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Reusing expired streptomycin and neomycin drugs as potential corrosion inhibitors for high brass alloys in NaCl solution: quantum, chemical, surface and electrochemical investigations

Research Abstract

Although drugs are essential for humans, they are perilous for the ecosystem when disposed of improperly. There are challenges in reusing them for other useful purposes, most notably as corrosion inhibitors; corrosion inhibition is an important industrial and economic aspect of protecting metals and the environment. Copper alloys are widely used in outdoor applications, especially in casting decorative items, but they have shortcomings in corrosion resistance. Herein, the ability of two expired drugs, streptomycin (I) and neomycin (II), to resist the corrosion of a high Cu–Zn alloy in a 3.5% NaCl environment was studied in detail via electrochemical, gravimetric and microscopic techniques as well as theoretical calculations. The electrochemical results showed that there was an increase in the corrosion rate of the examined alloy with increasing [NaCl]. The addition of 500 mg L−1 of the tested drugs strongly inhibited alloy corrosion, and the inhibition efficiencies (% IEs) reached 87.4% and 91.6% with drugs I and II, respectively. The obtained gravimetric outcomes indicated that the values of % IEs were augmented with increasing drug dosages, while they decreased as [NaCl] and solution temperature increased. The higher % IEs were attributed to the strong adsorption of the drugs on the brass surface. This adsorption was suggested to be physical and obeyed the Langmuir adsorption isotherm. Polarization assessments indicated that these drugs were mixed-type inhibitors with an anodic priority. All thermodynamic/kinetic parameters were determined through full adsorption assays, and the possible inhibition mechanism was proposed. Computational methods provided further support and clarification of the inhibition mechanism of these drugs. All results of the applied techniques were in excellent conformity with each other and with the employed computational methods.

Research Authors
Ahmed Fawzy, Arafat Toghan, Areej Al Bahir, Emad M. Masoud, Magdi E. A. Zaki, Minghua Huang, Ahmed A. Farag, H. S. Gadow
Research Date
Research Department
Research Journal
RSC Advances
Research Member
Research Pages
39123 –39147
Research Publisher
ACS
Research Vol
15
Research Year
2025

Unravelling Adsorption and Interaction of Synthesized Chlorinated Cyclic Imide Derivative on the Corrosion of C‑Steel in H2SO4 Solution: Experimental Control and Mathematical Calculations

Research Abstract

 Steel corrosion is a serious problem not only economically but also has a negative impact on our safety. In this report, the inhibitory efficiency of the synthetic chlorinated cyclic imide named f (CCIBA) on the corrosion of carbon steel (CS) in 1.0 M sulfuric acid solution was explored using different experimental and theoretical methods. Weight loss and electrochemical measurements were used to determine the inhibition efficacy (%IE) of CCIBA. The findings revealed that with the increase of CCIBA concentration, the corrosion rate omitted and the %IE value increased to 93%. While with the increase of temperature, the CS corrodes strongly. The higher values of %IE were proposed to be due to strong adsorption of the CCIBA molecules on the CS surface and such adsorption was mainly chemicalinits natureand wasconsistentwiththe Langmuiradsorption isotherms.Polarizationcurves revealed thatCCIBAbehaved as a mixed-type inhibitor. It was also shown that icorr values decreased sharply from 5930 to 417μA cm−2 with the addition of 29 × 10−6 M CCIBA. Impedance measurements demonstrated that raising the CCIBA concentration increased charge transfer. The coefficient values of kinetics and thermodynamics were calculated. Based on the data obtained, the inhibition mechanism was proposed. Computational predictions are in good agreement with experimental measurements.

Research Authors
Arafat Toghan, Ahmed Fawzy, Sami A. Al-Hussain, Emad M. Masoud, Hend S. Gadow
Research Date
Research Department
Research Journal
ACS Omega
Research Member
Research Pages
46593-46611
Research Publisher
ACS
Research Year
2025

Assessing the inhibition performance of newly synthesized acridine-pyrazole derivatives on the corrosion of carbon steel in HCl solution: experimental and theoretical approach

