Effect of the addition of the calcareous algae on the microstructural properties and filtration performances of membranes manufactured from Ghassoul Moroccan clay

Abstract Cordierite based membranes were elaborated from a naturally Moroccan clay (Ghassoul) and algae as porosity agent (10 wt%). Specimens devoid of algae were also manufactured and used as reference samples (B1 & B2). To obtain the stoichiometry of cordierite, alumina and silica gel were added to the employed clay. After calcination at 600 °C, the mixture was heat treated according to two different thermal cycles. The first one consisted of a single thermal treatment at 1250 °C after the addition of the algae (BAL1). As for the second, two heat treatments were carried out at 1250 °C separated by the addition of the algae BAL2. Several techniques were used to characterize the cordierite membrane performances such as X-ray diffraction, thermal analysis, scanning electron microscope, Fourier-transform infrared spectroscopy and microscope impedance spectroscopy. Porosity and filtration suitability were assessed and correlated to the morphology. It has been proved that stevensite, dolomite and quartz were involved in the neoformation process and melt respectively. SEM examinations showed different features that exhibited different sized pores alongside with some melted zones. Algae addition contributed to the formation of pores in algae containing samples compared to the reference specimens. At room temperature, filtration tests were performed using textile effluent in order to reduce the turbidity, BOD and the chemical oxygen demand. The results showed that their percentages decreased by more than 60% after filtration. In addition, dielectric measurements revealed that the sintering process was effective beyond 1000 °C and it was accompanied with a low activation energy. Manufactured ceramic membranes are expected to have challenge application in the treatment of wastewater.