Glycyrrhiza glabra extract as an eco-friendly inhibitor for microbiologically influenced corrosion of API 5LX carbon steel in oil well produced water environments

Elastic and Self-Healing Copolymer Coatings with Antimicrobial Function

The revolutionary self-healing function for long-term and safe service processes has inspired researchers to implement them in various fields, including in the application of antimicrobial protective coatings. Despite the great advances that have been made in the field of fabricating self-healing and antimicrobial polymers, their poor transparency and the trade-off between the mechanical and self-healing properties limit the utility of the materials as transparent antimicrobial protective coatings for wearable optical and display devices. Considering the compatibility in the blending process, our group proposed a self-healing, self-cross-linkable poly{(n-butyl acrylate)-co-[N-(hydroxymethyl)acrylamide]} copolymer (AP)-based protective coating combined with two types of commercial cationic antimicrobial agents (i.e., dimethyl octadecyl (3-trimethoxysilylpropyl) ammonium chloride (DTSACL) and chlorhexidine gluconate (CHG)), leading to the fabrication of a multifunctional modified compound film of (AP/b%CHG)-grafted-a%DTSACL. The first highlight of this research is that the reactivity of the hydroxyl group in the N-(hydroxymethyl)acrylamide of the copolymer side chains under thermal conditions facilitates the "grafting to" process with the trimethoxysilane groups of DTSACL to form AP-grafted-DTSACL, yielding favorable thermal stability, improvement in hydrophobicity, and enhancement of mechanical strength. Second, we highlight that the addition of CHG can generate covalent and noncovalent interactions in a complex manner between the two biguanide groups of CHG with the AP and DTSACL via a thermal-triggered cross-linking reaction. The noncovalent interactions synergistically serve as diverse dynamic hydrogen bonds, leading to complete healing upon scratches and even showing over 80% self-healing efficiency on full-cut, while covalent bonding can effectively improve elasticity and mechanical strength. The soft nature of CHG also takes part in improving the self-healing of the copolymer. Moreover, it was discovered that the addition of CHG can enhance antimicrobial effectiveness, as demonstrated by the long-term superior antibacterial activity (100%) against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria and the antifouling function on a glass substrate and/or a silica wafer coated by the modified polymer.

Anticorrosive performance of newly synthesized dipyridine based ionic liquids by experimental and theoretical approaches

Two newly synthetic nontoxic dipyridine-based ionic liquids (PILs) with the same chain lengths and different polar groups were investigated: bispyridine-1-ium tetrafluoroborate (BPHP, TFPHP) with terminal polar groups Br and CF3, respectively, on Carbon steel (CS) in 8M H3PO4 as corrosion inhibitors. Their chemical structure was verified by performing 1HNMR and 13CNMR. Their corrosion inhibition was investigated by electrochemical tests, especially as mass transfer with several characterizations: Scanning electron microscope/Energy dispersive X-ray spectroscopy (SEM-EDX), UV-visible, Atomic force microscope, Atomic absorbance spectroscopy, X-ray Photoelectron Spectroscopy and Gloss value. Theoretical calculation using density functional theory by calculating several parameters, molecular electrostatic potential, Fukui Indices, and Local Dual Descriptors were performed to demonstrate the reactivity behavior and the reactive sites of two molecules with a concentration range (1.25-37.5 × 10-5 M) and temperature (293-318 K). The maximum inhibition efficiency (76.19%) and uniform coverage were sufficient for BPHP at an optimum concentration of 37.5 × 10-5 M with the lowest temperature of 293 K. TFPHP recorded 71.43% at the same conditions. Two PILs were adsorbed following the El-Awady adsorption isotherm, including physicochemical adsorption. The computational findings agree with Electrochemical measurements and thus confirm CS's corrosion protection in an aggressive environment.

