Porphyrins as Corrosion Inhibitors for N80 Steel in 3.5% NaCl Solution: Electrochemical, Quantum Chemical, QSAR and Monte Carlo Simulations Studies

Molecules

Ambrish Singh⁴  Yuanhua Lin⁴  Mumtaz A. Quraishi⁵  Lukman O. Olasunkanmi³  Omolola E. Fayemi¹  Yesudass Sasikumar¹  Baskar Ramaganthan¹  Indra Bahadur¹  Ime B. Obot²  Abolanle S. Adekunle³  Mwadham M. Kabanda¹  Eno E. Ebenso¹ 

[1] Department of Chemistry, School of Mathematical & Physical Sciences, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa; E-Mails:;Center of Research Excellence in Corrosion, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia; E-Mail:;Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife 220005, Nigeria; E-Mails:;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan, China; E-Mails:;Department of Chemistry, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India; E-Mail:

关键词: N80 steel;    EIS;    polarization;    porphyrins;    SECM;    SEM;    QSAR;    Monte Carlo simulations;    quantum chemical studies;   

DOI  :  10.3390/molecules200815122

来源: mdpi

【 摘 要 】

The inhibition of the corrosion of N80 steel in 3.5 wt. % NaCl solution saturated with CO₂ by four porphyrins, namely 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphyrin (HPTB), 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphyrin (T4PP), 4,4′,4″,4‴-(porphyrin-5,10,15,20-tetrayl)tetrakis(benzoic acid) (THP) and 5,10,15,20-tetraphenyl-21H,23H-porphyrin (TPP) was studied using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, scanning electrochemical microscopy (SECM) and scanning electron microscopy (SEM) techniques. The results showed that the inhibition efficiency, η% increases with increasing concentration of the inhibitors. The EIS results revealed that the N80 steel surface with adsorbed porphyrins exhibited non-ideal capacitive behaviour with reduced charge transfer activity. Potentiodynamic polarization measurements indicated that the studied porphyrins acted as mixed type inhibitors. The SECM results confirmed the adsorption of the porphyrins on N80 steel thereby forming a relatively insulated surface. The SEM also confirmed the formation of protective films of the porphyrins on N80 steel surface thereby protecting the surface from direct acid attack. Quantum chemical calculations, quantitative structure activity relationship (QSAR) were also carried out on the studied porphyrins and the results showed that the corrosion inhibition performances of the porphyrins could be related to their E_HOMO, E_LUMO, ω, and μ values. Monte Carlo simulation studies showed that THP has the highest adsorption energy, while T4PP has the least adsorption energy in agreement with the values of σ from quantum chemical calculations.

【 授权许可】

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