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Item Synthesis and characterization of MoO3: application to the photo production of oxygen under visible light(Springer, 2024) Koriche, Nesrine; Abbas, Moussa; Trari, MohamedOne of the most striking features of molybdenum oxide is the versatility of its catalytic properties, which are determined by the valence states of molybdenum and its coordination. It may be anticipated that MoO3 surface must contain catalytic sites which are active in different types of elementary steps. MoO3 was successfully synthesized by hydrothermal route at 400 °C, acquiring n-type conduction, due to oxygen deficiency. The single phase, elucidated by X-ray diffraction, crystallizes in an orthorhombic unit cell (Space Group (SG) Pbnm, N° 62) with a crystallite size of 12 nm. MoO3 is a direct band gap semiconductor with a forbidden band value of 2.93 eV where the electrical conduction occurs by low polaron hopping between mixed valences Mo+6/+5 with an activation energy of 0.14 eV. The thermo-power indicates n-type conduction, and confirmed by the capacitance-potential measurement; the latter gives an electrons density of 1.87 × 1020/cm3and a mobility of 1.77 × 10−6 m2/V.s. The flat band potential Vfb (0.11 VSCE) is determined from the capacitance measurement. The physical and chemical characterizations are correlated for the construction of the potential diagram in order to assess the photo electrochemical properties of MoO3 for the oxygen evolution. The valence band, is located above the O2/H2O potential ( ~ 1.3 VSCE), allowing O2 evolution upon visible light and the oxide is photocathodically protected against corrosion. An evolution rate of 0.13 mL/(mg. h) is obtained within 20 min. at optimal conditions (100 mg of catalyst and 50 °C).Item Adsorption Behavior of Methylene Blue Onto Activated Coconut Shells: Kinetic, Thermodynamic, Mechanism and Regeneration of the Adsorbent(SAGE, 2024) Abbas, Moussa; Trari, MohamedAdsorption techniques are widely used to remove some classes of pollutants from waters, especially those which are not easily biodegradable. The removal of Methylene blue (MB), as a pollutant, from waste waters of textile, paper, printing and other industries has been addressed by the researchers. The aim of this study is to eliminate MB by Activated Coconut Shells (ACS) produced at low cost by adsorption in batch mode. The ACS was characterized by the FTIR spectroscopy and point of zero charge (pHpzc: 5.06). Some examined factors were found to have significant impacts on the MB uptake of ACS like the initial dye concentration Co (40-120 mg/L), solution pH (2-8), ACS dose (1-12 g/L), agitation speed (50-500 r/min), particles size (1.0- 1.2 mm) and temperature (298-333 K). The best capacity was found at pH 6 with an adsorbent dose 8 g/L, an agitation speed 200 r/min and a contact time of 60 min. Modeling Kinetics and Isotherms shows that the pseudo-second-order kinetic model with R2 (0.935 -0.998) and Langmuir adsorption isotherm model provide better fitness to the experimental data with the maximum adsorption capacity of 30.30 mg/g at 25°C. The separation factor R L (0.933-0.541) in the concentration range studied (10-120 mg/L) shows a favorable adsorption. The isotherms at different temperatures have been used for the determination of the free energy ΔG ° (198-9.72 kJ/mol); enthalpy ΔH ° (82.082 kJ/mol) and entropy ΔS o (245.689 J/K mol) to predict the nature of MB adsorption process. The positive values of (ΔG o ) and (ΔHo ) indicate a non-spontaneous and endothermic MB adsorption with a chemisorption. The adsorbent elaborated from Coconut Shells was found to efficient and suitable for the removal of MB dye from aqueous solutions, due to its availability, low cost preparation and good uptake capacity.Item Electrochemical Study of CuFe2O4 Synthetized by Sol–Gel and Electro-photo-oxidation of Rhodamine B Under Sunlight(Springer, 2024) Touati, H.; Sahmi, A.; Trari, MohamedThe spinel CuFe2O4 elaborated by sol–gel route crystallizes in a tetragonal structure with a crystallite size of 444 ± 2 nm and a zeta potential of − 35 mV. The diffuse reflectance spectroscopy and photo-electrochemistry were undertaken for its characterization. The direct gap (1.55 eV) ideal for the solar energy conversion is assigned to