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Reports on corrosion and microfouling analyses carried out in natural pondwater using mild steel under static condition. Corrosion rates were measured at regular intervals by weight loss and polarization techniques. The corrosion rate obtained by weight loss measurement was found to be less in the biotic system, but corrosion current obtained by polarization studies was higher in the biotic than abiotic system. Surface analysis by x‐ray diffraction indicates that bacteria with organic nutrients inhabited the corrosion to formation of surface film.

Corrosion-producing microorganisms have different physiology and include sulfate-reducing bacteria, iron oxidizers and magnesium oxidizers. Biocorrosion has been seen in various industries, especially the petrochemicals and oil industries. One proposal to solve this problem is the use of bacteriophages to treat the bacteria-caused corrosion. The aims of this study were isolation and identification of corrosion-producing bacteria from petroleum pipeline corrosion as well as finding their specific bacteriophages for phage therapy purposes.

The sample pipes with the corrosion were obtained from the Gandomkar petroleum pipeline station, Chaharmahal and Bakhtiari, Iran. For screening the corrosion-producing bacteria, the rusted pipe samples were cultured in a selective culture medium, manganese agar. The purified individual colonies were subjected to molecular examinations. For isolating bacteriophages from silversmithing workshops wastewater in Isfahan, whole plate titration methods and transmission electron microscopy were used to isolate and detect phages.

The cultivation of corrosion-based material on manganese agar after 18 hours incubation at 30°C resulted in the isolation of cream-colored colonies. The microscopic examinations showed Gram-negative coccobacilli. Based on molecular examinations, the isolated bacteria were identified as Stenotrophomonas maltophilia strain PBM-IAUF-2 with Genebank accession number of KU145278.1. The found bacteriophage was related to the Siphoviridae family of phages.

This paper is the first report of isolation and identification of corrosion-producing bacteria and its specific lytic phages from Gandomkar petroleum pipeline station, Chaharmahal and Bakhtiari, Iran. The biological procedures for preventing the microbial corrosion could be an asset and considered as a potential in the petroleum and industrial microbiology. Phage therapy is considered as one of the economical methods for reducing the biocorrosion.

To evaluate the effect of some tetrazole compounds as corrosion inhibitors of copper in HNO₃ at various temperatures.

1‐phenyl‐5‐mercapto‐1,2,3,4‐tetrazole (PMT) was selected as the best inhibitor among the tetrazole compounds tested. Gravimetric and electrochemical techniques were conducted.

PMT was an excellent inhibitor for copper in acid. Its efficiency attained 97.5 per cent and decreased slightly with temperature.

The inhibition efficiency increased with the concentration of PMT to reach 97.5 per cent at 10⁻³ M. Good agreement between the various methods explored was observed. Polarisation measurements also showed that PMT acted as a mixed inhibitor.

The efficiency of PMT increased with the concentration but decreased with rise of temperature in the 298‐333 K range. As such, PMT could be used in chemical cleaning and pickling processes.

The originality of this work was the finding of an efficient inhibitor (PMT) having a nearly 100 per cent efficiency.

The formulation consisting of 300ppm 1‐hydroxyethane‐1, 1‐diphosphonic acid (HEDP), 50ppm polyacrylamide (PAA) and 50 ppm Zn²⁺ offered 99 per cent corrosion inhibition and 99 to 99.9 per cent biocidal inhibition to mild steel in neutral aqueous environment containing 60ppm Cl‐ , a situation commonly encountered in cooling water systems. The nature of the protective film formed on the metal surface was analysed using X‐ray diffraction, UV‐visible reflectance, FTIR and luminescence spectra. The film was found to be luminescent and to consist of Fe²⁺ ‐HEDP complex, Fe²⁺ ‐PAA complex and Zn(OH)₂.

The term microbiologically induced corrosion (MIC) appears to be very closely related to the composition of the bio‐film which harbours the micro‐organism. Formation of an initial slimy layer on immersed metallic substrates is the rate‐controlling parameter of bio‐fouling, as uninterrupted undesirable growth of bio‐films occurs over this layer. To contain this bio‐film problem, formation of an adherent layer of toxic and inhibited corrosion product, that interacts with biofilm, could be exploited. Deals with the preliminary interactions of a few copper‐based alloys, with mildly toxic alkaloid class‐inhibitive compounds, in a simulated marine environment. It is assumed that the toxic and inhibited corrosion product and bio‐film interaction layer will interfere with the formation of the initial slimy cover on the immersed surface, responsible for bio‐fouling. It is seen that these alkaloid compounds exert a limited response on the inhibition of copper‐based alloys like monel. Brucine appears to be a more effective inhibitor for the monel surface. Pre‐oxidation of the uninhibited brass surface and also post‐oxidation of the inhibited surface appear to consolidate the corrosion product bio‐film‐inhibitor interaction layers, indicating the compatibility of these alkaloid compounds to the probable thermal strains to be encountered in engineering services. This indicates the possibility of using these compounds in heat transfer devices, like heat exchangers, where seawater is used as coolant.

The purpose of this paper is to set out a study of a Mannich base, which was synthesized and used as an acidizing corrosion inhibitor first, and to the corrosion inhibitor mechanism.

