Solar-Powered Photodegradation of Pollutant Dyes Using Silver-Embedded Porous TiO2 Nanofibers

Abstract

Titanium dioxide (TiO2) nanomaterials have been ubiquitously investigated as a photocatalyst for organic contaminant treatment in wastewater due to their exemplary semiconductor properties. However, their huge band gap remains a barrier for visible light absorption, limiting their utility in practical applications. The incorporation of noble metals in the TiO2 scaffold would help mitigate the problem via plasmonic resonance enhancements. Silver (Ag) is the chosen noble metal as it is relatively cheap and has great plasmonic effects. In this study, the use of electrospun Ag-embedded TiO2 nanofibers as a photocatalyst is shown to be effective in decomposing rhodamine B and methyl orange dyes under a solar simulator in 3 h, which is more efficacious as opposed to pristine TiO2 nanofibers. This showcases the potential of a simple and economic wastewater treatment system for the removal of organic pollutants.

Prospects of Synthesized Magnetic TiO2-Based Membranes for Wastewater Treatment: A Review

“…The presence of dissolved oxygen (DO) is critical in TiO 2 photocatalysis. The DO ensures that there are enough electron scavengers present to aid in the trapping of the excited conduction-band electrons during the recombination step [18,51,77]. The presence of DO has no effect on the adsorption onto the TiO 2 catalyst surface since the reduction reaction occurs at several sites separate from where the oxidation occurs.…”

“…The presence of DO has no effect on the adsorption onto the TiO 2 catalyst surface since the reduction reaction occurs at several sites separate from where the oxidation occurs. The DO influences the formation of reactive oxygen species, the stabilization of radical intermediates, mineralization, and direct photocatalytic reactions [77]. The total amount of DO produced in a reactor is determined by a few factors such as the environmental condition, the catalyst type and concentration, the contaminant, and so on [80].…”

“…The development of visible/solar light-active photocatalysts has been a continued effort in recent years [19,25,77,78]. Some of these photocatalysts have been synthesized and their efficacy in wastewater treatment has been determined.…”

“…Modification of TiO 2 with promising results has been reported as a solution. Some researchers have worked on incorporating activated carbon, graphite, graphene oxide, nanosheets, and other elements into TiO 2 while others have focused on the incorporation of various metallic and nonmetallic additives [18,19,25,51,77,79,80]. Furthermore, doping metals and nonmetals into conventional photocatalysts enhances photoreactivity, and thus quantum efficiency, by altering the intrinsic and surface properties in a favorable approach [51].…”

Fabrication and Photocatalytic Properties of Electrospun Fe-Doped TiO2 Nanofibers Using Polyvinyl Pyrrolidone Precursors

“…For this reason, in the case of anatase TiO 2 with a bandgap of 3.2 eV, only a short wavelength no longer than 387.5 nm can be used for the reaction, which means that 95% of the sunlight incident on the earth cannot be used. Because these factors directly reduce the efficiency of the photocatalyst, various methods have been proposed to solve these issues, including elemental doping [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ], dye sensitization [ 24 , 25 , 26 ], and microstructure control [ 27 , 28 , 29 ]. In the case of elemental doping, the dopant acts as a trap for excited electrons or holes, which delays the recombination of electron–hole pairs.…”