Bulletin of the Chemical Society of Ethiopia

Polyphenol contents of ten most widely cultivated and consumed vegetables in Ethiopia

2025-03-21T07:06:39+00:00

Vegetables are the fresh and edible portions of herbaceous plants. Vegetables have been used as a source of food due to their abundant bioactive chemical contents. This study was aimed to determine phenolics contents of ten most widely consumed vegetables (beetroot, cabbage, cauliflower, carrot, chili, eggplant, lettuce, potato, Swiss chard, and tomato) by UV-Visible spectrophotometry. The highest level of bound phenolics was found in cabbage (401 mg GAE/100 g) whereas the lowest level was found in tomato (92 mg GAE/100 g). Higher total phenolic contents were found in the extracts of cabbage (3171 mg GAE/100 g), chili (2006 mg GAE/100 g), Swiss chard (1313 mg GAE/100 g), lettuce (1160 mg GAE/100 g), eggplant (1143.2 mg GAE/100 g) and cauliflower (1086 mg of GAE/100 g). While potato had the lowest total polyphenol contents (217.5 mg GAE/100 g) among the studied vegetables. Presence of substantial amounts of total phenolics in vegetables is responsible for their effective antioxidant potency. Therefore, there is a high potential for the use of vegetables as a health promoting and disease preventing source.

KEY WORDS: Vegetables, Polyphenols, Gallic acid, Ethiopia

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1029-1041.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.1

The influence of pH on the properties of chemical bath deposited nickel sulfide films

2025-03-21T07:12:38+00:00

Nickel sulfide thin films have been prepared on a microscope glass substrate through the chemical bath deposition technique. In this study, nickel sulfate and sodium thiosulfate were utilized to supply nickel ions and sulfide ions, respectively. The surface characteristics of the prepared films were studied with atomic force microscopy. For the first time, X-ray photoelectron spectroscopy and Raman spectroscopy are used to investigate structural information, electronic states and the chemistry of material surfaces. The films produced at pH 4 and pH 5 (acidic environment) are smooth and devoid of cracks, displaying consistent morphology and uniform surface as indicated by atomic force microscopy findings. These properties might improve the efficiency of solar cells when compared to samples made with different pH values.

KEY WORDS: Photovoltaic, Renewable energy, Energy efficiency, Thin films, Nickel sulfide

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1043-1055.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.2

Enhancing efficiency and thermal stability of amino benzotriazole fluorescent dye via ligand-to-metal charge transfer reactions for solar cell applications: A comprehensive compositional and spectroscopic study

2025-03-21T07:15:45+00:00

Herein in this study, we have synthesized three new iron(III), chromium(III), and vanadium(III) transition metal complexes of the 2-(2'-hydroxy-5'-phenyl)-5-aminobenzotriazole (hpabt) fluorescent dye. Infrared, and ultraviolet-visible spectral examinations, as well as elemental analysis, magnetic susceptibility, and molar conductivity analyses, all supported the structural interpretations. The complexes have a stoichiometry of 1:1 (M³⁺: hpabt) based on the analytical, spectroscopic, and thermal data. The molar conductance measurements showed that the chloride ions inside the coordination sphere and all the metal chelates are non-electrolytes. These three complexes decomposition processes are examined and their thermal stabilities were examined using thermogravimetric (TGA) analysis. Activation entropy (ΔS*), activation enthalpy (ΔH*), free energy of activation (ΔG*), pre-exponential factor (A), and energy of activation (E*) are examples of kinetic parameters that have been recorded. The surface morphology of iron(III), chromium(III), and vanadium(III) complexes were studied by scanning electron microscopy (SEM). The 2-(2'-hydroxy-5'-phenyl)-5-aminobenzotriazole photostability as a fluorescent dye and its synthesized metal complexes doped in polymethyl methacrylate (PMMA) were subjected to UV-Vis. light, and the absorption spectra changed at various points during the exposure period.