the transition :Feoc3+:t2g→Feoc4+: eg in agreement with the red color, allowing more than half of the solar spectrum to be converted into chemical energy. The narrow valence band deriving from Fe3+: t2g orbital induces a low electron mobility (µ = 8.91 × 10−13 cm2 V−1 s−1). The cyclic voltammetry in Na2SO4 (10−2 M) exhibits low hysteresis that resembles a chemical diode. The electrical conductivity of CuFe2O4 is a characteristic of a non-degenerate semiconductor with activation energy (Ea) of 0.20 eV where the electron transfer occurs by low lattice polaron hopping between mixed valences Fe4+/Fe3+ octahedrally coordinated. The semi-logarithmic plot (logJ–E) indicates a chemical stability of CuFe2O4, while the photo-chronoamperometry corroborates the p-type behavior, a result confirmed by the capacitance measurement where an electron density (NA) of 0.176 × 1023 cm−3 and a flat band potential (Efb) equal to − 0.56 VSCE were extracted. As application and on the basis of the potential diagram, Rhodamine B (Rh B, 20 mg L−1), a cationic dye, is electrostatically attracted by the electrode surface and successfully oxidized by electrocatalysis on CuFe2O4. The kinetics of oxidation of Rh B followed by chemical oxygen demand (COD) analysis, which gave an abatement of 56% under a current of 150 mA, an enhancement up to 70%, was reached by electro-photocatalysis under sunlight smaller than that analyzed by UV–visible spectrophotometry (88%). The color removal follows a pseudo-first-order model with a half-life t1/2 of 57 min; a reaction mechanism by O2•− and •OH radicals is suggested. Graphical Abstract: (Figure presented.)Item Removal of Amoxicillin From Wastewater Onto Activated Carbon: Optimization of Analytical Parameters by Response Surface Methodology(SAGE Publications Inc., 2024) Abbas, Moussa; Trari, MohamedAntibiotics are widely used in veterinary and human medicine, but these compounds, when released into the aquatic environment, present potential risks to living organisms. In the present study, the activated carbon (AC) used for their removals is characterized by FT-IR spectroscopy, BET analysis and Scanning Electron Microscopy (SEM) to determine the physicochemical characteristics. Response surface methodology (RSM) and Box-Behnken statistical design (BBD) were used to optimize important parameters including pH (2-12), temperature (20-45°C), and AC dose (0.05-0.20 g). The experimental data were analyzed by analysis of variance (ANOVA) and fitted to second-order polynomial using multiple regression analysis. The optimal conditions for maximum elimination of Amoxicillin (Amox) are (Dose: 0.124 g, pH 5.03 and 45°C) by applying the desirability function (df). A confirmation experiment was carried out to evaluate the accuracy of the optimization model and maximum removal efficiency (R = 89.999%) was obtained under the optimized conditions. Several error analysis equations were used to measure goodness of fit. Pareto analysis suggests the importance of the relative order of factors: pH > Temperature > AC dose in optimized situations. The equilibrium adsorption data of Amox on Activated Carbone were analyzed by Freundlich, Elovich, Temkin and Langmuir models. The latter gave the best correlation with qmax capacities of 142.85 mg/g (R2 = 0.999) at 25°C is removed from solution. The adsorption process is dominated by chemisorption and the kinetic model obeys a pseudo-second order model (R2 = 0.999).Item Electrochemical Deposition of Hematite α-Fe2O3 Thin Films for Photo-Current Generation Application(Pleiades Publishing, 2024) Mokhtari, S.; Bouhdjer, Lazhar; Dokhan, Nahed; Aoudjit, Lamine; Imma, H.; Omeiri, Said; Trari, MohamedIn the field of sustainable hydrogen production, hematite (α-Fe2O3) is a promising material owing to its optical band gap and water oxidation/reduction energies. In this context, the main objective of this work is devoted to the synthesis of α-Fe2O3 by electrochemical anodization of iron sheet using two anodization voltages (20 and 30 V), followed by annealing at 450°C (1.5 h) in air. Indeed, annealing is a necessary but not sufficient condition for the hematite prepared electrochemically. Furthermore, we discuss the effect of anodizing voltage and analyze its influence on the properties of the films namely