Graphene oxide modified with imidazoline quaternary ammonium salt: Water-soluble inhibitor for anticorrosion of the corrosion of carbon steel in oilfield wastewater

Graphene oxide (GO) has become a topic of interest in the field of anti-corrosion coating. However, in the field of oilfield wastewater corrosion prevention, there are few research reports on the application of GO aqueous solutions as corrosion inhibitors. This paper discovered that GO modified by acylating with imidazoline quaternary ammonium salt (IQAS) can be preferentially adsorbed on carbon steel surfaces to form a relatively dense protective layer, significantly improving the corrosion resistance of carbon steel in oilfield wastewater. N80# carbon steel was taken as the corrosion object, and oilfield wastewater as the corrosion medium to simulate the corrosion of metal equipment in oilfield wastewater during crude oil storage and transportation. The electrochemical polarization curve method, impedance spectrum method, weight loss method, corrosion morphology, and product characterization were used to understand the corrosion inhibition behavior and anti-corrosion mechanism of the GO aqueous solution. The results showed that the corrosion rate of steel sheet with 0.06% GO added at 40°C was 2.023 mm/a, which was 36.15% lower than 3.1685 mm/a in the blank control group. When 0.06% GO and 2.0% IQAS were added simultaneously, the corrosion rate was 1.6494 mm/a, which decreased by 47.94% compared with the blank control group. By weight loss method, the corrosion rate in the crude oil wastewater containing 0.06% GO and 2.0% IQAS at 40°C for 72 h was 0.0768 mm/a, which was 47.5% lower than that in the blank group. The anti-corrosion mechanism involves the inhibition being adsorbed onto the surface of the steel sheet, thereby improving the electrochemical corrosion impedance and reducing the corrosion rate. This research result will provide a novel idea for the development of corrosion and corrosion inhibitors of GO.