8‐Hydroxyquinoline‐functionalized chitosan Schiff base as an efficient and environmentally friendly corrosion inhibitor for N80 steel in acidic environments

Abstract

Chitosan is an environmentally friendly biomolecule with great potential for application in metal corrosion protection. First, Chitosan benzaldehyde schiff base (CTSB) and 8‐hydroxyquinoline functionalized chitosan benzaldehyde schiff base (HQ‐CTSB) were synthesized from chitosan, benzaldehyde, and 8‐hydroxyquinoline as high‐efficiency and environment‐friendly corrosion inhibitors. The structures of the synthesized products were characterized by infrared spectroscopy. The corrosion of N80 steel was tested using electrochemical measurements and analysis by varied concentrations of CTSB and HQ‐CTSB in a hydrochloric acid solution. The PDP results confirmed that both CTSB and HQ‐CTSB corrosion inhibitors were mixed corrosion inhibitors. Furthermore, the EIS findings revealed that the corrosion inhibition efficiency of the two inhibitors was 87.11% and 98.52% at 800 mg/L, respectively. According to SEM and XPS analyses, the CTSB and HQ‐CTSB molecules bonded to the surface of N80 steel and formed a surface protective layer. Density functional theory (DFT) calculations showed that CTSB and HQ‐CTSB have multiple active sites that may become adsorbent on the metal surface. And molecular dynamics (MD) simulations showed that corrosion inhibitors CTSB and HQ‐CTSB lie flat on the surface of Fe(110). The theoretical calculation agreed well with the experimental results.

Preparation and corrosion inhibition mechanism of a chitosan ionic liquid Schiff base for the protection of N80 in HCl solution

“…The formed imine (–HCN–) linkage and the introduced functional groups or molecular segments will together improve the adsorption behavior of CS-IL on metal surface. 24–26 Chauhan et al synthesized a totally new Schiff base of CS-IL, namely, Piperonal-Chitosan (Pip-Cht) using the microwave irradiation method and applied the obtained Pip-Cht as a corrosion inhibitor to the oil-well acidic environment. At a moderate dose of 600 mg L −1 , the Pip-Cht inhibitor exhibited a high corrosion inhibition efficiency of 85.16%.…”