Zn Wetted CeO₂ Based Composite Galvanization: An Effective Route To Combat Biofouling

Abstract

The present paper reports for the first time the development and application of novel Zn wetted CeO 2 (Zn/ CeO 2 ) composite galvanic zinc coating to combat microbial induced corrosion (MIC). Zinc metal−metal interaction causes the effective incorporation of composite into the galvanic coating and accordingly increases the active sites for antibiofouling activity. The developed coatings are explored for their anticorrosion/antibiofouling characteristics toward MIC induced by cultured seawater consortia. Enhanced antibiofouling activity of the composite galvanic coating is achieved due to the tuned content of 28 wt % Zn and 34 wt % of Ce. High charge transfer resistance as high as 4.0 × 10 14 Ω cm 2 and low double layer capacitance as low as 3.99 × 10 −8 F are achieved by tuning the structure and composition of the coating. The synergistic effect of Zn and Ce ensures the stability and corrosion resistance of the coatings in a corrosive bacterial environment. Evident decreases in the bacterial attachment and biofilm formation are illustrated using antibiofouling assay. The antibiofouling activity is attributed to the effective reduction of Ce 4+ to Ce 3+ and the shuttling characteristics of oxidation state of CeO 2 . This impairs the cellular respiration and results in bacterial death. Thus, it can be used as an effective coating to protect the steel based equipment in corrosive marine environments to combat marine microorganisms and their interactions. The present study also paves the scope for exploration of similar effective protective systems.

Development of Antibacterial V/TiO2-Based Galvanic Coatings for Combating Biocorrosion

“…The pure zinc coating exhibits a low E corr value after 21 days of immersion in different bacterial cultures. It is confirmed that that the pure zinc coating accelerates the corrosion reaction by allowing the passage of corrosive ions into the coating/metal interface and enhances the anodic dissolution reaction. ,, …”

“…The long-term stability and combating biocorrosion capability of the developed coatings after 21 days of immersion in different bacterial cultures were evaluated by recording the OCP value with respect to SCE and are shown in Figure S9. All the coatings in different bacterial cultures exhibit negative potential during the initial days, which is attributed to the formation of the sacrificial layer on the coating which protects the metal substrate . As the exposure time increases, the OCP value of pure zinc coating shifts to the more anodic region in different bacterial cultures.…”

“…Steels are extensively used in almost all industries due to their good mechanical properties, availability, recyclability, flexibility, economic viability, and constructability. − Mild steels are frequently used in the fabrication of reaction vessels, storage tanks, and petroleum refineries . However, the performance of mild steel is affected by corrosion.…”

“…In this context, the present work aims to develop environment-friendly coatings with long durability, enhanced electrochemical properties, and long-term stability against biocorrosion. Zinc coating is widely applied as a metallic coating for corrosion prevention on mild steel substrates. , Due to high strength, formability, recyclability, long-term stability, and high anti-corrosion performance, hot-dip galvanized zinc coating is extensively used in all industrial and marine fields. , The superior anticorrosion performance and long-term stability of the zinc coating are due to the three-fold protective nature. , When the zinc coating has some defects and pores formed on its surface, then the coating acts as a sacrificial anode. , Modification of the zinc bath by alloying elements significantly affects the kinetics, surface morphology, and coating growth. , The presence of metal oxides such as ZrO 2 , Al 2 O 3 , TiO 2 , WO 3 , and CeO 2 in the zinc bath causes the formation of an oxide barrier coating and thereby enhances the anticorrosion performance of the interior layer of the coating. − ,− The main limitation of the zinc coating in the aquatic and marine environments is the bacterial adhesion and biofilm proliferation on the surface which enhance the anodic dissolution of the coating . Therefore, a coating with high antibacterial activity should inhibit bacterial adhesion and biofilm proliferation on the surface …”

“…The incorporation of some metal oxides such as TiO 2 and CeO 2 into the zinc coating enhances the anti-biofouling properties of the coating. ,, Among various metal oxides, TiO 2 has drawn much more attention in current emerging research areas such as solar energy conversion and environmental application due to its high chemical stability, nontoxicity, wettability, and notable photocatalytic ability to remove environmental pollutants. , The antibacterial activity of TiO 2 under visible light irradiation is of significant interest for water treatment . However, the photocatalytic and antibacterial activities of TiO 2 nanoparticles are still relatively small because of their large band gap (3.2 eV). ,− Doping with metals or nonmetals into the TiO 2 lattice is an effective method for improving the photocatalytic and antibacterial ability of TiO 2 under visible light irradiation by shifting the absorption peak from UV to the visible region. , However, the transition-metal-doped TiO 2 has high photocatalytic and antibacterial activity in the visible light region.…”