Analysis of the Antibacterial Activity and the Total Phenolic and Flavonoid Contents of the Moringa oleifera Leaf Extract as an Antimicrobial Agent against Pseudomonas aeruginosa

Pseudomonas aeruginosa is a bacterium that causes metal deterioration by forming biofilms on metal surfaces. This work was carried out to analyze the antibacterial activity and the phenolic and flavonoid contents of the Moringa oleifera leaf extract against Pseudomonas aeruginosa. M. oleifera leaves were extracted in a methanol solution at different concentrations. The M. oleifera leaf extract yields were 12.84%, 18.96%, and 19.64% for the 100%, 75%, and 50% methanol ratios, respectively. Extracts of M. oleifera leaves had a minimum inhibiting concentration (MIC) of approximately 6144 μg/mL against P. aeruginosa for a ratio of 100% methanol. In addition, no antibacterial activity was found for the 75% and 50% methanol ratios. The total phenolic levels were 16.26%, 12.73%, and 12.33% for the 100%, 75%, and 50% methanol solvent ratios, respectively. The total amounts of flavonoids were 23.32%, 3.40%, and 0.64% for the 100%, 75%, and 50% methanol solvents, respectively. The chemical structure of M. oleifera consists of kaemferol-3-O-rutinoside, quercimeritrin, kaempferol-3-O-β-D-glucopyranoside, stearidonic acid, trichosanic acid, pyrophaeophorbide A, and stigmastan-3,6-dione. The concentration of the solvent is essential in the extraction of plant constituents. Different concentrations indicate differences in antibacterial activity, phenolic and flavonoid contents, and chemical structure.

Novel biphenylidene-thiopyrimidine derivatives as corrosion inhibitors for carbon-steel in oilfield produced water

The inhibiting efficiency of three newly synthesized organic compounds:5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (HM-1228), 5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (HM-1227) and 5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-trione (HM-1226) in oilfield produced water on the corrosion of carbon steel has been examined via electrochemical measurements; potentiodynamic polarization (PDP) and electrochemical impedance (EIS) techniques. The adsorption of these compounds on the surface of carbon steel followed Langmuir isotherm. In addition, the surface morphology of uninhibited and inhibited carbon steel was examined by Atomic Force Microscopy (AFM), observing surface improvement when carbon steel samples exposed to the inhibited corrosive solutions. The average surface roughness (Ra) in oilfield produced water solution in the presence of 0.5 mM of HM-1228 inhibitor was 138.28 nm compared to the uninhibited surface 571.62 nm. To explore the corrosion inhibition mechanism, quantum chemical calculations and Monte Carlo simulations were utilized. The HM-1228 inhibitor demonstrated the highest corrosion inhibition efficiency at 94.8% by PDP measurements. The higher corrosion inhibition of compound HM-1228 can be attributed to the presence of di-N-ethyl groups that enhance both electron donating ability and lipophilic properties.

Metagenomics diversity analysis of sulfate-reducing bacteria and their impact on biocorrosion and mitigation approach using an organometallic inhibitor

Sulfate-reducing bacteria (SRB) have impacted the biocorrosion process for various industrial sectors, especially in the oil and gas industry. The higher stability over extreme conditions is the key parameter for their survival in such environments. So far, many materials have been tried to minimize or control the growth of SRB. In the present study, an organo-metallic compound of the zinc sorbate (ZS) was successfully synthesized by the simple co-precipitation method and its improved antibacterial activity against SRB. The SRB consortia are enriched from the sub-surface soil sample and identified by 16s rDNA sequencing by targeting the V3-V4 region. The most dominating genera identified with sulfate-reducing capability are Sulfurospirillum (42 %), Shewanella (19 %) Bacteroides (14 %), and Desulfovibrio (8 %). Further biocorrosion experiments are conducted by weight loss methods. Higher corrosion current density (I_corr) and less charge transfer resistance (R_ct) are observed for the SRB consortia. Concurrently, higher R_ct is kept for the inhibitor-included systems. The slowest release of the sorbate into the medium suppressed the growth of the SRB bacterial cells with 86 ± 3 % corrosion inhibition efficiency and prevented further corrosion reactions by forming a protective layer over the surface of the carbon steel API 5LX. The surface analysis strongly confirmed that SRB caused pitting corrosion, which has been suppressed in the inhibitor-included systems.

