Piezoelectric membranes for electrically assisted microfiltration based on lead-free BCTZ: Processing and structure-performance relationships

Microfiltration (MF) membranes are widely used for water recovery from agro-food wastewater, but their performance is strongly limited by fouling, which reduces permeability and operating lifetime. Ceramic membranes provide higher chemical and mechanical stability than polymeric systems, yet their cost motivates the development of approaches that improve antifouling efficiency and extend service life. Piezoelectric ceramic membranes represent an emerging route in which electrically induced mechanical vibrations can promote foulant detachment and surface regeneration, enabling in in situ cleaning strategies. A key challenge is transferring piezoelectric functionality from dense ceramics to porous structures while retaining sufficient mechanical integrity and hydraulic permeability. This contribution reports first results on the relationships between microstructure and electromechanical response in porous lead-free (Ba,Ca)(Ti,Zr)O3 (BCTZ) membranes produced by sacrificial template processing, freeze casting, and binder jetting. These routes enable different pore size distributions, connectivity, and anisotropy. The effects of porosity and pore morphology on dielectric and piezoelectric properties are discussed, together with the role of poling conditions in activating the porous network. Preliminary filtration tests under electrical excitation are presented, correlating electrically driven actuation with antifouling behaviour through permeability as a performance indicator.