Stable and effective photo-Fenton catalysts of Fe-alginate/PVDF composite electrospun nanofibers for the removal of methylene blue

Wastewater containing organic pollutants has created serious environmental issues and severely threatened human health due to the industry’s rapid development. Fenton processes, among the most economical advanced oxidation methods, can efficiently decompose and completely mineralize organic pollutants. Fenton processes have been widely employed in wastewater treatment to remove organic dyes; however, their practical application is limited due to the secondary pollution of Fe sludge. This work used the electrospinning technique to create Fe-alginate/PVDF nanofibers with a mass ration of 1:0.3, followed by iron ion exchange (0.08 wt%) as a photo-Fenton catalyst. The catalytic degradation of 20 mg/L methylene blue revealed that Fe-alginate/PVDF nanofibers (10 mg) had remarkable photo-Fenton catalytic performance, degrading 97.24% of methylene blue within 40 min under optimized conditions (pH of 3, H₂O₂ concentration of 0.20 mM). Additionally, the wetting property and the development of the Fe-alginate coordination structure prevented iron leaching and strengthened the Fe-alginate/PVDF nanofibers’ structure stability, thus limiting secondary pollution of wastewater during application. Moreover, Fe-alginate/PVDF nanofibers could effectively remove MB over a wide pH range of 3.0–9.0, applied to the majority industrial wastewater (neutral or slightly acidic pH conditions). This work provides a facile strategy to prepare stable and cost-effective heterogeneous photo-Fenton catalysts, demonstrating potential applications in industrial-scale wastewater treatment.