ISSN 2305-6894

2019, Vol. 8, Issue 2 (pp. 150-…)

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Relationship between the inhibition and antioxidant properties of the plant and biomass wastes extracts – A Review

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1 National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine. Ave Peremogy 37, Kiev, 03056, Ukraine
2 Ukrainian State Chemical-Engineering University, Gagarin Ave. 8, Dnipro, 49005, Ukraine

Abstract: Corrosion inhibitors are the only most widely applied method for corrosion protection of metallic materials and are of particular importance in industry. Nowadays, the synthesis of corrosion inhibitors using traditional multistep reactions is highly restricted because of the increasing demands of “green chemistry”. Plant materials and biomass wastes are ideal green candidatures to replace traditional toxic corrosion inhibitors. Literature survey reveals that different extracts of the plant and agro-food wastes contain naturally phytochemical compounds which have antioxidant properties have been effectively employing as sustainable inhibitors for the corrosion of different metals and alloys. Nevertheless, despite the numerous research papers, the reviews in which the correlation between the antioxidant/free radical scavenging activity of the extracts and their inhibition action is explained are not represented in the literature. This paper provides a brief overview of current knowledge in what kind of methods are used to estimate the antioxidant content, which classes of compounds provide higher antiradical activity and poses questions that we need to answer in order to use parameter of the antioxidant activity as a predictive index for performance evaluation of the plants/biomass wastes extracts as corrosion inhibitors. The conclusion is that no single mechanism of antioxidant actions and anticorrosive protection is operative in plant/wastes extracts. The high inhibitory efficiency is predicated on a number of complementary processes working holistically. By developing the theoretical basis and mechanism of action between the anticorrosive and antioxidant properties of plant extracts, it is possible to create predictive tools for selecting plant extract and further obtaining anti-corrosion protection based on it.

Int. J. Corros. Scale Inhib., , 2, 150-178 PDF (1 222 K)
doi: 10.17675/2305-6894-2019-8-2-1

Microencapsulation of corrosion inhibitors and active additives for anticorrosive protective polymer coatings

A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow, 119071 Russian Federation

Abstract: One of the most promising methods to improve the protective ability of coatings is the use of microencapsulated corrosion inhibitors (MCI) and active additives in their composition. Microencapsulation technology greatly simplifies the process of compounding the polymer protective coating and allows to isolate the active components from the reactive groups of polymer resins and hardener at the stage of curing, correctly form the polymer base of the coating and avoid the negative effect of the inhibitor on the adhesion of the coating to the protected substrate. The review discusses the main methods and techniques for producing micro- and nanocapsules. The basic requirements for the quality and complex characteristics of micro- and nanocapsulated corrosion inhibitors are presented. The advantages and disadvantages of capsules using solid materials, such as powders of natural and synthetic origin, carbon nanotubes, nanotubes based on clay materials and capsules with a liquid core and a polymer shell, for example, epoxy, epoxy, silicone resins, are noted. Description of the mechanism of transfer of the contents of microcapsules in the polymer base of the coating. The possibilities of “intelligent” microcapsules releasing the inhibitor when the pH level changes are considered. Examples of successful scientific and technical solutions for the manufacture and implementation of micro-and nanocapsulated corrosion inhibitors in coatings with specific materials used for the manufacture of microencapsulated corrosion inhibitors are given.

Int. J. Corros. Scale Inhib., , 2, 179-198 PDF (914 K)
doi: 10.17675/2305-6894-2019-8-2-2

The effect of some green inhibitors on the corrosion rate of Cu, Fe and Al metals

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1 Department of Chemical Engineering, Faculty of Engineering, Tafila Technical University, P.O.Box 179, Tafila, 66110, Jordan
2 Department of Chemistry and Chemical Technology, Faculty of Science, Tafila Technical University, P.O.Box 179, Tafila, 66110, Jordan
3 Department of Chemistry, Faculty of Science, Al-Isra University, Amman, Jordan
4 Department of Chemistry, Faculty of Science, Al-Balqa’ Applied University, Salt, Jordan

Abstract: Inhibition of metal corrosion is a very important and challenging issue environmentally. The use of corrosion inhibitors is an effective method to reduce the corrosion rate of several metals. In this regard, researchers have used a wide range of corrosion inhibitors for several decades to minimize the damages arising in corrosive environments. Density functional theory (DFT) calculations with B3LYP/6-31G* (d,p) level have been performed on APDTC, CMI, HPMA, PASP and PESA as a green source of environmentally friendly corrosion inhibitors for Cu, Fe and Al metals. Global quantum parameters of inhibitors and thermodynamic Gibbs function (∆Gads) of adsorption of metals have been calculated and used to investigate the efficiency of each corrosion inhibitor. Our results showed that APDTC exhibits the highest anti-corrosion efficiency among all compounds with Cu, Fe and Al metals showing remarkable inhibition efficiency with Cu comparing with Fe and Al. APDTC exhibit the highest electrophilicity index (ω) values compared to other inhibitors and it effect on the metals in the order: Cu > Fe > Al. The distinguished corrosion inhibition of APDTC is explained by its unique high electrophilicity power and Gibbs free energy of adsorption value on metal surface (∆Gads). The HOMO and LUMO gap (∆Egap) of the inhibitors increases in polymers in the order: HPMA > CMI > PESA > PASP > APDTC. These results show excellent agreement with recent published work.

Int. J. Corros. Scale Inhib., , 2, 199-211 PDF (758 K)
doi: 10.17675/2305-6894-2019-8-2-3

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