Biological Functionalization of a Sol–Gel Coating for the Mitigation of Microbial‐induced Corrosion

Abstract

The addition of biocides to water systems has been the most direct attempt to limit or mitigate the formation of surface biofilms that lead to the development of microbial‐induced corrosion (MIC), a process that costs industry millions of pounds annually. The efficacy of this approach is dependent upon a) the biocide being delivered to all water–metal substrate interaction sites and b) the biocide remaining active, therein preventing biofilm development/growth. Anti‐fouling biocide additions to water supplies, or anti‐fungal additives in paints, have an adverse impact upon the environment, for example, tri‐butyl tin is toxic to aquatic life. An alternative non‐toxic approach currently being pursued by the authors involves localizing a biologically active reagent close to the metal substrate. Localization in this case is achieved by synthesizing a hybrid functional sol–gel coating and encapsulating a suitable non‐pathogenic biological component within the sol–gel matrix. Distribution within the sol–gel coating of vegetative bacteria or spores has been confirmed using various microscopy techniques. Electrochemical data in the form of polarization resistance, impedance spectroscopy, and electrochemical noise all show that the presence of either P. fragi or P. polymyxa within a sol–gel coating leads to a corrosion resistance improvement at least 10 times that of an equivalent abiotic coating. Confirmation of this improvement is derived from six months of field trial testing conducted in a tidal estuarine environment. Comparative tests that use a control sol–gel coating immersed within nutrient poor artificial seawater that contained freely suspended P. polymyxa reveal no marked improvement over a control sample in the absence of the endospores.

Grafting of antibacterial polymers on stainless steel via surface‐initiated atom transfer radical polymerization for inhibiting biocorrosion by Desulfovibrio desulfuricans

“…Different strategies have been developed to address the growing need for combating biocorrosion (Akid et al, 2008;Al-Darbi et al, 2002;Cetin et al, 2007;Guezennec, 1994;Muthukumar et al, 2007;Sreekumari et al, 2005;Videla, 2002;Yebra et al, 2004). Biocidal treatment is a conventional approach for mitigating the problem of biofouling and biocorrosion in closed systems, such as potable water distribution systems (Mohanan et al, 2005;Videla, 2002).…”

Anticorrosion/antifouling properties of bacterial spore-loaded sol–gel type coating for mild steel in saline marine condition: a case of thermophilic strain of Bacillus licheniformis

“…The concept of MIC inhibition using biolms of Paenibacillus polymyxa and Pseudomonas fragi within sol-gel matrix has been evaluated to give a novel protective coating for aluminium alloy. 15 The corrosion inhibition by other sporeforming Gram-positive bacteria have also been widely reported in the literature for many metal substrates in both freshwater and seawater. These microbes alter the rate of metal dissolution as long as they remain viable in the media by reducing the concentration of oxygen at the metal surface via aerobic respiration.…”

“…Adequate choice of the precursor chemistry, reaction conditions and biolm of inoculums of protective bacteria could produce functionalized hybrid solgels with good aging, stability, shelf life, MIC and fouling inhibition properties. Recent studies 15,16 have shown that mitigating MIC and biofouling by encapsulating endospores of protective bacteria in the sol-gel coating on metal substrates gives improved corrosion and fouling protection in comparison to sol-gel alone. The concept of MIC inhibition using biolms of Paenibacillus polymyxa and Pseudomonas fragi within sol-gel matrix has been evaluated to give a novel protective coating for aluminium alloy.…”

Prevention and control of microbiologically influenced concrete deterioration in wastewater concrete structures using E.coli biofilm

“…Biofilms can inhibit corrosion thorough: 1) removal of corrosive agents (Zuo, 2007) ( Figure 2.1a), 2) growth inhibition of SRB by antimicrobial compounds secreted within the biofilm (Zuo, 2007) (Figure 2.1b), 3) formation of protective corrosion products (Akid et al, 2008) (Figure 2.1c), 4) uptake of water by the bacteria within the biofilm as a result of metabolic activity (Akid et al, 2008).…”

“…It is likely that some other activities might be involved rather than oxygen depletion alone in the corrosion inhibition by E.coli biofilm (Zuo, 2007). Akid et al (2008)…”