Use of Trochodendron Aralioides Extract as Green Corrosion Inhibitor for Mild Steel in 1M HCl Solutions

Recently, there is an interesting discussion that has transpired around the world about the usage of plant extracts as corrosion inhibitors. We report that to control corrosion in mild steel (MS) specimens in a 1M HCl medium, Trochodendron aralioides (T. aralioides) extract was used as an economical green corrosion inhibitor. The various tests, namely, potentiodynamic polarization, weight loss measurements and electrochemical impedance spectroscopy (EIS) were performed to analyze the inhibition efficiency (IE) of the extract. The highest IE value of 96.42% was seen at 250 ppm, with the IE% increasing as the extract concentration increased. Potentiodynamic polarization suggests that T. aralioides plant extract acts as a mixed-type inhibitor. UV–visible (UV–Vis) and FT-IR spectroscopy were performed with the inhibitor to study the adsorption mechanism and surface analysis of the specimen, respectively. The results revealed that plant extracts form a protective film on the surface of the specimens, increasing inhibition and thereby reducing corrosion. Surface morphological studies such as AFM, EDX and SEM tests were performed in the presence and absence of the inhibitor with the results being analyzed by observing the surface of the metal.

Corrosion resistance and antibacterial activity of procyanidin B2 as a novel environment-friendly inhibitor for Q235 steel in 1 M HCl solution

Flavonoids, alkaloids, glucosides and tannins with good corrosion inhibition are the main natural components in plants. In this work, procyanidin B2 (PCB2), a natural flavonoid, was firstly isolated from Uncaria laevigata. Corrosion inhibition, chemical reactivity and adsorption of PCB2 on Q235 carbon steel were described by experimental and theoretical studies. The inhibition performance of PCB2 as a green corrosion inhibitor was evaluated by electrochemical and gravimetric tests. The binding active sites and activities thereof on the steel surface were illustrated by quantum chemistry, and the equilibrium configuration was predicted by molecular dynamics simulation. PCB2 exhibits good corrosion inhibition on Q235 steel over a wide temperature range. The electrochemical results show that PCB2 is a mixed inhibitor, and its inhibition efficiency increases with the addition of PCB2 concentration. Moreover, the protective film is formed on the steel and the active corrosion sites are blocked significantly by surface analysis. Additionally, the theoretical calculation proves a strong interaction between PCB2 molecule and carbon steel. Besides, the antimicrobial activity was also preliminarily studied. This suggests that PCB2 exhibits better antimicrobial activity against many Gram-positive and Gram-negative bacteria. As a novel green corrosion inhibitor and antimicrobial agent, PCB2 is worthy of further exploitation.

Characterization of crude oil degrading bacterial communities and their impact on biofilm formation

In the present study, produced water sample collected from the Indian crude oil reservoir is used to enrich the bacterial communities. The impact of these enriched bacterial communities on the biodegradation of crude oil, biofilm formation, and biocorrosion process are elucidated. A crude oil degradation study is carried out with the minimal salt medium and 94% of crude oil was utilized by enriched bacterial communities. During the crude oil degradation many enzymes including alkane hydroxylase, alcohol dehydrogenase, and lipase are playing a key role in the biodegradation processes. The role of enriched bacterial biofilm on biocorrosion reactions are monitored by weight loss studies and electrochemical analysis. Weight loss study revealed that the biotic system has vigorous corrosion attacks compared to the abiotic system. Both AC-Impedance and Tafel analysis confirmed that the nature of the corrosion reaction take place in the biotic system. Very less charge transfer resistance and higher corrosion current are observed in the biotic system than in the abiotic system. Scanning electron microscope confirms that the dense biofilm formation favoured the pitting type of corrosion. X-ray diffraction analysis confirms that the metal oxides formed in the corrosion systems (biotic). From the metagenomic analysis of the V3-V4 region revealed that presence of diverse bacterial communities in the biofilm, and most of them are uncultured/unknown. Among the known genus, Bacillus, Halomonas, etc are dominant in the enriched bacterial biofilm sample. From this study, we conclude that the uncultured bacterial strains are found to be playing a key role in the pitting type of corrosion and they can utilize crude oil hydrocarbons, which make them succeeded in extreme oil reservoir environments.