Galvanic Corrosion Due to a Heterogeneous Sulfate Reducing Bacteria Biofilm

Hongwei Liu,Haixian Liu,Yuxuan Zhang

doi:10.3390/coatings10111116

Abstract

In this work, the galvanic corrosion behavior of sulfate reducing Desulfotomaculum nigrificans biofilm-covered and uncovered carbon steel was investigated using various electrochemical measurements. The results showed that the bare specimen in the abiotic solution functions as the anode; whereas the biofilm-covered specimen in the SRB-containing solution functions as the cathode after two electrodes being coupled. The anodic reaction of specimen in the biotic solution containing SRB was inhibited; whereas the cathodic reaction was considerably promoted after coupling. Hence, localized corrosion of specimen in the abiotic solution was observed due to the galvanic corrosion effect. SRB could still accelerate steel corrosion even after coupling, but the results indicate that the contribution of SRB to steel corrosion decreased. The localized corrosion of steel in the SRB-containing environments not only involved the SRB biofilm, but also a galvanic corrosion effect. The flow of electrons from the anodic dissolution of Fe in the abiotic solution to the SRB cells of cathodic area decreased the acceptance capacity of electrons by SRB from steel beneath biofilm. As a result, the steel corrosion beneath SRB biofilm decreased after coupling.

Highlights

Influenced corrosion (MIC) has been considered as one of the key reasons causing the failure of pipelines [1,2]
40 were disksmore were placed in the those in the abiotic solution. This means that the specimen in the abiotic solution is as the anode; than those in the abiotic solution. This means that the specimen in the abiotic solution is as the anode; abiotic test solution
The above results (Figures 2–6) have shown that there was a galvanic effect between the specimens in the abiotic and Sulfate reducing bacteria (SRB)-containing solution, where the specimen in the abiotic solution acts as the anode and the specimen in the SRB-containing solution acts as the cathode

Summary

Introduction

Influenced corrosion (MIC) has been considered as one of the key reasons causing the failure of pipelines [1,2]. Sulfate reducing bacteria (SRB) have been commonly found in various environments, including oil produced water, sea water, soil, and sewage [3,4]. SRB MIC can significantly accelerate the localized corrosion against pipeline steel in the oil and gas industry [5]. The localized corrosion is the biggest threat to the safe running of pipelines. Some researchers have proposed some SRB corrosion mechanisms, including cathodic depolarization, oxygen-concentration cell, biocatalysis, etc. The localized corrosion mechanism induced by SRB is still ambiguous, because SRB corrosion environment is very complex but changes in natural conditions

Results

Discussion

Conclusion