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Purpose The hollow copper wires of the generator are seriously corroded in cooling water. This paper aims to explore the mechanism of copper corrosion by thermodynamic calculation and kinetic experiments and to find out the precise pH range for preventing corrosion of copper in stator internal water and dual internal water cooled generators. Design/methodology/approach Thermodynamic and kinetic studies were carried out for the purpose of preventing the corrosion of hollow conducting copper wires in the internal cooling water. Thermodynamic calculation results demonstrate hollow copper wires electrochemically corroded by oxygen rather than acids (H+) and find out a precise anti-corrosion pH range. Kinetic experiments research on the effect of the pH value and oxygen concentration on corrosion and protection methods of copper in desalted water. Findings Research results demonstrate that, in the internal cooling water, hollow copper wires are electrochemically corroded by oxygen, rather than acids (H+). The method of preventing copper from corrosion in the desalted water is to control the pH value of the stator cooling water and the dual water inner cooling water between 7.86-8.86 and 7.86-9.26, respectively. Originality/value The thermodynamic calculation and potentiometric-pH diagram are used to obtain the accurate pH range of the inner cooling water and inner cooling water in the inner cooling water system. The kinetic experiments provide data support for the effect of temperature, pH value and oxygen concentration.

Pure chiral amines are crucial building blocks in the synthesis of some pharmaceutical drugs, agrochemical and other chemical compounds. Amine transaminases (ATAs) have been paid increasing attention as useful tools for efficient chiral-amine production. In particular, R-stereospecific ATA (R-ATA) is quite valuable and gains more benefit as industrial catalysts. Gabaculine is a common suicide inhibitor of ATAs. R-ATA is also inhibited by gabaculine. In order to guide the protein engineering of transaminases to improve substrate specificity and enantioselectivity, we carried out a crystal structural analysis of the R-ATA from Arthrobacter with the bound inhibitor gabaculine. Mechanistic studies and crystal structures have shown that (1) gabaculine binds to the aminotransferase enzyme, forming a Schiff base with the PLP cofactor; (2) the proton abstraction of this external aldimne yields an unstable intermediate which is then converted to extremely stable and irreversible m-carboxyphenylpyridoxamine phosphate (mCPP). Also the complex offers detailed insight into the structural basis for substrate specificity and enantioselectivity of the industrial application of R-ATAs.

Purpose – To study the inhibition effect and mechanism of the Momordica charantia extract (BM) to 20 A carbon steel in 5 per cent HCl. Design/methodology/approach – The weight loss, polarization curve, infrared spectrum (IR) analysis and X-ray photoelectron spectrum (XPS) analysis were carefully investigated to indicate the inhibition effect and mechanism of the BM to 20 A carbon steel in 5 per cent HCl. Findings – BM was composed of C, N and O. Functional groups such as N–H and C=O were found in BM. The inhibition efficiency increased with the increasing concentration of BM. BM behaved as a mixed-type inhibitor, and the inhibition of BM to 20 A carbon steel might be its adsorption through the coordinate covalent bonding among the lone pair electrons of N and O and the empty 3d orbits of Fe, and the adsorption on the surface of 20 A carbon steel obeyed the Langmuir isotherm equation. Research limitations/implications – The inhibition of the BM to 20 A carbon steel in 5 per cent HCl. Practical implications – BM could be used in 5 per cent HCl to prevent 20 A carbon steel from corrosion. Social implications – BM could be used in the chemical cleaning of the boilers to prevent the thermal equipments from corrosion. Originality/value – The inhibition effect and mechanism of the BM to 20 A carbon steel were studied by the weight loss, polarization curve, IR analysis and XPS analysis. BM was composed of C, N and O. Functional groups such as N–H and C=O were found in BM. BM behaved as a mixed-type inhibitor. The inhibition efficiency increased with the increasing concentration of BM, and the adsorption on the surface of 20 A carbon steel obeyed the Langmuir isotherm equation.

PurposeThe purpose of this paper is to study the inhibitive property of the mixture of an imidazole derivative (IMA) and benzotriazole (BTA) to the copper in deionised water.Design/methodology/approachStatic mass‐loss tests, electrochemical tests and surface analysis are used to study the inhibitive property of the mixture of an IMA and BTA to copper in deionised water.FindingsThere is a synergistic inhibitive effect on inhibition of the copper by the IMA and BTA in deionised water, and the mixture of the IMA and BTA is an effective inhibitor that mainly hinders the anode reaction.Practical implicationsThe mixture of the IMA and BTA is an effective inhibitor and can be used to prevent copper from corrosion in deionised water.Originality/valueThe mixture of the IMA and BTA is an effective inhibitor and should be suitable for use in the cooling water of an electricity generator unit to prevent corrosion of the copper conductors.

The inhibition mechanism and the relationship between the inhibition efficiency of para‐chlorobenzene nitriles on carbon steel in hydrochloric acid, and their molecular structure, were studied by microscopy and quantum chemistry calculations. The inhibition of carbon steel was achieved by chemisorption of the para‐chlorobenzene nitriles onto the surface of the carbon steel. The greater was the σN (absolute value) and the less the ELUMO value, the greater was the inhibition efficiency.

PurposeTo study the corrosion behavior and discuss the corrosion mechanism of No. 20 carbon steel in water in the presence of sulfide ions.Design/methodology/approachThe mass‐loss method, electrochemical tests and surface analysis were used to study the corrosion behavior and discuss the corrosion mechanism of No. 20 carbon steel in water in the presence of sulfide ions.FindingsGeneral corrosion occurred when No. 20 carbon steel was immersed in both test solutions (concentrated sample with S2− added to 0.8 mg/L, and pure concentrated sample with no S2− added). The presence of S2− in test solutions accelerated the corrosion rate of No. 20 carbon steel.Practical implicationsIn order to prevent No. 20 carbon steel in water with S2− from corroding, S2− must be removed.Originality/valueIt was found that the presence of S2− in test solutions accelerated the corrosion rate of No. 20 carbon steel in this paper. Therefore, when water containing sulfide ions is used as the source of make‐up water and cooling water, S2− in water must be removed to prevent the pipelines and facilities from corroding. This means the research results can offer theoretical guidelines for the prevention of pipelines and facilities in the power plant from corroding.