Schiff Base and Its Metal Complexes as Ecofriendly Pitting Corrosion Inhibitors on ASTM-A36 Low Carbon Steel in Corrosive Oil and Gas Well Treatment Fluids
Chimezie Peter Ozoemena,
Ekerete Jackson Boekom,
Ekaete Jacob Abai,
Essien Kufre Edet,
Inemesit Asuquo Akpan
Issue:
Volume 11, Issue 5, October 2023
Pages:
168-188
Received:
16 June 2023
Accepted:
14 August 2023
Published:
15 September 2023
Abstract: A high yield (74.63%) bidentate Schiff base ligand was synthesized from the condensation reaction of 4-aminophenol and 4-diethylamino-2-hydroxybenzaldehyde by the reflux method. Its transition metal complexes of Ni, Cu and Zn were prepared from the corresponding metal salts in methanol solution using the same procedure. The chemical structure of the synthesized Schiff base and its metal complexes was characterized by physicochemical, spectral analysis (FTIR and UV-Visible), and molar conductivity studies which revealed that the metal complexes were non electrolytic. Elemental analysis data for the Schiff base ligand and its metal complexes were used to confirm the general formula of the compound. The spectral data showed that coordination occurred through the azomethine nitrogen atom and the oxygen atom of the phenolic ring. The corrosion inhibition of Schiff base and its metal complexes was evaluated using potentiodynamic polarization (PDP), linear polarization resistance (LPR), and weight loss (WL) methods in acidic oil and gas well treatment fluid. The corrosive fluid was simulated using 1 M HCl solution. The results indicated that the compounds had a promising inhibitory effect on the corrosion of ASTM-A36 low carbon steel in the medium. The effectiveness of the inhibitors decreased with increasing time and temperature, but improved with increasing concentration of the inhibitors. The metal complexes showed a synergistic effect against Schiff base, with NiL1 having the maximum inhibition efficiency of 84.29%. The thermodynamic parameters revealed that the adsorption of the Schiff base and its complexes on the metal surface was spontaneous, endothermic and followed physical adsorption mechanism which conformed perfectly to the Langmuir adsorption isotherm. PDP measurements showed that the Schiff base and its metal complexes acted as mixed type inhibitors. The inhibition efficiency values obtained from the different techniques were comparable. SEM analyses of the corrosion product also confirmed the formation of a protective layer on the metal surface.
Abstract: A high yield (74.63%) bidentate Schiff base ligand was synthesized from the condensation reaction of 4-aminophenol and 4-diethylamino-2-hydroxybenzaldehyde by the reflux method. Its transition metal complexes of Ni, Cu and Zn were prepared from the corresponding metal salts in methanol solution using the same procedure. The chemical structure of th...
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Graphene-Like Biochar from Agricultural Waste for Cyanide Removal: Kinetic Study and Adsorption Isotherms
Djè Daniel Yannick,
Yacouba Zoungranan,
Kouassi Kouadio Dobi-Brice,
Ekou Lynda,
Ekou Tchirioua
Issue:
Volume 11, Issue 5, October 2023
Pages:
189-196
Received:
17 August 2023
Accepted:
7 September 2023
Published:
20 September 2023
Abstract: Cyanide is well-known for its toxic nature and is frequently employed in the mining and chemical industries. The discharge of wastewater containing cyanide into the natural environment in various forms poses a serious threat to human health and the ecosystem. In fact, its presence can inhibit mitochondrial function in humans, leading to headaches, dizziness, irregular heartbeat, convulsions, fainting, and even death. As part of the study, an approach was developed for removing cyanide through adsorption on an adsorbent that contains graphene. The process of collecting and converting agricultural waste led to the obtention of this adsorbent. Oil palm shells were used to prepare graphene-like biochar (GpB). The obtained GpB was characterized by X-ray diffraction and its ash content, humidity, and zero charge point pH were determined. The adsorption efficiency was assessed using parameters such as initial concentration, adsorbent mass, and contact time. According to the study, 0.1 g of GpB in 50 ml of cyanide solution resulted in a 97.39% elimination after 60 minutes of equilibrium time. The study of adsorption kinetics demonstrated that GpB's cyanide removal process is chemisorption, which follows the pseudo-second order kinetic model. The Freundlich and Temkin isotherms better describe the adsorption of cyanide on GpB, confirming the presence of multilayers and an exothermic reaction.
Abstract: Cyanide is well-known for its toxic nature and is frequently employed in the mining and chemical industries. The discharge of wastewater containing cyanide into the natural environment in various forms poses a serious threat to human health and the ecosystem. In fact, its presence can inhibit mitochondrial function in humans, leading to headaches, ...
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