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Corrosion of X80 pipeline steel under sulfate-reducing bacterium (SRB) biofilms, which formed in a culture medium at different times, in a simulated CO 2 -saturated oilfield produced water was investigated. Both planktonic and sessile SRB cells survived after 21 days of immersion in the water under carbon source starvation. The biofilms pre-cultured with a longer time increased the corrosion rate of the steel. At 37 °C, it took about 4 days for SRB to grow and then participate in the steel corrosion. The SRB also facilitated localized corrosion. The SRB biofilm, once deactivated, would no longer affect the steel corrosion. [ABSTRACT FROM AUTHOR]

Corrosion inhibition by benzalkonium chloride (BKC) against anaerobic CO 2 corrosion and microbiologically influenced corrosion was studied using surface analysis, weight loss and electrochemical measurements. Results showed that the minimal bactericidal concentration of BKC against Desulfotomaculum nigrificans ( D. nigrificans ) was 40 mg L −1 . While at this concentration the planktonic D. nigrificans cell count could recover after 21-day incubation, it resulted in 4 log reduction in sessile D. nigrificans cell count. When 80 mg L −1 BKC was used, both planktonic and sessile D. nigrificans became undetectable. It was found that at these concentrations, BKC reduced both uniform corrosion and pitting corrosion. [ABSTRACT FROM AUTHOR]

Inhibition effect of an imidazoline derivative, dodecanoic acid and dodecylamine against CO 2 corrosion and microbiologically influence corrosion in a CO 2 -containing oilfield produced water was studied using surface analysis, weight loss and electrochemical measurements. Results indicated that dodecanoic acid could inhibit the adhesion of iron-oxidizing bacteria (IOB) significantly on carbon steel coupons, but had no effect on the planktonic IOB growth. Its inhibition efficiency reached 88.2% after 43 days of incubation. An imidazoline derivative was found to inhibit the adhesion of IOB on the steel surface, and contributed to lower inhibition effect. [ABSTRACT FROM AUTHOR]

In this paper, the effect of a magneticfield (MF) on biomineralization and corrosion behavior of Q235 carbon steel were studied using surface analysis, weight loss and electrochemical measurements. Experimental results showed that MF inhibited the growth of iron-oxidizing bacteria (IOB) and the corrosion of Q235 carbon steel. MF reduced the largest pit depth by half, while it reduced pit population density from 50 pits cm −2 to 10 pits cm −2 . MF also altered the morphology of biomineralization film, leading to the formation of a more compact biomineralization film which contributed to the lower corrosion rate. [ABSTRACT FROM AUTHOR]

The corrosion behavior of carbon steel was investigated in the presence of SRB and IOB separately in their respective culture media and in the mixed culture of SRB and IOB in artificially produced water with 4.2 mg/L dissolved oxygen. The results showed that IOB inhibited the growth of planktonic SRB, but promoted the growth of sessile SRB when SRB was cultured together with IOB. The mixture of SRB and IOB had a synergistic effect enhancing the pitting corrosion of the coupons. The limited amount of dissolved oxygen played a key role in the formation of corrosion products. [ABSTRACT FROM AUTHOR]

• More Fe2+ leads to better planktonic and sessile Desulfovibrio vulgaris growth. • More Fe2+ increases dissolved H 2 S concentration despite increased FeS precipitation. • More Fe2+ in the culture medium increases carbon steel weight loss and pit depth. • With more Fe2+, increased corrosion is primarily attributed to more sessile cells. • Electrochemical measurements corroborate weight loss and pit depth data. Ferrous ion (Fe2+) in a sulfate reducing bacteria (SRB) culture medium is known to enhance microbiologically influenced corrosion (MIC) of carbon steel, but the underlining mechanism is controversial. This work showed that it was due to better sessile cell growth that was likely attributed to Fe2+ detoxification of H 2 S. Two hundred ppm (w/w) initial Fe2+ in the ATCC 1249 medium achieved a 4.7 times higher Desulfovibrio vulgaris sessile cell count and 5.0 times higher C1018 carbon steel weight loss, compared to 20 ppm. Linear polarization resistance, electrochemical impedance spectroscopy and potentiodynamic polarization measurements corroborated weight loss and pitting data trends. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Molecular simulation confirms that sodium pyrithione (SPT) inhibits iron corrosion. • SPT is found to inhibit planktonic and sessile sulfate reducing bacteria (SRB). • SRB corrosion rate in simulated oilfield produced water is reduced by SPT. • SRB corrosion weight loss data are corroborated by electrochemical measurements. Abstract Anti–bacterial and anti–corrosion properties of sodium pyrithione (SPT) were studied using experimental methods and quantum chemical calculations. SPT at 80 mg/L reduced planktonic and sessile sulfate reducing bacteria (SRB) on X80 carbon steel to undetectable levels. The corrosion inhibition efficiency of SPT against microbiologically influenced corrosion exceeded 80% based on weight loss, which was corroborated by electrochemical data. Molecular modeling showed that SPT molecule provided electrons to the unoccupied orbitals of the Fe surface with a large binding energy of SPT on the Fe (1 1 0) plane, which favored SPT adsorption on the carbon steel. [ABSTRACT FROM AUTHOR]

