High-flux bacterial cellulose ultrafiltration membrane with controllable pore structure

Nanocellulose membranes have attracted widespread attention because of its nano pore size, environmental friendliness, hydrophilicity and biocompatibility. However, the low water permeation, weak wet strength and high bacterial adhesion limit their pratical application. Herein, an ultrafiltration membrane based on bacterial cellulose (BC) with high flux, high wet strength and antibacterial property was prepared by using nano silica as porogen and polyhexamethylene guanidine hydrochloride (PHGHE) as both crosslinker and fungicide. Without affecting the uniformity of the membrane, a high dosage of nano silica was conducted to construct straight-through channels in the membrane Z direction, which greatly reduces the actual capillary tube length and increases the flux. The effective pore size was successfully controlled below 90 nm and the flux reached a high level of 7147 L·m−2·h−1·bar−1. After PHGHE modification, the wet strength of the BC membrane increased by 4.5 times (up to 4.47 MPa) as well as significantly improved the antibacterial performance (zone of inhibition=15.0–15.2 mm). The underwater superoleophobicity and nanoscale pore size make it excellent at separating nanoparticles and nanoemulsions with sizes even lower than 100 nm in aqueous solutions. The developed high flux BC membrane would have wide applications in wastewater separation and purification.