Gradient-Functionalized Pet Filter with Side-Emitting Polymer Optical Fibers for Triplex Synergistic Air Purification: Photocatalytic Degradation, Particulate Filtration, and Antimicrobial Performance

Abstract

This study presents a gradient-functionalized PET-based fixed-bed air filter for synergistic removal of volatile organic compounds (VOCs), particulate matter (PM), and pathogens indoors via polydopamine (PDA) biomimetic adhesion, rGO-TiO₂ photocatalytic systems, and side-emitting polymer optical fibers (POF). The mechanism of key parameters’ influence on formaldehyde degradation was analyzed through gradient and cooperative experiments. Systematic experimental optimization determined the optimal preparation concentrations of GO and TiO₂ at 0.05 g/L and 20 g/L, respectively. Using a dual factor orthogonal design, the filter configuration with 61 POFs, 4 mm POF diameter, 0.5 m/min filtration velocity, and 60 PPrT layers achieved a formaldehyde degradation efficiency of 91.21% with a photocatalytic quality factor of 0.0507 within 300 minutes, along with a particle removal efficiency of 99.89 to 100% for particles ranging from 0.3 to 10 μm with a filter quality factor between 0.139 and 0.282. Dynamic shielding effects induced by particulate deposition were systematically investigated. After 6 particulate-loading cycles, the filter maintained a formaldehyde degradation efficiency of 89.37% and a particulate matter filtration efficiency of 98.69 to 100%, confirming its regenerative capability. These results indicate that PDA modification enhanced the stability of the catalyst. Additionally, the filter achieved greater than 99.56% removal of E. coli aerosols, with the third PPrT layer exhibiting 99.78% bacterial inactivation within 60 min under photocatalytic activation. This study develops a practical method for fabricating multifunctional PET filters using nonwoven PET fibers integrated with POFs for ultraviolet delivery, achieving concurrent formaldehyde degradation, aerosol filtration, and antibacterial performance.

Keywords: Gradient-functionalized design, PET-based air filter, Polydopamine, rGO-TiO₂ photocatalysis, Side-emitting polymer optical fiber