A pinboard by
Chinenye Chinwego

Prospective PhD Student, African University of Science and Technology, Abuja, Nigeria


This research focused on the suitability of a blend of plant extracts for CO2 corrosion inhibition.

Corrosion is a natural phenomenon which describes the deterioration of metals and alloys into their constituent atoms due to chemical reactions within their surrounding environment. The effects of corrosion in our daily lives are both direct, in that corrosion affects the useful service lives of our possessions, and indirect, in that producers and suppliers of goods and services incur corrosion costs, which they pass on to consumers. Preventative maintenance such as painting protects such items from corrosion. A principal reason to replace automobile radiator coolant every 12 to 18 months is to replenish the corrosion inhibitor that controls corrosion of the cooling system. Corrosion protection is built into all major household appliances such as water heaters, furnaces, ranges, washers, and dryers. Perhaps most dangerous of all is corrosion that occurs in major industrial plants, such as electrical power plants, chemical processing plants, manufacturing industries, oil and gas industries. The total annual estimated direct cost of corrosion in the U.S. is a staggering $276 billion, approximately 3.1% of the nation’s Gross Domestic Product. Corrosion inhibition is of great practical importance, being extensively employed in curtailing wastage of engineering materials. The use of inhibitors is quite varied often playing an important role in oil extraction and processing industries, heavy industrial manufacturing, and water treatment facility to minimize localized corrosion and unexpected sudden failures. Corrosion is most aggressive in industrial solutions containing chloride, bromide, hypochlorite ions, iodides, and fluorides, though the latter two are much less harmful. Gases such as carbon dioxide and hydrogen sulfide aggravate the problem and must be considered in proffering solutions. The application of corrosion inhibitors is an effective means of combating corrosion in aqueous and process industry environments but the high level of toxicity that most synthetic inhibitors possess is one of the reasons for the ongoing research work on natural inhibitors for corrosion control. These inorganic compounds may contain toxic phosphate; chromate and arsenic compounds that pose a high level of environmental risk thus, laws have been imposed to prohibit their use as corrosion mitigation substances. Thus, this research focused on studying the suitability of a blend of plant extracts for CO2 corrosion inhibition on carbon steel in 3.5%NaCl solution.


Corrosion inhibition effect of novel methyl benzimidazolium ionic liquid for carbon steel in HCl medium

Abstract: In the present investigation, the corrosion inhibition property of the newly synthesized3-(4-chlorobenzoylmethyl)-1-methylbenzimidazoliumbromide ([BMMB]+ Br−)ionic liquid on carbon steel was investigated in 1 M HCl solution using electrochemical studies. Polarization study revealed that [BMMB]+ Br− is a mixed type of inhibitor. The impedance to metal dissolution was increased not only with increasing inhibitor concentration but also with temperature. The diminished current amplitude waves obtained in the electrochemical noise analysis (ENA) technique implied high noise resistances thereby indicating the formation of passive inhibitor layer. Adsorption of [BMMB]+ Br− ionic liquid on carbon steel was spontaneous and followed a Langmuir adsorption isotherm. The surface examination of the coupons before and after engrossed in inhibited medium was analyzed using Attenuated total reflectance – Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electrochemical microscope with energy dispersive X-ray (SEM/EDX) studies and confirmed that the surface of carbon steel was protected from corrosion by the adsorption of [BMMB]+ Br− ionic liquid. Thermodynamic properties revealed that [BMMB]+ Br− has both physical and chemical adsorption behavior. In addition, density functional theory (DFT) calculations were carried out to give atomic level understandings to the experimental results by deducing the electronic properties of inhibitor in proportion to inhibition efficiency in aggressive medium.

