A novel semi-dry method for rapidly synthesis ZnO nanorods on SiO₂@PTFE nanofiber membrane for efficient air cleaning

Particulate matter including dust and airborne microorganisms has severe effect on indoor air quality and thus be injurious to human health. In this research, inspired by corals, a tentacle-like ZnO nanorods (NRs) decorated SiO₂@PTFE nanofibers was prepared by a novel semi-dry method combining rapid dipping and solid-phase drying process. The controllable growth of ZnO nanostructures can be achieved by adjusting the numbers of dipping cycles. It may be the most simple and effective way to prepare sufficiently crystallized ZnO nanostructures at relatively facile conditions without high temperature calcination and any pressure vessels. The obtained ZnO NRs-SiO₂@PTFE nanofiber membrane (NFM) with a hierarchical fibrous structure possesses uniform pore structure (average pore size 0.92 μm), high gas permeance (626.4 m³∙m⁻²∙h⁻¹∙kPa⁻¹), and a superior filtration property (99.997% for 0.3 μm particulates). Moreover, the active ZnO with enhanced specific surface also exhibits good antibacterial property with sterilization rate of 99.67% and 99.93% for E. coli and B. subtilis, respectively. The ZnO growth mechanism and air cleaning principle including dust filtration and bacteria sterilization were analyzed by the corresponding experiments. This work provides a new insight into the dual-function air cleaning membrane preparation via a mild and simple reaction conditions, energy efficient and environment friendly strategy.