Graphene oxide/silver nanostructure as a green anti-biofouling composite toward controlling the microbial corrosion

Abstract

Microbiologically influenced corrosion is a serious problem in the oil and gas industry, which leads to both economical losses and environmental pollutions. To control biocorrosion and prevent the problems, using biocides is the main solution. Recently, nanomaterials have been introduced as a new generation of biocides to control the biocorrosion. In this study, graphene oxide/silver nanostructure was synthetized, and its biocidal effect was evaluated by a dose–response test. The response surface methodology in the Design-Expert software was used to analyze the result, and to determine the optimum concentration of nanostructure to inhibit sulfate reducing bacteria, which was 80 mg/L. The corrosion morphology and the composition of the formed corrosion products were studied using surface analysis methods. The result illustrated the uniform corrosion and significantly reduced amount of iron sulfide in the presence of nanostructure, due to the inhibition of sulfate reducing bacteria. In comparison, the pitting corrosion was observed on the surface of the exposed coupon to the bacteria, and the high presence of iron sulfide in the corrosion products. The corrosion behavior of steel in the presence of the bacteria and the nanostructure was investigated via electrochemical impedance spectroscopy and Tafel polarization techniques. Corrosion test result indicated that the addition of the nanostructure increased the charge transfer resistance, resulting in the reduction in corrosion rate. This is attributed to preventing the production of biofilm by the nanostructure and the formation of a protective film in the presence of graphene oxide nanosheets.