Chemistry
Shams A. Naji; Rana Afif Anaee; Sadeer M. Majeed
Abstract
The addition of expired drugs as green inhibitors takes high attention as an alternative material compared with other expensive, toxic, non-available chemical inhibitors. In this study, the Dexon drug was suggested as a green inhibitor for commonly used carbon steel in (3.5% NaCl solution) within a temperature ...
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The addition of expired drugs as green inhibitors takes high attention as an alternative material compared with other expensive, toxic, non-available chemical inhibitors. In this study, the Dexon drug was suggested as a green inhibitor for commonly used carbon steel in (3.5% NaCl solution) within a temperature range of 303 to 333 K. Corrosion/inhibition investigation was done by potentiostatic analysis to record the corrosion potential, corrosion current density, and Tafel slopes for the added four concentrations (4, 20, 40 and 60 mL/L) of the drug. The polarization resistances and inhibition efficiencies reached the highest value of (25.86×10-3 Ω.cm2) and (95.57%) respectively for 60 mL/L at 303 K. For examination of inhibited surface, Infrared spectrum, electron scanning microscopy, and atomic force microscopy. These techniques confirmed effective surface coverage by the adsorbed drug, forming a (Fe²⁺ ‒ Dexamethasone) complex. This was further supported by a reduction in surface roughness from 270.8 nm to 24.96 nm following inhibition using a concentration of 60 mL/L. Theoretical calculations indicated that the adsorption process was physical, spontaneous, less disordered, and exothermic. Additionally, quantum data, including HOMO and LUMO analyses, demonstrated the high adsorption capability of the Dexamethasone molecule on the steel surface. The results showed an energy gap of 3.43 eV, reflecting the molecule’s soft nature and the release of energy during the adsorption process.
Chemistry
Thekra Abd Alkarim; Khalida F. Al-Azawi; Rana Afif Anaee
Abstract
The investigation of the efficiency of two expired drugs, including Spiramycin and Isosorbide dinitrate, was done as corrosion inhibitors for aluminum in 0.1M HCl medium using the electrochemical method by Potentiostst at four temperatures (293, 303, 313, and 323 K) and 200 ppm as constant concentration ...
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The investigation of the efficiency of two expired drugs, including Spiramycin and Isosorbide dinitrate, was done as corrosion inhibitors for aluminum in 0.1M HCl medium using the electrochemical method by Potentiostst at four temperatures (293, 303, 313, and 323 K) and 200 ppm as constant concentration for each drug. The results showed that these drugs gave good efficiencies equal to 98.836% and 94.285 % for Spiramycin and Isosorbide dinitrate at 293 K, respectively, by adsorption process on the metallic surface. They act as mixed-type inhibitors due to shifting corrosion potential either to active or noble direction. The corrosion data were measured and debated, where the corrosion current density was decreased after adding expired drugs to the corrosive medium due to inhibiting the cathodic and anodic reactions (i.e., the dissolution and reduction reactions). Using SEM exam, the inhibited surface of specimens was characterized to confirm the coverage of the surface by drug molecules. The adsorbed layer by Spiramycin was better than that by Isosorbide dinitrate. Also, the Fourier transform infrared spectra were used to limit the active site attracted to the surface by adsorption that confirmed the attraction by hydroxyl and nitro groups, as illustrated by the mechanism of inhibition. In addition, the antibacterial activity of the inhibitors against some types of bacteria was tested to confirm the formation of an inhibition zone against bacteria. The quantum chemical parameters exhibited a good correlation with the inhibition efficiency.
