Effect of nano-zerovalent iron incorporated polyvinyl-alginate hybrid hydrogel matrix on inhibition of corrosive bacteria in a cooling tower water environment

Abstract

Microbial-induced corrosion (MIC) is an insidious process caused by microbial growth on metals. Among many metals, aluminium, brass, mild steel, stainless steel and carbon steels are more vulnerable to MIC. The present study investigates one of the effective corrosion protection strategies using hybrid hydrogel coating. In this regard, the anti-corrosive activity of n-zerovalent iron (nano-ZVI) incorporated polyvinyl-alginate (PVA) hybrid hydrogel-coated matrix against MIC on aluminium, Al 1100 metal, was tested. The study was conducted against corrosion-inducing bacteria, Terribacillus aidingensis EN3 (Accession number: KR183874), isolated from cooling tower water system. The antibacterial results of nano-ZVI showed a diameter of zone of inhibition at 10 mg/mL. Hybrid hydrogel matrix was employed against the MIC in cooling tower water-containing systems, I, II and III, IV along with a control. The results of the study were supported with weight loss (WL) analysis and electrochemical impedance spectroscopy (EIS) studies. WL results showed a reduced rate of 0.08 mm/y corrosion in hybrid hydrogel system than the other systems. The EIS studies showed higher charge transfer resistance (R ct ) of 14.53 Ω and solution resistance of 3.8 Ω. These results confirmed the presence of nano-ZVI in hybrid hydrogel acted as an antibacterial agent in the PVA-alginate protective film against corrosion in Al 1100. Thus, the obtained results evidenced the novel idea of hydrogel matrix to act as an anti-corrosive film in the cooling tower system.