Functional development of extracts from the invasive plant water hyacinth for steel corrosion protection

Inhibitors with good effects and eco-friendly advantages are significant in cold-rolled steel (CRS)-consuming industries. Water hyacinth is an invasive plant that threatens biodiversity. Herein, the water hyacinth extract (WHE) as an inhibitor exhibited a high corrosion inhibition efficiency of 91.3% for CRS in a trichloroacetic acid (TCA) solution at a concentration of 300 mg·L−1. Potentiodynamic polarization moved negatively and the time-constant capacitance loop in the Nyquist plot revealed that WHE acts as a mixed inhibitor, reducing both anodic and cathodic corrosion processes. Characterization tests confirmed that WHE forms a hydrophobic adsorption layer on CRS via physical and chemical adsorption. Theoretical calculations proved that the effective component—palatinose in WHE, shows a satisfactory protection effect on the CRS because of its outstanding adsorption effect and interaction energy resulting from its chemical composition and structure. This study may offer valuable insights into the high-value utilization of invasive plants in the anti-corrosion field.