A novel, green method for the preparation of biodegradable PLA membranes without pore-forming agent

Polylactic acid (PLA) membranes have attracted significant attention in separation technologies due to their biodegradable properties. This study proposes a novel and eco-friendly pore-forming strategy for fabricating PLA membranes by triggering the in situ reaction between CaCO₃ nanoparticles and citric acid during the phase inversion process. Unlike conventional methods requiring synthetic pore-forming additives, this approach leverages the sacrificial role of CaCO₃ and the reaction-generated CO₂ nanobubble to synergistically construct a porous structure. The overall porosity increases from 70.2 % (pristine PLA membrane, M0) to 85.6 % (membrane prepared from a 6 wt% CaCO₃-containing casting solution, M6), while pure water flux rises dramatically from 20.1 L·m⁻²·h⁻¹ to 218.3 L·m⁻²·h⁻¹, with bovine serum albumin rejection maintained at 96.8 %. Furthermore, the flux recovery rate improves from 53.2 % (M0) to 71.2 % (M6), demonstrating enhanced antifouling properties. This entirely green fabrication process, employing only natural CaCO₃ and citric acid, represents a significant advancement in sustainable membrane technology and provides a viable route for developing high-performance biodegradable separation membranes.