Corrosion inhibition of Pichia sp. biofilm against mild steel corrosion in 1 M H2SO4

Pichia sp. was isolated from rotten gooseberry (Phyllanthus emblica) and monitored for corrosion inhibition properties by means of biofilm-forming ability. The corrosion inhibition potential of Pichia sp. was evaluated against mild steel corrosion in 1 M H2SO4 via standard weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PP) techniques. Further, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray (EDX), X-ray photoelectron (XPS) spectroscopy, and atomic force microscopic (AFM) techniques were employed for confirming the biofilm accumulation on the mild steel (MS) surface. The weight loss investigation was carried out at varying temperatures (283 K-303 K), which showed the increasing trend of inhibition efficiency (IE%), and decreasing trend of corrosion rate, along with increasing Pichia sp. isolate's concentrations. Pichia sp. isolate has shown maximum corrosion inhibition efficiency (>90%) at 283 K with an optimum concentration of 9 x 106 (CFU/mL). However, temperature studies insisted on the physical adsorption of corrosion inhibitor molecules over the metal surface. EIS data revealed enhanced values of charge transfer resistance (Rct), when increasing Pichia sp. isolate concentrations. Potentiodynamic polarization (Tafel curve) investigation revealed that Pichia sp. isolate exhibited mixed-type corrosion inhibition, while predominantly controlling the anodic reaction. The surface analysis data revealed the adherence and anticorrosive nature of Pichia sp. isolate on the MS surface, and a possible corrosion inhibition mechanism has also been discussed. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Pichia sp. isolated from rotten gooseberry was studied for its corrosion inhibition properties using biofilm formation. The results showed that Pichia sp. has good inhibitory effects on mild steel corrosion in 1 M H2SO4, forming a stable biofilm and reducing corrosion reaction through physical adsorption.