Facile and green synthesis of Ag/Cu bimetallic nanoparticles using waste banana peel extract for effective corrosion inhibition of mixed sulfate-reducing bacteria.

Microbiologically induced corrosion (MIC) is widespread in the oilfield industry, and new environmentally friendly materials are urgently needed to inhibit MIC with the increasing environmental requirements and microbial resistance problems. The synthesis method and cost of the materials are important factors that must be considered in the production and application. In this study, Ag/Cu bimetallic nanoparticles (BNPs) were synthesized by eco-friendly and sustainable method using waste banana peel extract (BPE) as a green reducing. The antibacterial and corrosion inhibition properties of Ag/Cu BNPs were investigated by using the enriched mixed strains containing sulfate-reducing bacteria (SRB) as model bacteria. The results of electron microscopy showed that the prepared BNPs exhibited spherical structure with about 19.0 nm in size. The synthesized nanoparticles significantly inhibited the growth of mixed strains by antimicrobial experiments with minimum inhibitory concentration (MIC) value of 9.38 μg/mL. The addition of Ag/Cu BNPs (9.38 μg/mL) inhibited the corrosion of X65 carbon steel induced by the mixed strains with 77.9% compared to the untreated condition. Correspondingly, the number of sessile SRB cells in the solution containing Ag/Cu BNPs (9.38 μg/mL) after 28 days of immersion decreased by 5-log compared with the treatment group without nanomaterials (1.1 × 108 cells/cm2). Furthermore, the observation of the surface morphology and strains cellular microstructure of carbon steel treated with nanoparticle materials illustrated that the corrosion inhibition mechanism mainly includes destroying cell structure, affecting metabolic activities and inhibiting biofilm formation. The environmentally friendly nanoparticle materials prepared in this study have great potential in the safe and clean production of oil fields.