Adsorption mechanism of 3-(1,4-disubstituted-1,2,3-triazolyl) uridine nucleosides against the corrosion of mild steel in HCl

Abstract

To date, the corrosion of metal surfaces is one of challenging problems in the modern business (technology and industrial applications). So, corrosion control of metal at different stage of application is necessary. To avoid this problem, organic and inorganic corrosion inhibitors are widely used. For this purpose, the present study deals with the corrosion inhibition assessment of novel uridine- (Murmu et al., 2020; Dehghani et al., 2020; Li et al., 2020) [1,2,3]triazole nucleosides as green corrosion inhibitors, namely 2-(acetoxymethyl)-6-(4-((3-(3,4-diacetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-2,6-dioxo-3,6-dihydropyrimidin-1(2H)-yl)methyl)-1H-1,2,3-triazol-1-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (TPTAc) and 2-(acetoxymethyl)-5-(3-((1-(3,4-diacetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-1H-1,2,3-triazol-4-yl)methyl)-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)tetrahydrofuran-3,4-diyl diacetate (TPDAc). After synthesis and characterization procedure, the corrosion inhibition performances of these compounds against the corrosion of mild steel (MS) are studied using both experimental and theoretical exploration. The effect and inhibition action of these inhibitors on the electrochemical behavior of MS corrosion was evaluated experimentally via electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and weight loss techniques. In addition, theoretical calculations are made to analyze adsorption properties and characteristics of synthesized molecules on MS surface. The results obtained from all electrochemical experiments confirmed that the inhibitors understudy exhibited high inhibition performances thanks to their adsorption capacity on MS surface. EIS data indicated that TPTAc is quite effective at 5 × 10−3 M than TPDAc at the same concentration. PDP results revealed that the studied molecules acted as mixed-type inhibitors and they had a strong influence on the protective layer formed. The corrosion rate (CR) values considerably fall down from 1.135 mg cm−2 h−1 to 0.090 and 0.158 mg cm−2 h−1 at 5 × 10−3 M of TPTAC and TPDAc, respectively. Moreover, the effect of KI ions was also evaluated, and the results suggest that the presence of iodide ions has significantly improved the inhibition performances (97% for TPTAc and 90% for TPDAc at 5 × 10−3 M). Also, the calculated values of Gibb's free energy ( ΔGads0) are −33.61 kJ/mol and −34.33 kJ/mol for TPTAC and TPDAc, respectively; lying between −21 and −40 kJ/mol, confirming both physisorption as well as chemisorption interactions. In addition, results indicated that the inhibition intensity of studied compounds was expected to happen by means of adsorption over the MS surface which obeys the Langmuir's adsorption isotherm. The surface characterizations confirmed previous findings and contributed additional evidence on the morphological changes of MS surface during corrosion. The anti-corrosive and adsorption properties of studied compounds were detailed by DFT and molecular dynamics (MD) simulations. The results of theoretical calculations demonstrate strong and consistent agreement with experimental outcomes.