Synthesis, Structural Characterization, and Biological Activities of Organically Templated Cobalt Phosphite (H2DAB)[Co(H2PO3)4]·2H2O

A novel hybrid cobalt phosphite, (H2DAB)[Co(H2PO3 )4 ] 2H2O, was synthesized by using a slow evaporation method in the presence of cobalt nitrate, phosphorous acid, and 1,4-diaminobutane (DAB = 1,4-diaminobutane) as a structure-directing agent. Single-crystal X-ray diffraction analysis showed that the compound crystallizes in the triclinic system (space group P-1(n.2)) with the following unit cell parameters (Å, ◦ ) a = 5.4814 (3), b = 7.5515 (4), c = 10.8548 (6), α = 88.001 (4), β = 88.707 (5), γ = 85.126 (5), and V = 447.33 (4) Å3 . The crystal structure is built up from corner-sharing [CoO6 ] octahedra, forming chains parallel to [001], which are interconnected by H2PO3 − pseudo-tetrahedral units. The diprotonated cations, residing between the parallel chains, interact with the inorganic moiety via hydrogen bonds, thus leading to the formation of the 3D crystal structure. The Fourier transform infrared spectrum showed characteristic bands corresponding to the phosphite group and the organic amine. The thermal behavior of the compound mainly consisted of the loss of its organic moiety and the water molecules. The biological tests exhibited significant activity against Candida albicans and Escherichia coli strains at different concentrations, while less inhibitory activity was pronounced against Staphylococcus epidermidis and Saccharomyces cerevisiae, and in the case of multi-cellular organisms, no activity against the nematode model Steinernema feltiae was detected

Synthesis, Structural Characterization, and Biological Activities of Organically Templated Cobalt Phosphite (C4N2H14)Co(H2PO3)4·2H2O

A novel hybrid phosphite [(C4N2H14)Co(H2PO3)4·2H2O] was synthesized with 1,4- diaminobutane (dabn) as a structure-directing agent using slow evaporation method. Single crystal X-ray diffraction analysis showed that it crystallizes in the triclinic system (S.G: P-1, #2) with the following unit cell parameters (Å, °) a = 5.4814 (3), b = 7.5515 (4), c = 10.8548 (6), α = 88.001 (4), β = 88.707 (5), γ = 85.126 (5). The crystal structure was built up from corner-sharing [CoO6]-octahedrons, forming chains parallel to [001], which are interconnected by H2PO3 pseudo-pyramid units. The diprotonated 1,4-diaminobutane molecules, residing between the parallel chains, interacted with the inorganic moiety via hydrogen bonds leading thus to the formation of the 3D crystal structure. The Fourier transform infrared result exhibited characteristic bands corresponding to the phosphite group and the organic molecule. The thermal decomposition of the compound consists mainly of the loss of the organic moiety and the water molecules. The biological tests exhibited significant activity against Candida albicans and Escherichia coli strains in all used concentrations, while less activity was pronounced when tested against Staphylococcus epidermidis and Saccharomyces cerevisiae, while there was no activity against the nematode model Steinernema feltiae

Electrical Properties of a CeO 2

The electrical conduction of a series of polycristalline [(1−x)CeO2⋅x/2Bi2O3] samples has been analyzed using electrical impedance spectroscopy, in the temperature range 25 to 750∘C. Samples have been prepared via a coprecipitation route followed by a pyrolysis process at 600∘C. For compositions x≤0.20, Ce1−xBixO2−x/2 solid solutions, with fluorite cubic structure, are obtained. In the composition range 0.30≤x≤1, the system is biphasic with coexistence of cubic and tetragonal structures. To interpret the Nyquist representations of electrical analyses, various impedance models including constant phase elements and Warburg impedances have been used. In the biphasic range (0.30≤x≤0.7), the conductivity variation might be related to the increasing fraction of two tetragonal β′ and β-Bi2O3 phases. The stabilization of the tetragonal phase coexisting with substituted ceria close to composition x=0.7 is associated with a high conduction of the mix system CeO2-Bi2O3

Analyse expérimentale des caractéristiques thermiques de la biomasse "coque de noix d'arganier" en tant que ressource énergétique

