Development of pH-sensitive chitosan/plant extract microcapsules: Enhanced corrosion protection for carbon steel in HCl solution

Abstract

In recent years, controlled-release green corrosion inhibitors have become a research hotspot in the field of corrosion. In this study, chitosan/plant extract microcapsules (GCI@CS) loaded with Ambrosia artemisiifolia extract (green corrosion inhibitor, GCI) were prepared by emulsification cross-linking. Both the functional groups and micromorphology of GCI@CS were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and optical microscopy (OM). The loading capacity and encapsulation efficiency of GCI@CS were analyzed using UV–Vis spectroscopy. The corrosion inhibition performance of GCI@CS on carbon steel (C-steel) in 1.0 mol/L HCl was investigated using electrochemical impedance spectroscopy (EIS). The results indicated that GCI@CS, as a pH-sensitive microcapsule, can provide effective corrosion protection for C-steel in HCl solution. Notably, the corrosion resistance of GCI@CS improved with increasing concentration and time. The corrosion inhibition efficiency (ηEIS) of C-steel immersed in 1.0 mol/L HCl (with 500 mg/L GCI@CS) for 24 h reached 93.48 %. This study provides important insights for the industrial deployment of green corrosion inhibitors with controlled release properties.