Scalable, high flux and durable electrospun photocrosslinked PVA nanofibers-based membrane for efficient water purification

Abstract

Membrane separation technology has received extensive attention in water purification. However, in practical applications, separation membranes still face challenges like complex preparation processes, high filtration energy consumption, and low flux. Therefore, in this study, the scalable, high-throughput and highly durable PVA-based nanofiber separation membranes has been manufacture by employing needle-free electrospinning technology. Subsequently, PVA nanofiber membranes with double-bond addition cyclopolymerisation were prepared through photocrosslinking, and their performance in advanced water purification was explored. The results indicated that through facile graft modification and the needle-free electrospinning method, the scalable PVA-based nanofiber membranes with a diameter of 270 nm can be produced. The production efficiency is around 15 g/h, which is obviously higher than that of the existing electrospinning process.Under 0.05 MPa, the pure water flux of the PVA-based nanofiber membrane could be maintained at a maximum of 4785.23 L/($m^{2}h$), and the interception rate was 99 % ($⩾$ 10 nm). When filtering lake water, the results indicated that the permanganate index in the lake water was significantly reduced to 1.05 mg/L ($⩽$ 3 mg/L), demonstrating excellent water purification performance. Importantly, the designed photocrosslinking is a convenient, low-energy and environmentally-friendly crosslinking process that can effectively control the degree of swelling of PVA nanofibers compared to traditional crosslinking techniques. Meanwhile, the process can effectively control the pore structure of PVA nanofiber membrane. This successfully solved the problems of easy dissolution and low filtration efficiency of PVA nanofiber membranes. This study opened up prospects for the efficient preparation of nanofiber separation membranes and their applications in water treatment.