Green mitigation of microbial corrosion by copper nanoparticles doped carbon quantum dots nanohybrid

Recently, nanomaterials have been introduced as a new generation of inhibitors to control the microbiologically influenced corrosion (MIC). In this study, copper nanoparticles doped carbon quantum dots (Cu/CQDs) nanohybrid was used as an inhibitor to reduce the MIC. FESEM, EDS, FTIR, and XRD were used to characterize the nanohybrid. The dose-response test was performed to evaluate the inhibitory effect of Cu/CQDs against SRB. Design-Expert software was used to design the matrix of experiment and analyze the result. Cu/CQDs showed significant inhibitory effect against SRB compared to the copper nanoparticles (CuNPs) and carbon quantum dots (CQDs), at 50 ppm. Moreover, corrosion behavior of X60 steel was evaluated via electrochemical impedance spectroscopy (EIS) and Tafel polarization techniques in the presence of SRB and Cu/CQDs. The fitted result of EIS showed that the charge transfer resistance (R_ct) value increased in the presence of Cu/CQDs owing to the enhancement in the thickness of the electrical double layer, indicating that Cu/CQDs is able to provide significant corrosion protection to X60 steel in the presence of SRB. In addition, FESEM, EDS, and XRD were used to study the formed corrosion products and biofilm on the surface of X60 steel. Corrosion test results indicated that the addition of the Cu/CQDs reduced the surface damage of X60 steel in the presence of SRB. It is attributed to the carbon dots adsorption film formation, which possessed a significant protective ability to inhibit the corrosion of steel in the presence of SRB.