KEY WORDS: Benzotriazole, Fluorescent dye, Transition metals, Thermal stabilities, Spectroscopic analyses

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1057-1070.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.3

Synthesis, spectral characterization and biological studies of Co(II) complexes with Schiff bases derived from sulpha drugs

2025-03-21T07:20:20+00:00

This study reports the synthesis, spectral characterization, and antimicrobial evaluation of a cobalt(II) complex, [Co(L)₂Cl₂], derived from 4-amino-N-(5-methyl-1,2-oxazol-3-yl)benzenesulfonamide and 2-hydroxy- benzaldehyde. The complex was synthesized via refluxing the Schiff base ligand with Co(II) chloride in ethanol. Spectroscopic and analytical techniques (molar conductance, elemental analysis, IR, UV-Vis, ¹H and ¹³C NMR, and mass spectrometry) confirmed complex formation and bidentate coordination through azomethine nitrogen (-CH=N) and phenolic oxygen (-OH). Electronic spectra and magnetic moment data suggested an octahedral geometry. The electrochemical behavior of the complex was analyzed using cyclic voltammetry, revealing quasi-reversible Co(II)/Co(I) redox behavior. Antimicrobial activity was evaluated using the disc diffusion method against Staphylococcus aureus, Proteus vulgaris, and Candida albicans. The Co(II) complex exhibited enhanced antibacterial and antifungal activity compared to the free Schiff base, attributed to increased lipophilicity and better microbial membrane interaction. Minimum inhibitory concentration (MIC) studies further confirmed its effectiveness. These findings highlight the potential of Schiff base Co(II) complexes as promising antimicrobial agents, supporting further exploration for biomedical applications.

KEY WORDS: Schiff base, Co(II) complex, Elemental analysis, Spectral characterization, Redox behavior, Fluorescence, Antibacterial assay, Antifungal activity and MIC studies

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1071-1082.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.4

Chracterization of the complexation between indium(III) and zirocnium(IV) ions with the drug procaine: Spectral analysis, thermal properties, and microscopic imaging

2025-03-21T07:24:39+00:00

This paper investigates the complexation behavior of the drug procaine towards forming stable metal-based complexes. The study examines the chemical reaction between procaine (PC) and two metal ions (In³⁺ and Zr⁴⁺). Controlling the temperature at 70 °C, the pH at approximately 8.5, and the stoichiometry at 1:3 for In³⁺ ion and 1:2 for Zr⁴⁺ ion, the reaction generated white, stable PC-In and PC-Zr complexes. To provide a comprehensive understanding of the structural, compositional, morphological, and thermal properties of the formed metal-procaine complexes, a variety of physicochemical techniques were employed to thoroughly characterize the synthesized complexes, including CHN elemental analysis, conductivity, ultraviolet/visible and Fourier-transform infrared spectroscopies, powder X-ray diffraction, transmission electron microscopy, and thermogravimetry. The study reveals that the manufactured complexes of In³⁺ and Zr⁴⁺ can be represented by the formulae [In(PC)₃(H₂O)₃].Cl₃ and [ZrO(PC)₂(H₂O)₂].Cl₂.4H₂O, respectively. These formulas correspond to the overall compositions of C₃₉H₆₆N₆Cl₃O₉In, and C₂₆H₅₂N₄Cl₂O₁₁Zr, respectively. The high-quality and well-focused TEM images demonstrate that the complexes possessed a uniform and well-structured morphology. The investigation of the complexation behavior of procaine with In³⁺ and Zr⁴⁺ ions provide valuable insights into the formation and properties of these stable complexes, which can have potential applications in the pharmaceutical and biomedical fields.

KEY WORDS: Drug procaine, Metal ion, Spectral analysis, Thermal decomposition, TEM

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1083-1094.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.5

Synthesis, spectoscopic, thermal, and mophological studies of metal-based complexes derived from the reaction of cinchonine with manganese(II), nickel(II), and zinc(II) ions

