Simultaneously enhanced photocatalytic and antibacterial activities of TiO2/Ag composite nanofibers for wastewater purification

Abstract

High throughput of polyacylonitile (PAN)-based Ag/TiO2 composite nanofibers were prepared by using needleless electrospinning method. The morphology and crystallinity characterization revealed uniform and smooth nanofibers with an average diameter ranged from 160 to 260 nm. The enhanced photocatalytic activity of PAN/Ag/TiO2 compared with PAN/TiO2 nanofibers under visible light irradiation was linked with high interfacial charge transfer and low bandgap due to Ag entity. High photodegradation efficiency for methyl orange, rhodamine B and methylene blue were achieved as 99.5%, 92% and 99% respectively during the 4 h experiment. Effect of key parameters (i.e. pH, oxygen and Ag/TiO2 loading dosage) on photodegradation efficiency of dyes were also investigated. Active species trapping experiments demonstrated that O2− and OH were dominant active species in the photocatalytic degradation of dyes. These composite nanofibers have also exhibited excellent antibacterial activity, e.g. 95% of E. coli and 99% of S. aureus were killed in 2 h. Bifunctional nanofibers can be easily recovered from the aqueous solution as compared with the TiO2 nanoparticles. Moreover, the daily production rate of nanofibers has reached over 1.4 kg in the laboratory test, which is 60 times higher than that using the single needle electrospinning method. This production rate may be further optimized in the pilot scale studies. High productivity and strong catalytic properties of nanofibers propose their potential applications in environmental remediation for economically and eco-friendly wastewater and air treatment materials.