Investigation of efficient corrosion inhibitor during acid cleaning of reverse osmosis (RO) desalination plant

Abstract

Reverse osmosis (RO) technology plays a vital role in seawater desalination production, while salt scaling phenomenon is an inevitable problem during operation. Accordingly, glucuronide-substituted catechin (CG) was synthesized and developed here as an eco-friendly inhibitor for the first time, whose corrosion inhibition performances for desalination equipment alloys (i.e., carbon steel, brass, Ni-resist, and 316 L stainless steel) in 2% HCl solution were evaluated by experiments and theoretical calculations. At a concentration of 200 mg/L, CG achieved 97.81% corrosion inhibition for carbon steel, 85.91% for Ni-resist, 92.11% for brass, and 77.95% for 316 L stainless steel in weight loss experiments. The 90-hours static stability test was carried out by weight loss method, and the inhibition performance of CG was compared with that of a commercial corrosion inhibitor used in seawater desalination plant. The structural of the protective film on the metal surface was analyzed by EDX and XPS. Quantum chemical calculations based on density functional theory (DFT) and MD simulations were performed to optimize the CG molecular structure and investigate the inhibitive properties on the theoretical level, which agree well with the experimental results.