2025-03-21T07:28:57+00:00

This work involved the meticulous synthesis of three metal-based complexes of the naturally occurring compound cinchonine (abbreviated as CN), which belongs to the Cinchona alkaloids family and exhibits potent antimalarial properties. Studying these metal-based complexes is crucial, as it enhances our understanding of cinchonine's biological characteristics. The CN complexes were carefully prepared by dissolving the CN ligand in methanol and the investigated Mn(II), Ni(II), and Zn(II) metal ions in deionized water. The chemical reactions were carried out at a controlled temperature of 70 °C, a 1:1 (CN to metal ion) stoichiometry, and a pH of approximately 8.5. These conditions yielded the desired CN-Mn, CN-Ni, and CN-Zn complexes, which were subsequently characterized using various physicochemical techniques. The comprehensive characterization provided detailed insights into the structural, thermal, and morphological properties of the complexes. The results indicate that the CN complexes with Mn(II), Ni(II), and Zn(II) can be represented by the formulas [MnCN(H₂O)₃Cl₂], [NiCN(H₂O)₅]·Cl₂·2H₂O, and [ZnCN(H₂O)₅]·Cl₂·4H₂O, respectively. The IR spectral data suggests that the CN ligand coordinated with the Mn(II), Ni(II), and Zn(II) ions through the nitrogen lone pair electrons of the C=N group. The high-quality and well-focused TEM images demonstrate the complexes possessed a uniform and well-structured morphology.

KEY WORDS: Cinchonine, Metal ions, Spectroscopic analyses, Thermal characterization, Electron microscopy

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1095-1108.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.6

Synthesis, spectroscopic, thermal, biological activities studies for Ni(II),Cu(II) and Zn(II) complexes with phthalohydrazide derived ligand and evaluation as antioxidants

2025-03-21T07:33:01+00:00

The present article discusses the synthesis of tetradentate Schiff base complexes formed by the condensation reaction of 2-hydroxy benzaldehyde and phthalohydrazide. The ligand (LH2) was detected using FT-IR spectra, ¹H, ¹³C-NMR, UV-Vis spectroscopy, elemental microanalysis CHN, and mass spectrometry. The obtained solid complexes have been assessed using physicochemical and spectroscopic techniques, including UV-Vis, FT-IR, nuclear magnetic resonance (¹H-NMR, ¹³C-NMR), mass spectrometry, thermal gravimetric analysis (TGA), and atomic absorption, in addition to complex conductivity and magnetic moment measurements. The infrared results demonstrated that ligands functioning as tetradentate ligands are chelated to metal ions via the phenolic oxygen and nitrogen of the azomethine group. Specific metal ions join with chloride ions (Cu⁺², Zn⁺²) to reach their coordination numbers. The generated compounds' antibacterial effect in vitro was measured towards Candida albicans as a fungal species, Gram-positive Bacilla and pseudomonas, and Gram-negative Staph and E. coli using the agar well diffusion technique. The ligand generated an octahedral geometry around the (Cu⁺² and Zn⁺²) and a tetrahedral form around the Ni⁺² metal ion, per the measurement and spectroscopic tests. Ascorbic acid is used as a standard in the phosphomolybdate technique to assess the antioxidant activity of the ligand and complexes.

KEY WORDS: Antioxidant activity, Phosphomolybdate, Tetradentate ligand, Coordination number, Condensation reaction

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1109-1118.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.7

Synthesis, spectroscopic studies and evaluation of biological activity of some Subsistuded 1,2,4-triazoles and their complexes with Co(II), Ni(II) and Zn(II) ions

2025-03-21T07:36:06+00:00

The present work describes the synthesis and characterization of new Schiff base of (E)-6-(4-(5-mercapto-4-((1-(4-methoxyphenyl)ethylidene)amino)-4H-1,2,4-triazol-3-yl)phenyl)-5H-pyrrolo[3,4-b]pyridine-5, 7(6H)-dione(L₂) by condensation reaction of 6-(4-(4-amino-5-mercapto-4H-1,2,4-triazol-3-yl)phenyl)-5H-pyrrolo[3,4-b]pyridine-5,7(6H)-dione (5)(L₁) with p- methoxy benzaldehyde. Using a 1:2 (metal : ligand) ratio, the ligands L₁and L₂ were utilized to create a novel complex containing cobalt(II), nickel(II), and zinc(II) metal ions . Fourier transform infrared (FT-IR), ultraviolet-visible (UV-Visible), nuclear magnetic resonance (¹H-NMR, ¹³C-NMR), micro elemental analysis (CHNS), thermal analysis, atomic absorption, molar conductance , and magnetic moment measurements have been used to examine and confirm new ligands (L₁, L₂) and their complexes. The observed data indicated the octahedral geometry around the Co(II), Ni(II )and Zn(II) complexes. Furthermore, the biological activity of ligands and its metal complexes in DMSO as control have also studied against four types of bacteria. The obtained results from inhibition zone values investigated that most metal complexes exhibited greater inhibition against all kinds of bacteria zone.