A Mannich base, 1-phenyl-3-(1-pyrrolidinyl)-propanone (PHPP), was synthesized with acetophenone, pyrrolidine and formaldehyde at pH = approximately 2-3. The structure of PHPP was characterized by elemental analysis and Fourier transform infrared spectroscopy (FTIR). The corrosion inhibition of PHPP on N80 steel in 15 per cent hydrochloric acid (HCl) was studied by weight loss method, scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDAX), and the adsorption behavior of PHPP on the surface of N80 steel was discussed.

The results showed that the inhibition efficiency reached to 99.8 per cent and corrosion rate was 2.65 g·m-2·h-1 at 0.6 per cent of PHPP concentration in 15 per cent HCl, which indicated that PHPP presented excellent corrosion inhibition performance. The results of SEM and EDAX analysis showed that PHPP could be absorbed on the surface of N80 steel. The adsorption process of PHPP on the surface of N80 steel was chemisorption. This process was spontaneous and obeyed Langmuir adsorption isotherm.

It was found that PHPP presented excellent corrosion inhibition performance, and it is practicable to enhance oil production in oilfield development as a oil-well acidizing inhibitor. The study results can provide theoretical guidelines for the development of the inhibitor.

This paper aims to focus on the basic principle of WO₃ gas sensors to achieve high gas-sensing performance with good stability and repeatability. Metal oxide-based gas sensors are widely used for monitoring toxic gas leakages in the environment, industries and households. For better livelihood and a healthy environment, it is extremely helpful to have sensors with higher accuracy and improved sensing features.

In the present review, the authors focus on recent synthesis methods of WO₃-based gas sensors to enhance sensing features towards toxic gases.

This work has proved that the synthesis method led to provide different morphologies of nanostructured WO₃-based material in turn to improve gas sensing performance along with its sensing mechanism.

In this work, the authors reviewed challenges and possibilities associated with the nanostructured WO₃-based gas sensors to trace toxic gases such as ammonia, H₂S and NO₂ for future research.

The purpose of this paper is to make people aware of organic corrosion inhibitors.

As it is a literature review paper, no specific method is used.

It has been found that plant extracts and oils show inhibition efficiency up to 98 percent, so it is certain that plant extracts and oils are effective corrosion inhibitors and can be successfully used at the industrial level.

Plant extracts and oils are also found to be non‐toxic, highly efficient, renewable and cheap. But less effort has been given towards the identification of which compound is active in the extract.

The paper shows detailed account of the inhibitors obtained from plants, which are used as natural corrosion inhibitors.

The purpose of this paper is to develop an eco-friendly corrosion inhibitor for mild steel in 1 M HCl.

A pharmaceutical drug acetyl G was investigated for its corrosion inhibition efficiency using weight loss method, potentiodynamic polarisation and electrochemical impedance spectroscopy.

The inhibition efficiency increased with increase in inhibitor concentration. Results from polarisation studies revealed mixed type of inhibition. Impedance studies, scanning electron microscopy and Fourier transform spectroscopy confirm the adsorption of inhibitor on the mild steel surface.

The drug acetyl G has sulphur and nitrogen atoms which effectively block the corrosion of mild steel and is non-toxic and has good inhibition efficiency.

This method provides an excellent, non-toxic and cost-effective material as a corrosion inhibitor for mild steel in acid medium.

Application of this drug as a corrosion inhibitor has not been reported yet in the literature. Replacing the organic inhibitors, this green inhibitor shows excellent inhibition efficiency. This is adsorbed excellently on the mild steel surface due to the presence of long chain and hetero atoms. Thus, the drug retards the corrosion reaction.

Bdellovibrio bacteriovorus is a gram-negative predatory bacterium which can potentially inhibit microbiologically influenced corrosion by preying on sulfate-reducing bacteria (SRB). However, no researches about the inhibition are reported according to the authors’ knowledge. The purpose of this paper was to investigate the Inhibition effect of B. bacteriovorus on the corrosion of X70 pipeline steel induced by SRB.

The effect of B. bacteriovorus on the growth of SRB was studied by measuring the optical density at 600 nm (OD600) and sulfate concentration in culture medium. X70 pipeline steel was used as the test material to investigate the anti-corrosion effect of B. bacteriovorus on SRB by conducting electrochemical analysis (including Tafel polarization curves and electrochemical impendence spectroscopy) and weight loss measurement.

B. bacteriovorus could inhibit the growth of SRB in culture medium by its predation on SRB, which led to decrease of OD600 value and increase of sulfate concentration. The results of electrochemical analysis indicated that B. bacteriovorus had positive inhibition efficiencies on SRB-induced corrosion of X70 pipeline steel. Moreover, corrosion rate of X70 pipeline steel was declined from 19.17 to 3.75 mg·dm-2·day-1 by the presence of B. bacteriovorus.

This is the first report about using B. bacteriovorus to inhibit the corrosion induced by SRB. Compared to other anti-corrosion methods, the microbial inhibition methods exhibit more considerable application value due to its low cost, high efficiency and non-pollution.