Research Abstract

Herein, Two new acridin-pyrazole Schiff bases, (E)-2-phenyl-5-propyl-N-(1,2,3,4-tetrahydroacridin-9-yl)-2,4- dihydro-3H-pyrazol-3-imine (APS-1) and (E)-5-(methoxymethyl)-2-phenyl-N-(1,2,3,4-tetrahydroacridin-9-yl)- 2,4-dihydro-3H-pyrazol-3-imine (APS-2), were synthesized and their anticorrosion activities for carbon steel (CS) were evaluated in 1 M HCl solution. Atomic Force Microscopy (AFM), mass loss (ML), potentiodynamic polarization (PDP) and electrochemical impedance measurement (EIS) were used to investigate their surface, and inhibition performance (η %). ML measurements of APS-1 and APS-2 (5 mM) showed η% values of 93.3% and 95.0% at 298 K, respectively. Adsorption studies confirmed that they have physical-chemical interactions and obeyed the Langmuir model. PDP measurements showed that they had a mixed nature. EIS experiments revealed that they increased the resistance of CS to charge transfer while simultaneously reducing the double layer capacitance. Theoretical calculations using density functional theory (DFT) and molecular dynamics (MD) simulation were also performed to investigate the adsorption patterns of the synthesized compounds on the Fe (110) surface. The mechanism of inhibition is proposed and elucidated. The experimental measurements were in complete agreement with the theoretical predictions.

Research Authors
Arafat Toghana, Ahmed Fawzy, Abdalrhman G. Al-Gamal, Ahmed A. Farag
Research Date
Research Department
Research Journal
Journal of Molecular Structure
Research Member
Research Pages
1-16
Research Publisher
Elsevier
Research Vol
1346
Research Year
2025

Corrigendum to “Corrosion inhibition performance of new Schiff base cyclohexanamine derivatives on C-steel in 1 M HCl solution: Electrochemical, chemical, surface and computational explorations” [Inorg. Chem. Commun. 163 (2024) 112339]

Research Authors
Ahmed A. Farag, AbdulAziz A. Alayyafi, Hanan Alhussain, Ahmed Fawzy, Emad M. Masoud, Arafat Toghan
Research Date
Research Department
Research File
Research Journal
Inorganic Chemistry Communications
Research Member
Research Publisher
Elsevier
Research Vol
174
Research Year
2025

Mathematical, electrochemical, spectroscopic and microscopic monitoring of the adsorption effect of expired drugs on zinc corrosion in 3.5% NaCl solution

Research Abstract

Because of its unique properties, zinc is widely used in many industries, including medical devices, electronics, and automotive components, but it is susceptible to corrosion, especially in salty environments. In this context, the inhibitory efficacy of two environmentally friendly expired drugs, gatifloxacin (Gat) and levofloxacin (Lev), on zinc corrosion in 3.5 % NaCl solution was investigated using several techniques at different temperatures. Kinetic and thermodynamic evaluations confirmed that the adsorption strength of these compounds on the metal surface plays an effective role in their inhibitory capacity, and this certainly depends on their chemical structure. The inhibition efficiencies (% IEs) were calculated to be 87 % and 89 % for Gat and Lev using 500 mg/L of drug and at 298 K, respectively. Potentiodynamic polarization (PDP) studies have classified these drugs as anodic-type inhibitors. Adsorption assessments have shown that it is a physical process following the Langmuir isotherm. Electrochemical impedance spectroscopy (EIS) experiments have demonstrated good adhesion and stability of the protective film on the metal surface resulting from the adsorption of these compounds. Inhibition mechanisms have also been provided. Response surface methodology (RSM) analysis was used to analyze the data and predict the response. The experimental results of all the techniques used and the statistical and computational analysis were in remarkable agreement with each other.

Research Authors
Arafat Toghan, Omar K. Alduaija, Nada Alqarni, Emad M. Masoud, Hanan Alhussain, Ayman M. Mostafa, Ahmed A. Farag, Ahmed Fawzy
Research Date
Research Department
Research Journal
Results in Chemistry
Research Member
Research Pages
1-14
Research Publisher
Elsevier
Research Vol
13
Research Website
https://doi.org/10.1016/j.rechem.2024.102006
Research Year
2025

Sustainable biohydrogen production from banana peels using microbial fermentation

Research Abstract

Background

Global energy demand and environmental concerns are driving the search for sustainable alternatives. Banana peels, which account for 30–40% of the 139 million tons of bananas produced annually, are rich in organic matter and offer a promising source for biofuel production. To investigate this potential, experiments were conducted to assess their suitability for biofuel generation.