Highlights • Archaeoglobus fulgidus is a very corrosive sulfate reducing archaeon at 80 °C. • Pre-grown A. fulgidus biofilm is more corrosive under carbon source starvation. • Its corrosion type is extracellular electron transfer MIC (EET-MIC). • This archaeon is capable of using elemental iron as an electron donor. • Linear polarization resistance data support MIC weight loss and pit depth data. Abstract Mature sulfate reducing archaeon (Archaeoglobus fulgidus) biofilm at 80 °C was found more corrosive against C1018 carbon steel under organic carbon starvation. After 3-day pre-growth in enriched artificial seawater medium (EASW), C1018 coupons with biofilms were placed in fresh EASW with reduced carbon source levels for an additional 7 days of incubation. Coupon weight losses were 0.9 mg/cm2, 2.0 mg/cm2 and 1.4 mg/cm2 for this subsequent 7-day starvation period, corresponding to 0%, 90% and 100% carbon source reductions, respectively. Electrochemical tests corroborated the weight loss data, providing evidence for the utilization of elemental iron as electron donor through extracellular electron transfer. [ABSTRACT FROM AUTHOR]

Highlights • Cu MIC by sulfate reducing bacteria (SRB) is shown to be metabolite MIC (M-MIC). • Carbon starvation reduces H 2 S secretion and thus decreases M-MIC of Cu. • In comparison, carbon starvation causes more aggressive MIC against carbon steel. • Cu MIC by SRB causes considerable uniform corrosion with occasional pits. • Cu MIC by SRB and carbon steel MIC by SRB belong to two different MIC types. Abstract Cu corrosion by Desulfovibrio vulgaris , an example of sulfate reducing bacteria (SRB), was investigated. D. vulgaris was first pre-grown in full-strength ATCC 1249 medium with coupons for three days. Then, the medium was switched to fresh media with decreased levels of carbon source. Unlike microbiologically influenced corrosion (MIC) of carbon steel by D. vulgaris , carbon starvation reduced Cu corrosion during the additional seven days of incubation. Experimental data and a thermodynamic analysis indicated that Cu MIC by SRB was caused by secreted sulfide rather than by electron harvesting for energy production, unlikely in the carbon steel MIC by SRB. [ABSTRACT FROM AUTHOR]

Highlights • Electrochemical noise with Hilbert spectral analysis is used to investigate the corrosion mechanism by marine P. aeruginosa biofilm. • Metastable pitting occurred in the region uncovered by P. aeruginosa. • P. aeruginosa likely dissolved the passive film and produced soluble CrO 3 , leading to stable pitting. Abstract The corrosion mechanism of a 2205 duplex stainless steel (DSS) in Pseudomonas aeruginosa inoculated medium was investigated using the information of electrochemical current noise (ECN) transients derived from Hilbert spectra and surface analysis. The pit depths from confocal laser scanning microscopy (CLSM) were analyzed stochastically. Results showed that metastable pitting and stable pitting occurred simultaneously, and they were controlled by different mechanisms in the presence of P. aeruginosa. Metastable pitting occurred in the region uncovered by P. aeruginosa unlike stable pitting. P. aeruginosa likely dissolved the passive film and produced soluble CrO 3, leading to stable pitting. [ABSTRACT FROM AUTHOR]

Enhanced oil recovery typically relies on injection of seawater mixed with chemicals to increase reservoir pressure. A polymer such as partially hydrolyzed polyacrylamide (HPAM) is often added to increase viscosity. In this work, an oilfield biofilm consortium was found to utilize a commercial HPAM-based polymer. The polymer at 1000 ppm (w/w) promoted the growth of planktonic cells and sulfate reducing bacteria sessile cells in an artificial seawater medium during a 30-day incubation period in anaerobic vials. The polymer utilization led to 34.5% viscosity loss and more severe microbiologically influenced corrosion weight loss and pitting against C1018 carbon steel. [ABSTRACT FROM AUTHOR]

The role of biogenic H 2 S in the microbiologically influenced corrosion (MIC) of carbon steel was investigated. Desulfovibrio vulgaris (ATCC 7757), a sulfate reducing bacterium, was tested against C1018 carbon steel in anaerobic vials with three different sizes, each filled with 40 mL of ATCC 1249 culture medium, providing headspace volumes of 10 mL, 85 mL and 160 mL, respectively for H 2 S to escape. Results showed that a larger headspace led to a lower H 2 S concentration in the culture medium, and this increased the sessile cell count and made the iron sulfide film thinner, resulting in increased MIC. [ABSTRACT FROM AUTHOR]

This work showed that a wild-type Pseudomonas aeruginosa (PAO1) grown as a nitrate reducing bacterium biofilm on C1018 carbon steel was more corrosive under organic carbon source starvation. P. aeruginosa biofilms were pre-grown for 2 days to achieve maturity before the culture media were changed to fresh culture media with 100% (as in the standard medium), 10%, and 0% organic carbons for subsequent 7-day incubation. Biofilms with 100%, 10%, and 0% organic carbons caused maximum pit depths of 5.4 μm, 10.6 μm, and 17.0 μm, respectively. Weight loss, linear polarization resistance and electrochemical impedance spectroscopy data corroborated the pitting data. [ABSTRACT FROM AUTHOR]

Abstract: Nitrate injection is used to suppress reservoir souring in oil and gas fields caused by Sulfate Reducing Bacteria (SRB) through promotion of nitrate respiration by Nitrate Reducing Bacteria (NRB). However, it is not well publicized that nitrate reduction by NRB can cause Microbiologically Influenced Corrosion (MIC) because nitrate reduction coupled with iron oxidation is thermodynamically favorable. NRB benefits bioenergetically from this redox reaction under biocatalysis. This work showed that the Bacillus licheniformis biofilm, when grown as an NRB biofilm, caused a 14.5μm maximum pit depth and 0.89mg/cm2 normalized weight loss against C1018 carbon steel in one-week lab tests. [Copyright &y& Elsevier]