitor molecule to the mild steel surface and hence higher inhibition efficiency at higher temperatures. The activation energy of the corrosion reaction decreases with increasing the concentration of (inh. I) or (inh. II). The adsorption of both inhibitors on the surface of mild steel is probably chemisorbed on the electrode surface. The thermodynamic parameters were calculated. Mass loss measurements revealed that both inhibitors exhibit maximum inhibition efficiency with increasing the concentration and temperature which confirm the data obtained from AC impedance. DC polarization data reveals that, both inhibitors does not alter the mechanism of anodic behaviour of mild steel and they behave as mixed type inhibitors. Again both inhibitors exhibit maximum inhibition efficiency with increasing the concentration and temperature which confirm the data obtained from AC impedance. 
ISSN : 0033-1732 
Journal Name : Protection of Metals and Physical Chemistry of Surfaces 
Volume : 47 
Issue Number : 3 
Publishing Year : 1432 AH
2011 AD 
Article Type : Article 
Added Date : Sunday, June 10, 2012 

Researchers

Researcher Name (Arabic)Researcher Name (English)Researcher TypeDr GradeEmail
فاطمة محمد محجوبMahgoub, Fatma MResearcherDoctorateftm_mahgoub@yahoo.com
فوزية محمد النويصرAl-Nowaiser, Fawziya MResearcherDoctoratefalnowaiser@kau.edu.sa
أمل مساعد السديريAl-Sudairi, Amal MResearcherMaster 

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