Methods

Microbial conversion of banana peels into hydrogen and acetone-butanol-ethanol (ABE) was investigated through anaerobic fermentation and enzymatic hydrolysis. Various inocula were tested for anaerobic digestion. Peels concentration kinetics were analyzed, and bacterial isolates were screened for their ability to degrade phenolic compounds, produce cellulase and pectinase, and generate biofuels. The most efficient isolate was identified using 16 S rRNA sequencing.

Results

Findings demonstrate that banana peels have a high volatile solids content of 93.7%, a rich carbohydrate profile (550 mg/g reducing sugars, 133.25 mg/g total carbohydrates), and a balanced C/N ratio of 21.5, making them a promising substrate for biofuel production and waste management. In evaluating inoculum performance, chicken manure proved to be the most effective inoculum, producing 846.6 mL/L of hydrogen with a bacterial count of 12.67 × 10⁵ CFU/mL, followed by cow dung (283.3 mL/L of hydrogen). Soil inoculum did not result in hydrogen production despite microbial activity. Furthermore, the optimal hydrogen production was achieved at a 20% (w/v) banana peels concentration, reaching 1400 mL/L, with higher concentrations (40%) showing inhibition. The Gompertz model confirmed the peak performance at 20% concentration (Hₘₐₓ = 1330 mL, Rₘₐₓ = 130 mL/h, R² = 0.99). Among bacterial isolates, isolate W26 (Bacillus stercoris, 99.93% 16 S rRNA identity) from cow rumen produced the highest hydrogen (1750 mL/L), while W17 excelled in ABE production (1.033 g/L, primarily ethanol). Bacterial isolates W17, W18 and W22 demonstrated cellulase activity, while W13, W20, W23 and W24 exhibited pectinase activity, with W26 showing both. Tolerance to phenolic compounds varied among isolates, with gallic acid, ferulic acid, quercetin, and tannic acid supporting growth in most isolates, unlike pyrogallol. Collectively, these findings highlight the potential of banana peels for sustainable biofuel production, with chicken manure and Bacillus stercoris as the optimal inoculum and isolate, respectively.

Conclusions

Based on these findings, banana peels are a promising biofuel substrate due to their high carbohydrate content and favorable C/N ratio. Chicken manure and bacterial isolate W26 (Bacillus stercoris) were found to boost hydrogen production at a 20% peels concentration, yielding 1400 mL/L and 1750 mL/L, respectively. Some isolates exhibited cellulase, pectinase, and ABE production capabilities, with W17 achieving the highest ethanol yield of 0.930 g/L. These results highlight the viability of banana peels for eco-friendly bioenergy production and effective waste management.


 

Research Authors
Mohamed Hemida Abd-Alla, Shymaa Ryhan Bashandy, Wafaa Abdelnaser Sleem & David Mamdouh Khalaf
Research Date
Research Journal
BMC Biotechnology
Research Pages
16
Research Publisher
Springer Nature
Research Rank
Q2
Research Vol
26
Research Website
https://link.springer.com/article/10.1186/s12896-025-01080-3
Research Year
2026

Prediction of certain conjugate convective flow of a micropolar nanofluid in an inclined enclosure with the Lorentz force and porous medium by virtue of the artificial neural networks

Research Abstract

: Inclinedsquarecavitiesplayacritical role inengineeringapplications,partic ularlyinthermalmanagement,energystorageandelectroniccooling,whereinclinationangles in°uence convectiveheat transfer.This studyexamines conjugate convectiveheat transfer withinaninclinedsquarecavity¯lledwithmicropolarnano°uidsunderatiltedLorentzforce usinga two-phasenano°uidmodel.The systemincludes aheat-generatingporousmedium underthermalnonequilibrium, introducingcomplexdynamics.Factorssuchasthermalbuoy ancy,°uid{solidheattransfercoe±cientandmicropolar°uidpropertiesareanalyzedfortheir impact onheat transfer e±ciency.Methods:The studyuses the¯nitedi®erencemethod (FDM) to solvenonlinear equations governingconvective°owandheat transfer.Physical parameters,includingthermalbuoyancy,micropolarpropertiesandthicknessofthesolidwalls,

Research Authors
M. A. Mansour, Thirupathi Thumma, Sameh E. Ahmed, S. R. Mishra, M. A. Y. Bakier, Eman F. Mohamed, Zahra Hafed, and Muflih Alhazmi
Research Department
Research Journal
International Journal of Modern Physics B
Research Year
2025
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