Piezoelectric porous α-quartz membrane by aqueous gel-casting with enhanced antifouling and mechanical properties

Porous alpha-quartz ceramics with improved mechanical strength were fabricated by using silica sol as a bonding agent in an aqueous gel-casting process. alpha-quartz dispersion was prepared with a solid load of 75 wt% and a viscosity of 1.66 Pa.s. alpha-Al2O3 particles were added to promote dispersion of the bonding agent. The optimum amounts of amorphous silica and alpha-Al2O3 were 10 % and 8 % of the mass of alpha-quartz powder, respectively. The thermal treatment of alpha-quartz green bodies was optimized for mechanical and permeation properties. Electrical fields up to 1 kV/mm were applied to the green bodies to accomplish alpha-quartz grains orientation and hence piezoelectric response. This caused an increase of piezo-acoustic response by 58 % at an excitation frequency of 200 kHz. In-situ mitigation of fouling was obtained by applying an alternating voltage of 60 V, during TiO2 suspension filtration, which resulted in an increase of the stationary flux by 23 %.