International audienceArgan nut shell (ANS) is one of the most abundant agricultural by-product in the southwestern of Morocco. This study aims to focus on thermal characteristics of ANS biomass for alternative energy production. Physicochemical studies were done to characterize biomass-based material. Moreover, thermal degradation characteristics and kinetic parameters were assessed under pyrolysis and oxidizing conditions by means of thermogravimetric methods. Fundamental tests involving particle combustion of ANS and coal were carried out, and a comparison was performed. The results exhibit a negligible amount of nitrogen and sulfur and a heating value of 20.63 MJ kg-1 compared to 24 MJ kg-1 for high grad coals. Furthermore, ANS follows the usual structural decomposition of lignocellulosique biomass, while coal reveal a discrete devolatilization zone. In addition, combustion tests show a significant burning period and high particle temperature. This experimental research is intended to provide a reference data of ANS biomass for energy recovery through combustion

Experimental Analysis on Thermal Characteristics of Argan Nut Shell (ANS) Biomass as a Green Energy Resource

International audienceArgan nut shell (ANS) is one of the most abundant agricultural by-product in the southwestern of Morocco. This study aims to focus on thermal characteristics of ANS biomass for alternative energy production. Physicochemical studies were done to characterize biomass-based material. Moreover, thermal degradation characteristics and kinetic parameters were assessed under pyrolysis and oxidizing conditions by means of thermogravimetric methods. Fundamental tests involving particle combustion of ANS and coal were carried out, and a comparison was performed. The results exhibit a negligible amount of nitrogen and sulfur and a heating value of 20.63 MJ kg-1 compared to 24 MJ kg-1 for high grad coals. Furthermore, ANS follows the usual structural decomposition of lignocellulosique biomass, while coal reveal a discrete devolatilization zone. In addition, combustion tests show a significant burning period and high particle temperature. This experimental research is intended to provide a reference data of ANS biomass for energy recovery through combustion

Well-designed WO₃/Activated carbon composite for Rhodamine B Removal: Synthesis, characterization, and modeling using response surface methodology

<p>This study focuses on the preparation of WO₃ oxide nanoparticle/Activated carbon composite (WO₃/AC) for Rhodamine B (RhB) adsorption. The prepared samples were characterized using X-Ray Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller surface area (BET), Raman Spectroscopy and Thermogravimetric analyses (ATG-ATD). Adsorption experiments of RhB onto WO₃/AC were carried out in a batch reactor and different operational parameters were investigated. The RhB adsorption process was well fitted by pseudo-second-order kinetic and Langmuir isotherm models (1666.67mg.g⁻¹). Moreover, the values of thermodynamic parameters indicate the spontaneous, endothermic and physisorption adsorption nature. Finally, adsorption mechanism was proposed on the basis Raman analyses before and after adsorption.</p

Adsorption kinetics and surface modeling of aqueous methylene blue onto activated carbonaceous wood sawdust

<p>In this work, Sawdust was used to develop a new low-cost adsorbent and study its application to remove methylene blue dye from aqueous solution. Sawdust was calcined under air atmosphere at three different temperatures (300°C, 400°C, and 500°C) using phosphoric acid (H₃PO₄) as an activating agent. The structure, morphology, surface functions and the chemical composition of adsorbent were characterized by Fourier Transform Infrared spectra (FTIR), X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), specific surface area (BET) and Boehm method. Different operational parameters such as pH, adsorbent loading, contact time and were investigated to evaluate experimental data. The adsorption of MB on SD-300, SD-400, and SD-500 show that the pseudo-second-order and Langmuir models fitted better the experimental results of MB adsorption onto all adsorbents. The maximum capacities based on the Langmuir model were 416.7 mg.g⁻¹ for SD-300, 526.3 mg.g⁻¹ for SD-400, and 819.7 mg.g⁻¹ for SD-500. The positive values of ΔG, ΔH, and ΔS implied that the adsorption process was non-spontaneous and endothermic nature. Finally, Regeneration of the SD-500 was investigated and optimization was performed using CCD combined with RSM.</p

Synthesis and characterization of mesoporous geopolymer based on Moroccan kaolinite rich clay

International audienc