Pub.: 08 Jun '16, Pinned: 27 Sep '17

The inhibition of carbon-steel corrosion in seawater by streptomycin and tetracycline antibiotics: An experimental and theoretical study

Abstract: Publication date: 15 December 2016 Source:Desalination, Volume 400 Author(s): Maryam Dehdab, Zahra Yavari, Mahdieh Darijani, Afshar Bargahi The corrosion inhibition of Tetracycline and Streptomycin on the carbon-steel, Fe (110), in seawater was evaluated using weight loss, Tafel polarization, electrochemical impedance spectroscopy and SEM morphometric methods. The surface adsorption of inhibitors follows the Langmuir adsorption isotherm and acts as spontaneous mixed-type corrosion inhibitors on the carbon-steel surface. The related thermodynamic parameters (Ea, Kads, ∆Gads, ∆H≠ and ∆S≠) were evaluated and the interaction energy for Streptomycin was more than the Tetracycline. The SEM morphometric showed a good protection effect of inhibitors on carbon-steel in the presence of seawater and this was more efficient for Streptomycin. To emphasize the further insight into the efficiency of inhibitors, the Quantum chemical analysis and molecular dynamics simulations were used to find the most stable configuration and adsorption energies for inhibitors on the carbon-steel surface. The theoretical quantum chemical data such as EHOMO, η, χ, molecular surface area, MV, μ, α and ΔN were in agreement with inhibition efficiencies (IE %) that were obtained experimentally. Also, the molecular dynamics simulation showed the most stable configuration and adsorption energies of Streptomycin and Tetracycline on the carbon-steel and this follows the order of Streptomycin>Tetracycline, as verified by the experimental data.

Pub.: 19 Sep '16, Pinned: 27 Sep '17

Carbon dioxide corrosion of carbon steel and corrosion inhibition by natural olive leaf extract

Abstract: The corrosion of carbon steel in carbon dioxide saturated chloride carbonate solution with and without olive leaf extract at 25 °C and 65 °C has been studied by linear polarization resistance technique, electrochemical impedance spectroscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. In the absence of olive leaf extract, the corrosion products created under the testing conditions within 24 h at both testing temperatures have no significant protective properties. Measurements for uninhibited systems showed high corrosion current densities and low polarization resistances of carbon steel. Both linear polarization resistance technique and electrochemical impedance spectroscopy measurements reveal that olive leaf extract inhibits the carbon steel corrosion. The addition of a low-concentration olive leaf extract decreases corrosion current densities, increases charge transfer and polarization resistance, resulting in more uniform and smoother steel surfaces. These effects are attributed to the adsorption of olive leaf extract on the carbon steel surface.Die Korrosion von Kohlenstoffstahl in Kohlendioxid gesättigter chloridhaltiger Karbonatlösung gesättigt mit und ohne Olivenblattextrakt bei 25 °C und 65 °C wurde durch Messung des linearen Polarisationswiderstands, elektrochemische Impedanzspektroskopie, Rasterelektronenmikroskopie und Fourier-Transformations-Infrarot-Spektroskopie untersucht. In Abwesenheit von Olivenblattextrakt bilden die Korrosionsprodukte unter den Testbedingungen innerhalb von 24 h bei beiden Versuchstemperaturen keine wesentlichen Schutzeigenschaften aus. Die Messungen der inhibierten Systeme ergeben hohe Korrosionsstromdichten und niedrige Polarisationswiderstände. Sowohl die Ergebnisse aus Polarisationswiderstandsmessungen als auch der elektrochemischen Impedanzspektroskopie dokumentieren, dass Olivenblattextrakt die Korrosion von Kohlenstoffstahl hemmt. Die Zugabe von Olivenblattextrakt in niedriger Konzentration verringert Korrosionsstromdichten, erhöht den Ladungstransfer und Polarisationswiderstand und führt zu gleichmäßigeren und glatteren Stahloberflächen. Diese Effekte sind auf die Adsorption des Olivenblattextrakts auf den Kohlenstoffstahloberflächen zurückzuführen.

Pub.: 17 Feb '17, Pinned: 27 Sep '17