KEY WORDS: Triazole ligand, Transition metals, Benzohydrazide, 1,2,4-triazole complexes, Microbial activity

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1119-1136.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.8

Synthesis and characterization of complexes formed by Fe(III), Cr(III), Co(II), Cu(II), Cd(II), and Ag(I) ions with the drug captopril and the amino acid glycine

2025-03-21T07:38:58+00:00

The capability of Fe(III), Cr(III), Co(II), Cu(II), Cd(II), and Ag(I) ions to form stable mixed-ligand complexes was examined. The ligands are the antihypertensive drug captopril (L₁) and the glycine amino acid (L₂). The characterization data suggest that Fe(III), Cr(III), Co(II), Cu(II), and Cd(II) ions react with the L₁ and L₂ ligands in a ratio of 1:1:1 (metal ion: L₁:L₂), whereas the Ag(I) ions interacted with the ligands in a 2:1:1 ratio (metal ion: L₁: L₂). Results suggest that the L₁ ligand capture the metal ions using the S atom of the mercpto (SH) group and the O atom of the amide (C=O) group, whereas the L₂ ligand captures the metal ions using the O and N atoms of the carboxylate and amino groups, respectively. The XRD analysis demonstrated that Fe(III), Cr(III), Co(II) and Cu(II) complexes had well-defined and well-crystallized morphology, whereas the Cd(II) and Ag(I) complexes mainly possessed an amorphous structure. The microscopic characterizations indicate that the particles of Fe(III), Cr(III), Co(II), and Cu(II) complexes had rod-like shaped morphology with well-defined and clear shapes. The morphology of Cd(II) and Ag(I) complexes did not form short or long rods but rather contained particles in small aggregated shapes.

KEY WORDS: Drug captopril, Mixed-ligand complex, Glycine, Metal ion, Thermal decomposition

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1137-1152.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.9

Cytotoxicity of compounds isolated from Euphorbia abyssinica: A combined experimental and docking studies

2025-03-21T07:42:17+00:00

Euphorbia abyssinica Gmel. has been traditionally used in Ethiopia to treat various diseases, including swelling and cancer. This study assessed the cytotoxic effects of the ethanolic crude extract and its isolates from the aerial parts of E. abyssinica using the MTT assay method and molecular docking studies with the AutoDock Vina 4.2 program. E. abyssinica showed strong cytotoxicity against HeLa cells (IC₅₀ = 18.6 ± 0.7 μg/mL) and weak cytotoxicity against PC3 cells, with percent inhibition of 55.2% and 23.7% at 30.0 μg/mL, respectively. Among the fractions, the Dichloromethane fraction exhibited strong cytotoxicity against PC3 cells (IC₅₀ = 21.7 ± 0.9 μg/mL) and weak cytotoxicity against Hela cells, with 78.4% and 29.98% growth inhibition at 30.0 μg/mL, respectively. Dichloromethane fraction yielded β-sitosterol (1), friedelin (2) epifriedelanol (3), taraxerol (4) and glutinol (5). Friedelin (2) demonstrated strong cytotoxic activity against HeLa and PC3 cells. Similarly, epifriedelanol (3) showed strong cytotoxicity against PC3 cells (IC₅₀=28.4 ± 0.7 µM) and notable growth inhibition of HeLa cells (38.5% at 30 µM). Friedelin (2) showed better binding affinity and inhibition constant towards Human prostate specific antigen (PDB: 2ZCH) (-9.01 kcal/mol and 0.25 µM) and Alpha-actinin-4 (PDB: 6O31) (-7.61kcal/mol and 2.64 µM).

KEY WORDS: Euphorbia abyssinica Gmel., HeLa cells, PC3 cells, Cytotoxicity, MTT assay, Molecular docking

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1153-1166.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.10

Lipoxygenase inhibitory activity of phytoconstituents isolated from the rhizomes of Boesenbergia albosanguinea (Ridl.) Loes.

