Porous Electrospun Fibers Embedding TiO₂ for Adsorption and Photocatalytic Degradation of Water Pollutants

Abstract

Using a bipolymer system consisting of polyvinylpyrrolidone (PVP) and poly(vinylidene fluoride) (PVDF), P25-TiO was immobilized into thin film mats of porous electrospun fibers. Pores were introduced by dissolving sacrificial PVP to increase surface area and enhance access to TiO. The highest photocatalytic activity was achieved using a PVDF:PVP weight ratio of 2:1. Methylene blue (MB) was used to visualize contaminant removal, assess the sorption capacity (5.93 ± 0.23 mg/g) and demonstrate stable removal kinetics ( k > 0.045 min) under UVA irradiation (3.64 × 10 einstein/cm/s) over 10 cycles. Treatment was also accomplished via sequential MB sorption in the dark and subsequent photocatalytic degradation under UVA irradiation, to illustrate that these processes could be uncoupled to overcome limited light penetration. The photocatalytic mat degraded bisphenol A and 17α-ethynylestradiol in secondary wastewater effluent (17 mg TOC/L), and (relative to TiO slurry) immobilization of TiO in the mat mitigated performance inhibition by co-occurring organics that scavenge oxidation capacity. This significantly lowered the electrical energy-per-order of reaction (EEO) needed to remove such endocrine disruptors in the presence of oxidant scavenging/inhibitory organics. Thus, effective TiO immobilization into polymers with affinity toward specific priority pollutants could both increase the efficiency and reduce energy requirements of photocatalytic water treatment.

Visible Light Photocatalytic Functional TiO2/PVDF Nanofibers for Dye Pollutant Degradation

“…Another point of difference is the color change; the color of RhB changed from red to transparent. However, Cossich et al's research did not mention about the color change, and the color of MB changed from blue to gray with all MB completely degraded in Lee et al's research . One further point of difference is 80% of RhB in our research was degraded quickly, with the reminding 20% degrading slowly under visible light.…”

“…The peak area of methylene blue at 662 nm gradually decreased until disappearing after irradiation by UV light for 120 min. Lee et al used PVP/TiO 2 /PVDF with PVP to PVDF of 1:2 to degrade methylene blue under UV irradiation. The result showed that the color of MB changed from light blue to purple after 240 min immersion of nanofibers in 3 mg L −1 MB solution under darkness.…”

“…One further point of difference is 80% of RhB in our research was degraded quickly, with the reminding 20% degrading slowly under visible light. The three previously mentioned research studies possessed fast and stable degradation rates under UV lights …”

Core‐sheath structured TiO2@PVDF/PAN electrospun membranes for photocatalysis and oil‐water separation

“…Therefore, it is needed to develop a feasible, professional, and effective method to separate oil and water. Photocatalytic water treatment achieves oxidative degradation of many organic pollutants using light irradiation without chemical addition . Titanium dioxide (TiO 2 ) is considered to be an ideal photocatalysis that has been commonly studied due to its high activity, strong chemical stability, nontoxicity, low production cost, photocatalytic properties, and self‐cleaning capability .…”

Synthesis and characterization of Ag‐loaded p‐type TiO2 for adsorption and photocatalytic degradation of tetrabromobisphenol A

“…Additionally, with a range of doping and heterojunctions, TiO 2 can be used to degrade various organic pollutants under UV–visible (λ > 360 nm) or visible light (λ > 420 nm) as well. However, the main pollutants that are targets for degradation are dyes and phenol‐like organic pollutants (Lee et al, ; Likodimos, ; Xing et al, ; Zada et al, ; Zalfani et al, ; Zhang, Li, Li, Li, & Yang, ). Studies on the degradation of emerging contaminants (ECs) under UV–visible or visible light are few.…”