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Preparation and Characterization of Activated Carbons from Palm Nut Shells: Effects of Calcination Temperature on Porosity and Chemical Properties

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Open Journal of Inorganic Chemistry 2024年第2期14卷 19-32页

作者： charly Mve Mfoumou Berthy Lionel Mbouiti Spenseur Bouassa Mougnala Pradel Tonda-Mikiela guy Raymond Feuya Tchouya Laboratoire de Chimie des Milieux et des Matriaux Inorganiques (LC2MI) URCHI Universit des Sciences et Techniques de Masuku (USTM) Franceville Gabon Dpartement de Chimie Facult des Sciences Universit des Sciences et Techniques de Masuku (USTM) Franceville Gabon Ecole Doctorale des Sciences Fondamentales et appliques (ED-SFA) Laboratoire de Chimie des Milieux et des Matriaux Inorganiques (LC2MI) URCHI USTM Franceville Gabon

Activated carbons (ACs) calcined at 400˚C, 500˚C, and 600˚C (AC-400, AC-500, and AC-600) were prepared using palm nut shells from gabon as raw material and zinc chloride (ZnCl2) as a chemical activating agent. Prepared ACs were characterized by physisorption of nitrogen (N2), determination of diode and methylene blue numbers for studies of porosity and by quantification and determination of surface functional groups and pH at point of zero charge (pHpzc) respectively, for studies of chemical properties of prepared ACs. Then, effects of calcination temperature (Tcal) on porosity and chemical properties of prepared ACs were studied. The results obtained showed that when the calcination temperature increases from 500˚C to 600˚C, the porosity and chemical properties of prepared ACs are modified. Indeed, the methylene blue and iodine numbers determined for activated carbons AC-400 (460 and 7.94 mg·g−1, respectively) and AC-500 (680 and 8.90 mg·g−1, respectively) are higher than those obtained for AC-600 (360 and 5.75 mg·g−1, respectively). Compared to the AC-500 adsorbent, specific surface areas (SBET) and microporous volume losses for AC-600 were estimated to 44.7% and 45.8%, respectively. Moreover, in our experimental conditions, the effect of Tcal on the quantities of acidic and basic functional groups on the surface of the ACs appears negligible. In addition, results of the pHpzc of prepared ACs showed that as Tcal increases, the pH of the adsorbents increases and tends towards neutrality. Indeed, a stronger acidity was determined on AC-400 (pHpzc = 5.60) compared to those on AC-500 and AC-600 (pHpzc = 6.85 and 6.70, respectively). Also according to the results of porosity and chemical characterizations, adsorption being a surface phenomenon, 500˚C appears to be the optimal calcination temperature for the preparation of activated carbons from palm nut shells in our experimental conditions.

关键词： Palm Nut Shells Activated Carbon Calcination Temperature Porosity and Chemical Properties

Fixed-Bed Column Adsorption Modeling of MnO₄- Ions from Acidic Aqueous Solutions on Activated Carbons Prepared with the Biomass

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Open Journal of Inorganic Chemistry 2023年第2期13卷 25-42页

作者： charly Mve Mfoumou Francis Ngoye Pradel Tonda-Mikiela Mbouiti Lionel Berthy Bouassa Mougnala Spenseur guy Raymond Feuya Tchouya Laboratoire de Chimie des Milieux et des Matériaux Inorganiques (LC2MI) URCHI Université des Sciences et Techniques de Masuku (USTM) Franceville Gabon Département de Chimie Faculté des Sciences Université des Sciences et Techniques de Masuku (USTM) Franceville Gabon

Activated carbons calcined at 400˚C and 600˚C (AC-400 and AC-600), prepared using palm nuts, collected in the town of Franceville in gabon, were used to study the dynamic adsorption of MnO4- ions in acidic media on fixed bed column and on the kinetic modeling of experimental data of breakthrough curves of MnO4- ions obtained. Results on the adsorption of MnO4- ions in fixed-bed dynamics obtained on AC-400 and AC-600 adsorbents beds indicated that the AC-400 bed appears to be the most efficient in removing MnO4- ions in acidic media. Indeed, the adsorbed amounts, the adsorbed capacities at saturation and the elimination percentage of MnO4- ions obtained with AC-400 (31.24 mg;52.06 mg·g-1 and 41.65% respectively) were higher compared to those obtained with AC-600 (9.87 mg;16.45 mg·g-1 and 17.79% respectively). The breakthrough curves kinetic modeling revealed that the Thomas model and the pseudo-first-order kinetic model were the most suitable models to describe the adsorption of MnO4- ions on adsorbents studied in our experimental conditions. The results of the intraparticle diffusion model showed that intraparticle diffusion was involved in the adsorption mechanism of MnO4- ions on investigated adsorbents and was not the limiting step and the only process controlling MnO4- ions adsorption. In contrast to AC-400, the intraparticle diffusion on AC-600 bed plays an important role in the adsorption mechanism of MnO4- ions.

