Electrospun-based TiO₂ nanofibers for organic pollutant photodegradation: a comprehensive review

Abstract

Titanium dioxide (TiO2) is commonly used as a photocatalyst in the removal of organic pollutants. However, weaknesses of TiO2 such as fast charge recombination and low visible light usage limit its industrial application. Furthermore, photocatalysts that are lost during the treatment of pollutants create the problem of secondary pollutants. Electrospun-based TiO2 fiber is a promising alternative to immobilize TiO2 and to improve its performance in photodegradation. Some strategies have been employed in fabricating the photocatalytic fibers by producing hollow fibers, porous fibers, composite TiO2 with magnetic materials, graphene oxide, as well as doping TiO2 with metal. The modification of TiO2 can improve the absorption of TiO2 to the visible light area, act as an electron acceptor, provide large surface area, and promote the phase transformation of TiO2. The improvement of TiO2 properties can enhance carrier transfer rate which reduces the recombination and promotes the generation of radicals that potentially degrade organic pollutants. The recyclability of fibers, calcination effect, photocatalytic reactors used, operation parameters involved in photodegradation as well as the commercialization potential of TiO2 fibers are also discussed in this review.

Comparative study of photocatalytic activity of metals- and non-metals doped ZnO and TiO2 nanocatalysts for advanced photocatalysis

“…Many researches have investigated the impact of reaction time on the photodegradation efficiency of organic contaminants using TiO2 and ZnO photocatalysts. The longer the reaction time, the higher the photodegradation efficiency of the contaminant [40]. According to the work done by Shi et al (2019), eliminating MO using TiO2/chitosan increased with enhancing the reaction time and finally reaches equilibrium.…”

“…Basic dyes are cationic dyes and most of them are crystalline compounds, which can be derived from positively charged sulfur or nitrogen atoms. Under visible and UV light irradiation, dyes have high stability and insensitivity, and do not degrade without photocatalyst [38][39][40]. Cationic, anionic and non-ionic are 3 important categories of dyes, among which, the toxicity of cationic dyes is more than the other two.…”

“…On the other hand, it prevents light from penetrating into the sewage. As a critical result, an optimal value of catalyst must be determined to prevent overuse of the catalyst and to achieve maximum degradation efficiency [40].…”

“…Industrial effluents may be discharged at different pHs, which complicates the photocatalytic reaction. Also, hydroxyl radicals are rapidly eliminated at high pHs, inhibiting their reaction with the contaminant [40,115]. There are many effective factors on pH in the photocatalytic reaction, including electrostatic charge of catalyst particles, band structure, and crystals size.…”

In situ growth of Cs3Bi2Br9 on ultrathin BiVO4 nanosheets to fabricate heterojunction intimate interfaces for enhancing photocatalytic activity

“…Nevertheless, the degradation efficiency is still unsatisfactory owing to their inherent defects (e.g., large optical bandgap) and severe electron-hole recombination. 10,17 Accordingly, there is an urgent need to develop cost-effective, stable, and high-performance photocatalysts to optimize the activity of organic dye degradation.…”