The objective of this study was to prepare low-cost macroporous ceramic membranes using natural kaolin and natural lignite, as porogen agent, both from Tunisia. The characteristics of this membrane have been defined to be used in filtration processes and as a support for multilayer ceramic membranes. This study includes the characterization of the raw materials in order to define optimal processing parameters to obtain the membranes. A study of the effect of lignite content has been carried out. Porosity, density and mechanical strength were the considered parameters to be optimized. A lignite percentage of 20% and a sintering temperature of 1,050°C were chosen. Obtained membranes show good porosity above 43% but with a slightly low mechanical strength that does not exceed 20 MPa. These membranes can be considered as efficient regarding the results shown in the gas permeation tests.

Undoped and codoped (Eu/Na) ZnO nanocrystals (NCs) were successfully manufactured through an economical sol-gel method. X-ray diffraction (XRD) analysis demonstrated pure hexagonal wurtzite structure without secondary phases for all the samples. The size of the NCs was found to decrease with codoping by Eu³⁺/Na⁺ which is related to the existence of strain and stress in the lattice. The dominance of the E₂(high) mode in Raman spectra indicates the good crystallinity of the samples. The study from the X-ray photoelectron spectroscopy (XPS) shows the successful insertion of both Eu³⁺ and Na⁺ ions into the ZnO lattice and the generation of the zinc and oxygen vacancies (Vo) defects. The band gap energy was reduced and the Urbach energy increased with Na⁺ content, proving the distortion of the lattice. From the photoluminescence (PL) study, the activation of the Eu³⁺ ions by Na⁺ ones was evidenced. Longer PL lifetimes were obtained from Eu³⁺ ions when they were sensitized by Na⁺, which may be beneficial to several applications. A process of excitation transfer from both the ZnO host and Na⁺ sensitizers to the Eu³⁺ ions was evidenced and discussed. As an application, we tested the performances of the prepared NCs as photocatalysts for Rhodamine B photodegradation under sunlight irradiation. The ZnO NCs codoped with 1% Eu/4% Na displayed the best photodegradation rate with a good stability and a high kinetic rate constant k of 0.021 min⁻¹. The photocatalytic mechanism is discussed in terms of longer radiative recombination from Eu³⁺ and the generated oxygen vacancies.

In the present study, char and activated carbon (AC) materials were prepared from water bottles, recuperated from the waste collection point in Mourouj, Ben Arous, Tunisia, by using a rotative horizontal tubular furnace, on a lab/pilot scale and through chemical and physical activation. Different samples were characterized by N 2 adsorption isotherms, SEM-EDX, XRD, EA as well as by the determination of the pH zpc . The efficiency of the ACs to remove (2-methyl-4-chlorophenoxyacetic acid (MCPA) and 2,4-dichlorophenoxyacetic acid (2,4-D)) herbicides from aqueous solutions was also investigated. The results demonstrated that a maximum adsorption capacity of 192 mg · g - 1 , for MCPA, and 290 mg · g - 1 for 2,4-D had been attained. The adsorption kinetics was fitted to pseudo first, second order and Elovich model, while the adsorption isotherms were fitted applying the Langmuir and Freundlich isotherm models. The potential use as solid fuel materials was evaluated using elemental analysis and numerical high calorific value (HCV). The experimental results were compared to the conventional solid fuels classified in the Van Krevelen graph. The essays performed showed that the HCV was in the range of 10.2–11.9 MJ/kg.

Montmorillonite powder was treated by grinding, and then, it was subjected to acid leaching with variable concentrations of HCl for different periods of time. The effects of these two activations on the crystal structure, specific surface area, pore structure, and adsorption properties of the clay were explored by Fourier transform infrared spectra, X-ray diffraction (XRD), Brunauer–Emmett–Teller, and UV/visible techniques. An increase in surface area from 78 to 490 m²/g, specific micropore volume from 101.3 to 121.1 × 10⁻⁵ cm³/g has been attained. Factorial design was used to determine main factors affecting microstructure and textural properties of the activated clay. Based on the analysis of the factorial design of experiments, acid concentration was the most significant factor for the amelioration of specific surface area. The adsorption efficiency of activated sample for phenol was tested. It showed that the adsorption followed Langmuir isotherms and it was enhanced owing to the increase in specific surface area.