Comprehensive evaluation of corrosion inhibition performance and ecotoxicological effect of cinchona IIa as a green corrosion inhibitor for pickling of Q235 steel.

Here, to prevent the corrosion of Q235 steel in the pickling and discover novel green corrosion inhibitors, the corrosion inhibition performance and eco-toxicity of cinchonain IIa were evaluated. Electrochemical experiments confirms that 200 mg/L cinchonain IIa reveals good corrosion inhibition performance with 94.08% on Q235 steel in HCl for 48 h. Scanning electron microscope (SEM) and atomic force microscope (AFM) observations suggest that cinchonain IIa can be firmly attached to the metal surface by forming a barrier film. The X-ray photoelectron spectroscopy (XPS) results further verify the bonding interaction between the functional groups and the steel matrix, and indicate the existence of protective film on the steel. Meanwhile, the inhibition mechanism at the molecular/atomic level is revealed through molecular dynamics simulation. Additionally, acute toxicity test shows that cinchonain IIa is a low toxic corrosion inhibitor. Moreover, the antioxidant enzyme activity experiments confirm that cinchonain IIa discloses no obvious damage to the antioxidant system of zebrafish. Overall, cinchonain IIa exhibits low potential risks to the healthy development of aquatic organisms and ecosystems. As a proven green and low toxic corrosion inhibitor, cinchonain IIa has a sustainable application in the anti-corrosion industry.