2025-03-21T07:46:19+00:00

This study aimed to investigate the compounds isolated from the rhizome extract of Boesenbergia albosanguinea. The extraction was performed using Soxhlet extraction of the dried powdered rhizome, following a polarity gradient of n-hexane, dichloromethane, and methanol. The phytochemicals were purified using chromatography techniques, and their structures were confirmed through spectroscopic analyses (IR, NMR, and MS) and comparison with existing literature. Additionally, the isolated compounds were evaluated for their lipoxygenase inhibitory activity. The isolation process successfully yielded eight phytochemicals belonging to various classes, including phenylpropanoid, chalcones, kavalactone, flavanones, flavonol, and flavone. These compounds were identified as elemicin (1), panduratin A (2), isopanduratin A (3), 5,6-dehydrokawain (4), pinostrobin (5), pinocembrin (6), kaempferol (7), and luteolin (8). Among these, luteolin (8) and kaempferol (7) demonstrated the most potent lipoxygenase inhibitory activity, with percentage inhibitions of 88.5% and 86.2%, respectively. These findings highlight the potential of B. albosanguinea as a natural source of lipoxygenase inhibitors, particularly in comparison to previously studied plant-based inhibitors. The strong inhibitory effects of luteolin (8) and kaempferol (7) underscore their relevance in the development of anti-inflammatory and nutraceutical formulations. This study contributes to the growing body of research on Boesenbergia species, offering a foundation for further pharmacological and industrial applications.

KEY WORDS: Zingiberaceae, Boesenbergia albosanguinea, Constituent, Flavonoid, Lipoxygenase

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1167-1176.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.11

Evaluation of cytotoxicity and radical scavenging activities of flavones isolated from the twigs of Dodonaea angustifolia

2025-03-21T07:50:40+00:00

Dodonaea angustifolia (commonly known as Kitikita in Amharic) is a medicinal plant widely used in traditional medicine for its diverse therapeutic properties. The twigs of the plant were extracted with 1:1 (methanol:dichloromethane mixture) and subjected to chromatographic techniques and yielded 8 pure compounds included: 5,7-dihydro-3,4′,6-trimethoxyflavone 1, 5,6,7-trihydroxy-3,4'-dimethoxyflavone 2, 5,7,4'-trihydroxy-3,6-dimethoxyflavone 3, 5-hydroxy-3,4",6,7-tetramethoxyflavone 4, 5,4'-dihydroxy-3,6,7-trimethoxyflavone 5, 5,7,8,4’-tetra hydroxy-3,6-dimethoxy flavone 6, l-C-syringylglycerol 7, and fraxetin 8. Their structural elucidation was performed using spectroscopic data (1D and 2D NMR) in combination with the literature values. The antibacterial, cytotoxic, and antioxidant activities of these isolated pure compounds were evaluated. Antibacterial assays, conducted against both Gram-positive and Gram-negative bacteria, revealed that the compounds exhibited no activity compared to standard antibiotics. In cytotoxicity tests using the KB-3-1 human cervix carcinoma cell line, the compounds 1, 3 and 5 showed moderate activity, with lower cytotoxicity relative to Cryptophycin 52. The antioxidant capacity, assessed using the DPPH radical scavenging assay, and compounds 1 and 3 indicated weak free radical scavenging potential. These findings highlight the chemical diversity of Dodonaea angustifolia twigs and their potential as sources of bioactive compounds for medicinal applications.

KEY WORDS: Dodonaea angustifolia, Structural elucidation, Cytotoxicity test, Antibacterial activity, Antioxidant activity

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1177-1184.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.12

Aqueous medium synthesis, characterization and evaluation of the antioxidant and antibacterial activities of new pyrimidine-and purine-ligated pyrrole

