Evaluation of an aza dipyrromethene derivative as a green corrosion inhibitor via experimental and theoretical methods

1,7-dihydroxy-aza-dipyrromethene (DAD) was utilized as an eco-friendly corrosion inhibitor against highly acidic media on a mild steel surface. Weight loss, potentiodynamic polarization measurements, and electrochemical impedance spectroscopy were applied to investigate the inhibition mechanism at a temperature range of 298-328 K. The surface morphology of the metallic surface was monitored using the scanning electron microscopy (SEM) technique. Weight loss and electrochemical measurements revealed that DAD demonstrates good inhibition performance (inhibition efficiency: 79-83 %) against highly acidic media as a mixed-type inhibitor. Global reactivity parameters, Fukui functions, and stabilization energies (E(2)) were calculated to discuss potential local electron donor sites.

Automated summary

In this study, 1,7-dihydroxy-aza-dipyrromethene (DAD) was used as a corrosion inhibitor for mild steel in highly acidic media. The results showed that DAD exhibited good inhibition performance as a mixed-type inhibitor. The inhibition mechanism of DAD was discussed by calculating global reactivity parameters and stabilization energies.