Use of chalky algae in the manufacturing of clayey ceramic membranes: Microstructural and dielectric behavior for electrochemical applications

Novel ceramic membrane filters were manufactured from kaolino-illitic clays and calcareous algae (up to 20 wt.%) as porogenic agent. The produced membranes were investigated using X-ray diffraction, thermogravimetric analysis, scanning electron microscope, impedance spectroscopy, and Fourier-transform infrared spectroscopy. All of the filtration suitability, electrical properties, and dielectric behavior were assessed and interrelated to the microstructure. It was found that the original clay minerals were involved in the mineralization development while the inclusion of large pores (8–12 μm) was observed at high magnification alongside porosity increase (up to 70%) due to the addition of the bio-based pore-former. Both electric and dielectric measurements revealed that the sintering process was governed by the densification phenomenon and was accompanied with lower activation energy. The order of magnitude of the values taken by electrical impedance was close to average Mega-Ohms suggesting the suitability of the produced ceramic membranes as an electrical insulator for typical electrochemical devices. The tests of filtration have shown that the ceramic membranes produced operate normally in the microfiltration range for a period of 50 min without clogging and at pressures up to 0.12 bar. Conclusively, the developed ceramic membranes could be considered for applications in industrial wastewater treatment and electrochemical media.In addition to this, a perspective has been proposed on the improvement paths or designs for ceramic membrane filters with good performance in wastewater treatment present in some electrochemical environments as well as methods to cope with the challenges regarding the performance of such materials.