2025-03-21T07:53:40+00:00

A new pyrimidine- and purine-ligated pyrrole were synthesized through the Hantzsch multicomponent reaction using nucleobases (cytosine, adenine or guanine) as amine nucleophiles in water as solvent. The structures of the synthesized compounds were elucidated through proton (¹H) and carbon (¹³C) nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR) spectroscopy, mass spectrometry, and elemental analysis. The total antioxidant capacity (TAC) of the products was evaluated by the phosphomolybdenum assay. The in vitro antioxidant activity of the target compounds was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH^•) and 2,2′-azino-bis(3-ethylenzothiazoline-sulfonic acid) diammonium salt (ABTS^+•) free radicals. Compound 2c displayed the highest antioxidant activity against DPPH with IC₅₀ of 6.55 μg/mL, and 3c exhibited the highest antioxidant activity against ABTS with IC₅₀ of 18.37 μg/mL. Furthermore, the in vitro antibacterial properties of these compounds was assessed against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumonia ATCC 13883 (Gram-negative: G^-), and Staphylococcus aureus ATCC 25932 (Gram-positive: G⁺) bacterium, and compared with Gentamicin used as reference antibiotic. Compound 2a exhibited good antibacterial activity against Klebsiella pneumonia with inhibition zone of 17 mm. Compound 3a also showed a good antibacterial effect against E. coli taxon with inhibition zone of 18.5 mm relative to Gentamicin (20 mm).

KEY WORDS: Antibacterial activity, Antioxidant activity, Hantzsch synthesis, Nitrogenous bases, Pyrrole

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1185-1200.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.13

The synthesis of biologically active pyrazolo[3,4-b]pyridine and pyrido[2,3-d]pyrimidine derivatives

2025-03-21T07:59:31+00:00

. In this study, firstly, benzylidene derivatives were obtained by Knoevenagel condensation using various aryl aldehydes and malononitrile in the presence of ethanol and then these differently substituted benzylidene compounds were substituted with 5-amino-3-methyl-1-phenylpyrazole and 6-amino-1-amino-1-phenylpyrazole, respectively, 3-dimethyluracil and ytterbium(III) trifluoromethane-sulfonate [Yb(OTf)₃] or acetic acid catalyzed pyrazolo[3,4-b]pyridine and pyrido[2,3-d]pyrimidine derivatives were synthesized (5a-5i), and the structures of these compounds, which were purified by different methods, were elucidated by spectroscopic methods such as FTIR, ¹H-NMR, ¹³C-NMR and GS-MS. In our study, compounds 3a, 5a and 5c were synthesized for the first time. In addition, Yb(OTf)₃, one of the metal catalysts considered environmentally friendly catalysts, was used in this research. The genotoxic and antigenotoxic properties of the synthesized compounds were investigated in vitro using Ames Salmonella/microsome mutagenicity assay in the concentration range of 0.2-1.0 mM/plate. The results revealed that none of the compounds were mutagenic on three different Salmonella typhimurium strains up to the highest tested concentration. Moreover, in our study, 5a, 5e, 5f and 5h showed significant antigenotoxic effects ranging from moderate to strong against mutagen-induced DNA damage at relatively higher doses.

KEY WORDS: Prido[2,3-d]pyrimidine, Pyrazolo[3,4-b]pyridine, Heterocyclic compounds, Benzylidene derivatives

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1201-1212.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.14

Kinetics, isotherms and thermodynamics study of eosin yellow dye adsorption from aqueous solutions by MnO2@rGO nanocomposite

2025-03-21T08:01:32+00:00

This study explores the use of MnO₂@rGO nanocomposite as an adsorbent for Eosin Y dye. It was found that equilibrium for Eosin Y adsorption on the MnO₂@rGO nanocomposite surface is achieved in 120 min. The nanocomposite demonstrated a high dye adsorption rate due to its extensive surface area, which facilitates substantial dye uptake‏. To assess the adsorption kinetics of Eosin Y on the MnO₂@rGO surface; the data suggested that the pseudo-second-order model fit the data better. The Langmuir, Freundlich, and Temkin equations are examples of linear forms of adsorption isotherms that were investigated in this study and ‎the substantial correlation coefficient for the Freundlich isotherm model suggests that the ‎adsorption of Eosin Y dye on the MnO₂@rGO nanocomposite surface is multilayered. Furthermore, the effects of pH, ionic strength, and thermodynamic factors on maximum adsorption were examined. In addition, thermodynamic functions including entropy (∆S), enthalpy (∆H), and Gibbs free energy (∆G) were evaluated and the adsorption is physical.

KEY WORDS: MnO₂@rGO nanocomposite, Eosin yellow dye, Adsorption, Adsorption isothermal, Characterization, Thermodynamics, Kinetics

Bull. Chem. Soc. Ethiop. 2025, 39(6), 1213-1226.

DOI: https://dx.doi.org/10.4314/bcse.v39i6.15