关键词： Acidic Media MnO4- Biomass Activated Carbon Dynamic Adsorption Kinetics Models

Elimination, Kinetics and Thermodynamics of Fe(II) Ions by Adsorption in Static and Dynamic Conditions on Activated Carbons in Aqueous Media

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Journal of geoscience and Environment Protection 2024年第10期12卷 181-203页

作者： Spenseur Bouassa Mougnala charly Mve Mfoumou Berthy Lionel Mbouiti Pradel Tonda-Mikiela Francis Ngoye Ferdinand Evoung Evoung Jean Aubin Ondo guy Raymond Feuya Tchouya Laboratoire de Chimie des Milieux et des Matriaux Inorganiques (LC2MI) Dpartement de Chimie Universit des Sciences et Techniques de Masuku (USTM) Franceville Gabon Ecole Doctorale des Sciences Fondamentales et Appliques (ED-SFA) LC2MI USTM Franceville Gabon Dpartement de Chimie Facult des Sciences (FS) USTM Franceville Gabon Laboratoire Pluridisciplinaire des Sciences (LAPLUS) Ecole Normale Suprieure (ENS) Libreville Gabon

This work investigated the removal, kinetics and thermodynamics of iron(II) ions (Fe(II)) by adsorption in static and dynamic conditions in aqueous media on activated carbons (AC-i30min, AC-i1h, and AC-i24h), prepared from palm nut shells collected in the city of Franceville to gabon, using potassium hydroxide (KOH) as the activating agent. Results on the elimination of Fe(II) in static and dynamic adsorption on prepared activated carbons (ACs) showed that the AC-i24h adsorbent has the best Fe(II) adsorption capacities at saturation (Qsat). The Qsat obtained on AC-i24h in static and dynamic conditions (17.87 and 10.38 mg/g, respectively) were higher than those of AC-i30min (13.89 and 5.54 mg/g respectively) and AC-i1h (14.92 and 8.64 mg/g respectively). Moreover, the static adsorption was more effective in the removal of Fe(II) ions in aqueous media in our experimental conditions. The percentage removal (%E) of Fe(II) obtained on prepared activated carbons in static conditions was better than those obtained in dynamic conditions, especially on AC-i24h, where the %E was 89.27% in static and 61.56% in dynamic. In kinetics, results showed that the pseudo-second-order kinetic model best described the adsorption mechanisms of Fe(II) on prepared activated carbons in static adsorption, with mainly of chemisorption on the solid surfaces. However, in dynamic conditions, the pseudo-first-order kinetic model was more suitable. In addition to the weak interactions between Fe(II) and the activated carbon surfaces, strong interactions (chemisorption) were also observed. Also, thermodynamic data obtained on AC-i24h in static adsorption indicated that the adsorption of Fe(II) was spontaneous and increased with temperature (Δg˚ H˚ = 503.54 KJ/mol).

关键词： Palm Nut Shells Activated Carbon Removal Fe(II) Static and Dynamic Adsorption Kinetics Thermodynamics

Synthesis, Structural Characterization and Antimicrobial Activity of a Novel Cobalt(II) Complex Based on 3-Methyl-1-Phenyl-4-(2-Thienoyl)-Pyrazol-5-One

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Journal of Modern Physics 2023年第8期14卷 109-126页

作者： Emeline Sorelle Mefouegang Claudelle Sybilline Anensong Djadock golngar Djimassingar gabriel Tchuente Kamsu Donald Raoul Tchuifon Tchuifon Alain charly Tagne Kuate Dirk Bockfeld Jean Ngoune Research Unit of Noxious Chemistry and Environmental Engineering Department of Chemistry Faculty of Science University of Dschang Dschang Cameroon Department of Fundamental Sciences Mongo Polytechnique University Institute (IUPM) Mongo Chad Research Unit of Microbiology and Antimicrobial Substances Department of Biochemistry Faculty of Science University of Dschang Dschang Cameroon Department of Process Engineering Laboratory of Energy Materials Modeling and Method National Higher Polytechnic School of Douala University of Douala Douala Cameroon Institute of Inorganic and Analytical Chemistry Technical University of Braunschweig Braunschweig Germany

New cobalt(II) complex, [Co(O2C15H11N2S)2(OH2)2]∙2H2O (1∙2H2O), has been synthesized upon reaction of cobalt chloride hexahydrate (Co(Cl)2∙6H2O) with 3-methyl-1-Phenyl-4-(2-thienoyl)-pyrazol-5-one (referred as HL) in ethanol at room temperature. Single crystal X-ray diffraction (XRD), spectroscopic methods, and microelemental analyses were used to characterize 1∙2H2O. Compound 1∙2H2O crystallizes in the orthorhombic crystal system with a Pbca space group and with the cobalt atom being pseudo-octahedral coordinated. The broth microdilution technique was used to screen the free ligand (HL) and the complex (1∙2H2O) for antimicrobial activities. HL has a low activity (MIC > 100 μg/mL) on all microorganisms, whereas compound 1∙2H2O displayed moderate activity (10 ∙2H2O exhibited bactericidal and fungicidal activity respectively on all the bacteria and yeasts tested. These findings reveal that the antimicrobial activity of HL was enhanced upon coordination to Co(II) ion against all microorganisms (bacteria and fungus).

关键词： Cobalt Acylpyrazolone X-Ray Diffraction Antimicrobial Activity 3-Methyl-1-Phenyl-4-(2-Thienoyl)-Pyrazol-5-One

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