Microbiological Induced Corrosion and Inhibition

Abstract

Microbial corrosion refers, by definition, to the degradation of materials due to the activity of a wide variety of microorganisms, usually embedded in a gel matrix—the biofilm—attached to the surface. The feature of MIC (microbial induced corrosion) is connected to three factors: microorganisms involved (bacteria, algae, moulds or fungi, individually or in combination), material, and environment (solution and conditions). In particular, degradation of metallic structures derives from the activity of a wide variety of microorganisms, either directly participating in electrochemical reactions on the metal surface or producing aggressive metabolites capable of making the environment corrosive. A wide range of microorganisms may be involved in corrosion processes, such as chemical attack of metals, concrete and other materials, by means of the by‐products of microbe metabolism, for example, sulfuric and carbonic acids, hydrogen sulfide or ammonia; attack of metal by a process in which the corrosion reaction is sustained by the combined action of microbes and metal or by a combination of bacteria; depassivation of metal surfaces and induction of corrosion cells; depolarization of cathodic reaction; microbial attack of organic materials (e.g., paint coatings, plastic linings), degradation of inhibitors, conversion of natural inorganic compound (e.g., sulfur). Remedial actions are similar to those taken to avoid corrosion, but must be applied much more rigorously, as once it starts, it is extremely difficult to stop MIC. Preventive actions include optimum design of the plant at the early stage and proper material selection based on expected operative and environmental conditions.

Performance of environmentally friendly, liquid-infused coatings against biofouling: evaluation of macrofouling and microbially induced corrosion in freshwater environments

“…Increased hydrodynamic resistance, caused by drag forces from the roughened ship hulls, raises fuel consumption and leads to higher emissions and costs for fuel (by up to 40%) 5 as well as time-and resource-consuming cleaning procedures. 4,6,7 Some microorganisms, e.g., sulfatereducing (SRB), sulfur-oxidizing (SOB), iron-oxidizing (IOB), or iron-reducing (IRB) bacteria, can cause MIC through their bio-lms and metabolic products, 8,9 and thus compromise the stability of aquatic infrastructure. Various MIC mechanisms require completely different physical and chemical conditions, but what they have in common is that they either directly or indirectly promote the key reaction in the corrosion of ironcontaining metals: Fe 0 / Fe 2+ + 2e − .…”

“…4,6,7 Some microorganisms, e.g. , sulfate-reducing (SRB), sulfur-oxidizing (SOB), iron-oxidizing (IOB), or iron-reducing (IRB) bacteria, can cause MIC through their biofilms and metabolic products, 8,9 and thus compromise the stability of aquatic infrastructure. Various MIC mechanisms require completely different physical and chemical conditions, but what they have in common is that they either directly or indirectly promote the key reaction in the corrosion of iron-containing metals: Fe 0 → Fe 2+ + 2e − .…”

Biofilm Development on Carbon Steel by Iron Reducing Bacterium Shewanella putrefaciens and Their Role in Corrosion

“…In the limited studies on the topic, the corrosion acceleration due to IRB is attributed to the bacteria's ability to produce soluble ferrous irons through reductive dissolution of the protective corrosion film of insoluble ferric iron oxides on the steel surface, thereby exposing the alloy surface to aggressive ions in the environment [10,12,13]. However, a few laboratory studies have reported the protective effect of IRB [14,15]. Lee and Newman reported that even if biofilm coverage of the metal is incomplete, cumulative O 2 respiration from both planktonic and sessile cells rapidly depletes O 2 on the metal surface, thus inhibiting the galvanic process and corrosion [16].…”