Electrospinning preparation and characterization testing analysis of nanofiber biofilms

In order to obtain a fibrous biofilm carrier material with a good water purification effect, the biofilm carrier of PAN and PAN-PEO (mass ratio 9:1) was prepared by the electrospinning process, and the performance differences between the fabric biofilm carriers of PAN, PAN-PEO (mass ratio 9:1), and blank non-woven fabric, including the structure of biofilm carriers (surface morphology, specific surface area, and porosity), surface wettability (water contact angle and water absorbance) and membrane hanging ratio, were tested through various characterization methods. The experimental results show that the nanofiber membrane of PAN and PAN-PEO (mass ratio 9:1) prepared by the electrospinning process has a diameter of 75–375 nm, a specific surface area of 19.2 m2/g, and a porosity of 80%. The fiber diameter of non-woven fabric is in the micrometer range, with a specific surface area of 0.3659 m2/g and a porosity of 60%. This indicates that the nanofiber biofilm of PAN and PAN-PEO (mass ratio 9:1) prepared by electrospinning belongs to the carrier with a small diameter, high specific surface area, and high porosity, which can provide more attachment sites and pores for micro-organisms and is more conducive to their attachment in wastewater treatment. At the same time, the water contact angles of PAN and PAN-PEO (mass ratio 9:1) are 27.97° and 18°, respectively, and the water absorption of both reached 300%. The water contact angle of non-woven fabric is 93.32°, and the water absorption rate is only 75%. This shows that the nanofiber biofilms of PAN and PAN-PEO (mass ratio 9:1) prepared by electrospinning effectively improve the infiltration of the carrier in sewage. Finally, under the same conditions, bacterial growth and biofilm growth experiments were conducted on the nanofiber biofilm carriers of PAN and PAN-PEO (mass ratio 9:1) and the biofilm carriers of non-woven fabric. It was found that the effectiveness of the PAN and PAN-PEO (mass ratio 9:1) nanofiber biofilm carrier was significantly higher than that of non-woven fabric in treating wastewater. After 3 days of bacterial cultivation, the membrane hanging ratio of the PAN nanofiber biofilm carrier was 90.36%, the membrane hanging ratio of the PAN-PEO (mass ratio 9:1) nanofiber biofilm carrier was 82.04%, and the membrane hanging ratio of the non-woven fabric biofilm carrier was only 27.32%. After 15 days of bacterial cultivation, the membrane hanging ratio of the PAN nanofiber biofilm carrier was 147.52%, the membrane hanging ratio of the PAN-PEO (mass ratio 9:1) nanofiber biofilm carrier was 147.52%, and the membrane hanging ratio of the non-woven fabric biofilm carrier was 110.53%.