structural, morphological, optical, electrochemical and photoelectrochemical (PEC) properties. The annealed Fe2O3 sample, anodized at 30 V, demonstrates a net photocurrent density of 0.81 mA/cm2 at 0.744 VRHE in KOH (1 M). The obtained results indicate that the α-hematite thin films synthesized by anodization technique under optimized conditions is a promising photoanode in PEC cells.Item Reduction of 4-Nitrophenol and Adsorption of Rhodamine B Using Reduced Graphene Oxide-Copper Sulfide Nanomaterial(Pleiades Publishing, 2024) Mokhtari, S.; Aoudjit, Lamine; Ben Hariz, S. Habi; Dokhan, Nahed; Trari, MohamedPolyethylene imine (PEI) is used as an effective chemical agent for the reduction of graphene oxide (GO) to reduced graphene oxide (rGO). It is water-soluble, stable and cost-effective, and the reaction condition is easily achievable. The rGO nanocomposite are decorated with CuS nanoparticles by a single-step hydrothermal method. GO is assisted by precursors of Cu2+ and S2– in well-defined ratios. Several analysis methods are used such as UV–Vis, FTIR, XRD with SEM coupled with EDS to develop the structure and morphology of synthesized rGO-CuS nanocomposites. GO is assisted by Cu2+ and S2– precursors in well-defined ratios. Several analysis methods are used such as UV–Vis spectrophotometry, FTIR spectroscopy, X‑ray diffraction (XRD) and scanning electron microscopy (SEM) for the structural and morphological characterizations of the synthesized rGO-CuS nanocomposites. The structural and optical properties are discussed and the results obtained are compared to the literature. The prepared material has been tested in various applications, it is used as a Calisher for the reduction of 4-nitrophenol to 4-aminophenol and the degradation of Rhodamine B (Rh B).Item Elaboration of a new Activated Carbon derived from the Crown of Oak (ACOW) to removal the toxic Iodine: Kinetic, Isotherms modelling and Thermodynamics Study(Taylor & Francis, 2024) Aksil, Tounsia; Abbas, Moussa; Trari, MohamedThe current study aims to develop a new adsorbent material using oak crown and explore its effectiveness in removing I2 ions through a series of batch experiments. ACOW was characterised by zero charge (pHpzc) and FTIR spectroscopy. The impact of the initial I2 concentration (20-100 mg/L), temperature (25-55 °C), pH (2-14), adsorbent dosage (2-10 g/L), Stirring speed (100-900 rpm), particle size (100-2000μm) and contact time (0-30 min) on I2 adsorption was examined. The adsorption kinetic obeys the pseudo-second order model with a determination coefficient (R2) equal to 0.999. Adsorption follows the Langmuir equation well, with the best fit to the experimental data at equilibrium. A qmax value (= 103.606 mg/g) at 25°C and 120.773 mg/g at 55°C were eliminated under the optimised conditions, indicating homogeneous adsorption on the surface of the adsorbent. The thermodynamic parameters gave a negative free energy ΔGo (-3.445 to -5.629 kJ/mol), a positive enthalpy ΔHo (18.406 kJ/mol) and an activation energy Ea (= 22.599 kJ/mol), thus confirming the spontaneous and endothermic nature of adsorption of iodine on ACOW. The positive entropy ΔSo (0.0733 kJ/mol K) show increased randomness of the solid-liquid interface during the adsorption.Item Electrochemical properties of CoFe2O4 prepared by sol–gel route. Sono-photocatalysis degradation of Rhodamine B by solar light(Springer Nature, 2024) Sahmi, Abdelaziz; Bensadok, Kenza; Trari, MohamedThe present work deals with removing Rhodamine B (Rh B) from aqueous solution by Photo Sono-assisted catalytic process on CoFe2O4 elaborated by sol–gel method. The spinel identified by X-ray diffraction presents a face-centered cubic lattice with a grain size of 360 (± 2 nm) and a zeta potential of − 33 mV. The oxide is characterized by diffuse reflectance and photo-electrochemistry. The direct gap (1.42 eV) is assigned to the internal transition: Feoc3+:t2g→Feoc4+:eg in agreement with the red color. The narrow valence band deriving from Fe3+: 3d parentage induces a low hole mobility (µh = 8.91 × 10−6 cm2 V−1 s−1). The electrical conductivity of CoFe2O4 is characteristic of semiconducting comportment with activation energy (Ea) of 0.57 eV, where the electron jump occurs by small lattice polaron between mixed valences Fe3+/Fe4+. The intensity potential J(E) profile