Synthesis and application of SBA-15 adsorbent for the removal of organic and inorganic substances.

This study investigates the adsorption of pollutants with different chemical structures; organic Naphtol Green B (NGB) dye and copper on a nanocomposite material with a hexagonal structure of the SBA-15 type. This research is divided into two main parts: the first carries out the synthesis of SBA-15 (Santa Barbra Amourphous) and its derivatives phases functionalized by 3-aminopropyl-triethoxylane (APTES) and calcined at 823 K. The second part presents the influence of the adsorption conditions on the adsorption efficiency of NGB dye and copper. High-resolution X-ray diffractogram (XRD) showed three distinct peaks characteristic of highly ordered mesoporous material. Nitrogen adsorption-desorption isotherm of SBA-15 at 77 K° is type IV typical of mesoporous materials. In addition, Fourier transform infrared spectroscopy (FT-IR) was also used in the characterization before and after the adsorption of the selected pollutants. At optimal conditions of pH 5.2, initial concentration of 50 mg/L, adsorbent dosage of 20 mg, and at adsorption time of 90 min the maximum removal of pollutants reached 76% and the adsorption capacity was 227.25 mg/g for NGB dye and 221.006 mg/g for copper. Furthermore, the adsorption kinetics followed the pseudo-second-order model, indicating that chemisorption was the dominant mechanism and the Sips isotherm model best described the adsorption data. Our research demonstrates that the SBA-15 material after modification is an effective adsorbent for removing effluents regardless of their different chemical structure (organic and inorganic).

Synthesis of nickel-based layered double hydroxide (LDH) and their adsorption on carbon felt fibres: application as low cost cathode catalyst in microbial fuel cell (MFC).

Following their successful utilization as novel bioanodes in Microbial Fuel Cells (MFCs), Layered Double Hydroxide (LDH) were tested in the present investigation, as promising cathodes to reduce electrons coming from oxidation of organic matter in the anode compartment, in the presence of oxygen used as successful oxidant. Therefore, the LDH samples Ni3Al-LDH with the ionic ratio Ni2+/Al3+ equal to 3, were synthesized and added by adsorption to Carbon Felt (CF) fibres. They were then stored separately in three electrolyte solutions KCl, NiCl2 and AlCl3 used as catholytes in the MFCs. Effects of the active cationic sites located inside the Ni3Al-LDH on these electrolytes, were discussed in terms of energies produced by these MFCs. The structure and morphology of the synthesized LDH, were studied by using the analytical techniques XRD, FTIRS and SEM, while the electrode performances of the LDH-electrodes were investigated with the electrochemical methods CV and EIS. It was revealed that the CF modified with Ni3Al-LDH cathode and conditioned in the NiCl2 electrolyte solution yielded the highest energy harvesting for the MFC (i.e. 3.2 µW/cm2). This power density output was similar to previous clean one-compartment MFC. However, it was less expensive than an Enzymatic Fuel Cell (45 µW/cm2), making in evidence the highest cost of the material. Thus, by taking into account these encouraging findings, the low cost materials used in MFCs held great promise for practical application in electrochemical power devices and therefore fruit waste treatment. Abbreviations: ACFC: Air Cathode Fuel Cell; ADEFC: Alkaline Direct Ethanol Fuel Cell; AFC: Alcaline Fuel Cell; BET: Brunauer-Emmett-Teller; BFC: Biological Fuel Cell; CF: Carbon Felt; CV: Cyclic Voltammetry; DGFC: Direct Glucose Fuel Cell; DMFC: Direct Methanol Fuel Cell; EFC: Enzymatic Fuel Cell; EIS: Electrochemical Impedance Spectroscopy; FC: Fuel Cell; FTIR: Fourier Transform Infra Red spectroscopy; LDH: Layered Double Hydroxide; MEC: Microbial Electrolysis Cell; MFC: Microbial Fuel Cell; Mg-Al- CO 3 2 -LDH: Layered Double Hydroxide Magnesium-Aluminium-Carbonate; Ni-Al-LDH: Layered Double Hydroxide Nickel-Aluminium; OCP: Open Circuit Potential; SEM: Scanning Electron Microscope; TG/DTA: ThermoGravimetric and Differential Thermal Analysis; XRD: X-Ray Diffraction.