In-situ air bubble for efficient membrane scaling cleaning with a catalytic nanofiber membrane in membrane distillation

Membrane scaling and subsequent membrane wetting pose significant impediments to the application of membrane distillation (MD) in treating high-salinity wastewater. This study introduces an innovative in-situ bubble cleaning strategy for the amelioration of membrane scaling in MD processes. A catalytic membrane was fabricated by introducing MnO 2 as a catalyst by electrospinning and the self-cleaning mechanism involving micro-nano bubbles and superhydrophobic surface was systematically investigated. Results showed that the fabricated MnO 2 /PVDF nanofiber membranes (M-FMP) showed superhydrophobic properties, with a water contact angle and rolling angle of 158° and 17°, which significantly improved the membrane's resistance to wetting and fouling. The M-FMP membrane exhibited exceptional performance across ten experimental cycles, achieving a flux recovery rate of over 92 % and demonstrating robust chemical stability following repeated cleanings with 0.006 wt% H 2 O 2 . Notably, CaSO 4 deposition on the M-FMP membrane was approximately 46.0 μg/cm 2 , accounting for only 14.6 % of the deposition observed on the M-P electrospun membrane. The in-situ cleaning process leveraging micro-nano bubbles proved to be significantly more effective than conventional ex-situ cleaning methods, offering superior performance in removing scale deposits. Overall, this pioneering in-situ catalytic self-cleaning approach offers a new option for controlling MD membrane scaling.