Revealing effect of heat transfer mode on the transformation of microstructure and properties of the nanofiltration membrane

[Display omitted] Heat curing is a critical process affecting the structure and properties of nanofiltration (NF) membranes. We investigated the effects of different heat transfer modes, specifically heat conduction and heat convection, on the NF membrane. Heat conduction slows down the heating rate, leading to a more stable temperature increase compared to heat convection. This trend affects the reactant diffusion rate during heat curing, resulting in a ridge-and-valley morphology on the membrane surface, which greatly improves the NF membrane permeability. We obtained an NF membrane achieving a flux of 56.2 L·h−1·m−2·bar−1 with a Na2SO4 rejection rate of 98.71 %. This work combines experimental analysis with numerical simulations to clarify the mechanisms of heat curing, providing a practical approach for designing high-performance NF membranes.