Fabrication,characterization and application of ceramic membrane developed from Tunisian natural kaolin clay for textile wastewater treatment are presented in this study.The morphology and properties of the resulting membrane sintered at 1000°C for 3 h was then determined by Scanning Electron Microscopy (SEM),mechanical and chemical resistance and water permeability.Separation performance of the membrane was evaluated during treatment of textile wastewater.SEM images reveal homogeneous surface of the membrane.The membrane displayed good chemical and mechanical resistances as well. Its permeability was of 21.2 L.h -1 .m -2 .bar -1 , indicating that separation performance could occur in the domain of Ultrafiltration(UF).Performances of the membrane during the treatment of raw and biologically pretreated textile effluents are promising in terms of removal of color (99% for the raw effluent and 100% for the biologically pretreated effluent), chemical oxygen demand (COD) (80% for the raw effluent and 93% for the biologically pretreated effluent) and turbidity (98% for the raw effluent and 100% for the biologically pretreated effluent).

Asymmetric mesoporous composite PTFE membranes wit 40, 50, and 85 wt.% of a clay (kaolin) were fabricated and characterized using a scanning electron microscope equipped with EDX for morphology and elemental analysis. The surface chemistry of the membranes was checked using Fourier transform infrared spectroscopy. The effect of incorporating the clay on the hydrophilicity, permeability, morphology, and antifouling properties of the fabricated membranes was investigated. It was observed that incorporating kaolin particles improved the mechanical properties but decreased the contact angle of the membranes, thereby resulting in an improvement in the membrane permeability. The performance of the three composite UF membranes was evaluated through the treatment of a real textile effluent sample containing indigo dye. The results confirmed that these membranes are effective in the removal of COD, color, and turbidity. Indeed, at a transmembrane pressure of 2.5 bar, almost total removal of the turbidity, COD removal > 85%, and color removal > 97% were attained. Furthermore, membrane A85 (with 85% clay) showed the best performance, with a water flux of 659.1 L·h−1·m−2·bar−1. This study highlights the potential of incorporating low-cost clay material for the enhancement of the performance of mixed organic/inorganic matrix membranes, which can be applied to textile wastewater treatment.

In the present work, we propose the use of the Laser Scanning Confocal Microscopy (LSCM) to determine the effect of water repellents on rock's pore-network configuration and interconnection. The rocks studied are sandstones of Miocene age, a building material that is commonly found in the architectural heritage of Tunisia. The porosity quantitative data of treated and untreated samples, obtained by mercury porosimetry tests, were compared. The results show a slight decrease in total porosity with the water repellent treatment, which reduced both microporosity and macroporosity. This reduction produced a modification in pore size distribution and a shift of the pore access size mode interval toward smaller pore diameters (from the 30-40 microm to the 20-30 microm intervals). The water repellent was observed in SEM images as a continuous film coating grain surfaces; moreover, it was easily visualized in LSCM, by staining the water repellent with Epodye fluorochrome, and the coating thickness was straightforwardly measured (1.5-2 microm). In fact, the combination of mercury intrusion porosimetry data and LSCM observations suggests that the porosity reduction and the shift of the pore diameter mode were mainly due to the general reduction of pore diameters, but also to the plugging of the smallest pores (less than 3-4 microm in diameter) by the water repellent film. Finally, the LSCM technique enabled the reconstruction of 3D views of the water repellent coating film in the pore network, indicating that its distribution was uniform and continuous over the 100 microm thick sample. The LSCM imaging facilitates the integration and interpretation of mercury porosimetry and SEM data.

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