in Na2SO4 (10–2 M) exhibits a small hysteresis loop. The chrono-amperometry shows p-type conductivity due to metal insertion, a result confirmed by the capacitance measurement where a hole density (NA) of 0.176 × 1023 cm−3 and a flat band potential (Efb) equal to − 0.8 V are determined. As an application, Rh B (20 mg L−1) is successfully oxidized by photocatalysis on CoFe2O4 with a reduction of 53% under solar light. An enhancement up to 88% has been reached by sono-photocatalysis at an ultrasonic wave (USW) frequency (60 kHz, 550 W) within 105 min.; the Rh B elimination follows a pseudo-first-order kinetic with a rate constant of 1.23 × 10–2 mn−1 (t1/2 = 56 min), and a reaction mechanism is suggested, was entirely discolored in the USW/solar light/CoFe2O4 system. The Sono-photocatalytic degradation of Rh B depends on the initial Rh B concentration, acoustic power, and catalyst dose. At low ultrasound frequency, the results indicated a total chemical oxygen demand (COD) when applying the system USW/solar light/CoFe2O4, signifying its great potentiality for the treatment of water.Item Efficient oxidation by sono-photo-electrocatalysis of rhodamine B using MgFe2O4 as photoanode(Springer Nature, 2024) Sahmi, Abdelaziz; Bensadok, Kenza; Trari, MohamedThe present work describes the colour removal of Rhodamine B (Rh B), a cationic dye by photo-electrocatalysis and sono-photo-electrocatalysis on MgFe2O4 as an anode. The spinel MgFe2O4 synthesized by sol–gel route was characterized by physical and electrochemical methods, a preamble of Rh B oxidation. The XRD pattern shows the formation of the single phase, which crystallizes in a face-centred cubic lattice (space group, Fd − 3 m), with spherical crystallites (0.42 nm). The Zeta-sizer analysis gives an average grain size of 0.46 µm and a zeta potential of − 30 mV. The SEM analysis revealed the porosity of the oxide and the Mg-O and Fe–O bonds were confirmed by the FT-IR analysis. The direct optical gap (2.16 eV) assigned to d − d internal transition comes from the crystal field splitting of Fe3+ octahedrally coordinated. The low electron mobility is assigned to a narrow conduction band of Fe3+—3d parentage with activation energy (0.12 eV) in conformity with a conduction mechanism by small lattice polaron hopping. The intensity potential J(E) profile in Na2SO4 (10−2 M) exhibits a small hysteresis similar to a chemical diode. The semi-logarithmic plot (logJ − E) indicates the chemical stability of MgFe2O4 in the working solution (Na2SO4). Curiously and unlike most spinels, the capacitance plot exhibits n-type conduction confirmed by chrono-amperometry, plotted at the free potential (+ 0.5 V) with a flat band potential (Efb) of 0.29 V, due to Fe3+ insertion. As an application, Rh B (20 mg L−1) was successfully oxidized by photo-electrocatalysis on MgFe2O4 with an abatement of 75% under solar irradiation and a direct current of 150 mA which has a bactericidal effect. An enhancement up to 97% has been reached by sono-photo-electrocatalysis at a frequency of 60 kHz; almost complete discoloration occurred within 90 min in the “US-Electric Current-Sunlight-MgFe2O4”. The Rh B elimination follows a pseudo-first-order kinetic with a rate constant of 3.9 × 10−2 mn−1 (t1/2 = 18 min), and a reaction mechanism is suggested.Item Hydrothermally synthesized reduced graphene Oxide-Copper sulfide nanomaterial for application as supercapacitor(Pleiades Publishing, 2023) Mokhtari, S.; Dokhan, Nahed; Aoudjit, Lamine; Trari, Mohamed; Omeiri, SaidThis work is dedicated to the synthesis of rGO-CuS (reduced graphene oxide-copper sulfide) nanocomposites through a low-cost and environmentally friendly method through a one-step hydrothermal low-temperature process without the use of surfactants. rGO was obtained by efficient reduction of GO with PEI (polyethylenimine), identified by XRD, and confirmed by FTIR, Raman, and XPS analyses. The XRD pattern shows the formation of CuS phase crystallized in a hexagonal structure, while the SEM image shows the growth of CuS nanocrystals on the rGO layer. TEM showed the formation of spherical CuS nanoparticles distributed on the rGO surface. When studying its electrochemical reaction, the synthesized nanocomposite exhibited pseudocapacitive behavior with a specific capacitance of 418 F g –1 .