Corrosion inhibition of carbon steel by tetraglycidyloxy deoxy-D-glucose epoxy resin in hydrochloric acid: experimental and computational insights

초록

This work explores the protection performance of tetraglycidyloxy deoxy-D-glucose (TGDG) epoxy resin for carbon steel in 1 M HCl by the experimental and theoretical approaches. Potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) revealed that TGDG acts as a highly efficient, concentration-dependent inhibitor, achieving a maximum inhibition efficiency of 91.55% at 10(-)(3) M, with corrosion current density reduced from 886.125 to 83.729 mu A/cm(2). EIS results corroborated these findings, showing a substantial increase in charge transfer resistance (from 33.47 to 199.4 Omega<middle dot>cm(2)) and a decrease in double-layer capacitance (from 310 to 108 mu F). Temperature effect studies indicated a moderate decline in efficiency at elevated temperatures, maintaining 59.68% inhibition at 328 K. Thermodynamic evaluations showed an increase in activation energy (from 21 to 59.67 kJ/mol) and enthalpy (from 18.19 to 57.08 kJ/mol), while a decrease in entropy, suggesting a more ordered inhibitor-metal interface. Adsorption followed the Langmuir isotherm (R-2 = 1), indicating monolayer, spontaneous adsorption with Delta G(ads) = - 44.47 kJ/mol. DFT calculations revealed favorable electronic properties for both neutral and protonated TGDG, while MC/MD simulations demonstrated strong adsorption energies (-232.75 kcal/mol for TGDG) and chemical interaction at < 3.5 & Aring; distances. SEM/EDS analyses confirmed smoother metal surfaces and reduced corrosive element content post-inhibition. These findings collectively highlight TGDG's promise as an effective, thermally stable, and surface-active green inhibitor for carbon steel protection in acidic environments.

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