Intercalation of 1,2,4-triazole in methanol modified-kaolinite: Application for copper corrosion inhibition in concentrated sodium chloride aqueous solution

Abstract

New hybrid kaolinite was obtained for the first time by intercalation of 1,2,4-triazole (TAZ) in the interlayer space of methoxykaolinite. The successful synthesis of the material (K-TAZ) was fully confirmed by XRD, FTIR, and solid state 13C NMR spectroscopy characterizations. Thermogravimetric analysis of K-TAZ confirmed the quantitative intercalation of TAZ and allowed the determination of the chemical formula of the nanohybrid material (Si2Al2O5(OH)3,72(OCH3)0,28(TAZ)0,50(H2O)0,17(CH3CH2OH)0,06). The material was subsequently used as copper corrosion inhibitor in a concentrated NaCl aqueous solution (0.5 ​M), TAZ being well-known as copper corrosion inhibitor. K-TAZ behaves like a mixed inhibitor (cathodic and anodic) with an inhibition efficiency reaching 96.9% when an inhibitor concentration of 320 ​mg ​L−1 was used. The study of the role played by different constituents of K-TAZ on metal protection showed that the cathodic inhibition was mainly due to free methoxykaolinite particles while the de-intercalated TAZ molecules provides the anodic protection. Thermodynamic studies of the process revealed that K-TAZ protects the copper by reinforcing (through physical adsorption) the protective layer made of copper oxide and chlorides produced when the metal react with the corrosive sodium chloride solution. This work clearly demonstrates the potential use of kaolinite for the enhancement of the efficiency of some selected metal corrosion inhibitors.