Biocorrosion Reduction of Pipeline Steel in Desulfovibrio ferrophilus Culture in the Presence of Carboxymethyl Chitosan Grafted Poly(2-methyl-1-vinylimidazole)/Cerium Molybdate Nanocomposite
Bibliographic record
Abstract
In oilfield water systems, the presence of sulfate reducing bacteria (SRB) has caused significant corrosion problems in recent times. On pipeline steel, SRB utilize extracellular electrons from iron oxidation for intracellular reduction of sulfate within the cytoplasm to produce energy, leading to microbiologically influenced corrosion (MIC). In this work, the effects of Desulfovibrio ferrophilus (strain IS5) SRB cellular growth on steel (X70 pipeline steel) corrosion within an anaerobic culture and oilfield-produced water are investigated. SRB are cultured in media of varying concentrations of organic carbon source, using lactate and citrate extracts. To combat MIC, we have also inoculated the SRB culture with different concentrations of a newly synthesized carboxymethyl chitosan grafted poly(2-methyl-1-vinylimidazole)/cerium molybdate nanocomposite. Without this nanocomposite, bacterial growth increased within the culture duration, leading to MIC. MIC episodes are observed as severe anodic steel dissolution. SRB cell counts reduced with the level of carbon source reduction after incubation, but significant cellular survival was observed at extreme carbon starvation. The rate of MIC reduced more than 90 times in the presence of this hybrid nanocomposite under anaerobic conditions, and this has been attributed to the inhibition of SRB cellular growth. D. ferrophilus biofilm growth on steel substrate was analyzed using confocal microscopy with appropriate fluorescent probes. From X-ray photoelectron spectroscopy evidence, the adhering biofilm/corrosion product aggregates on the metallic substrates were mostly ferrous oxides/sulphides. Extensive biocorrosion studies were conducted using electrochemical techniques. Linear polarization resistance and electrochemical impedance spectrometry data confirmed the trend in surface pitting patterns. Our experimental results demonstrate the efficacy of this new chitosan/poly(2-methyl-1-vinylimidazole)/cerium molybdate nanocomposite as a biocide. Without this nanocomposite, the energy needed for cellular survival was harnessed by a combination of extracellular iron oxidation and sulfate reduction even with insufficient carbon source within the media.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".