Visible-light sensitization of TiO2 photocatalysts via wet chemical N-doping for the degradation of dissolved organic compounds in wastewater treatment: a review

Abstract

Increased pollution of ground and surface water and emerging new micropollutants from a wide variety of industrial, municipal, and agricultural sources has increased demand on the development of innovative new technologies and materials whereby challenges associated with the provision of safe potable water can be addressed. Heterogeneous photocatalysis using visible-light sensitized TiO 2 photocatalysts has attracted a lot of attention as it can effectively remove dissolved organic compound in water without generating harmful by-products. On this note, recent progress on visible-light sensitive TiO 2 synthesis via wet chemical N-doping method is reviewed. In a typical visible-light sensitive TiO 2 preparation via wet chemical methods, the chemical (e.g., N-doping content and states) and morphological properties (e.g., particle size, surface area, and crystal phase) of TiO 2 in as-prepared resultants are sensitively dependent on many experimental variables during the synthesis. This has also made it very difficult to provide a universal guidance at this stage with a certainty for each variable of N-doping preparation. Instead of one-factor-at-a-time style investigation, a statistically valid parameter optimization investigation for general optima of photocatalytic activity will be certainly useful. Optimization of the preparation technique is envisaged to be beneficial to many environmental applications, i.e., dissolved organic compounds removal in wastewater treatment.

Highly efficient photocatalytic degradation of methylene blue by P2ABSA-modified TiO2 nanocomposite due to the photosensitization synergetic effect of TiO2 and P2ABSA

“…1,2 However, the wide band gap (3.2 eV) of TiO 2 limits its visible light utilization, while its low quantum efficiency (<20%) restricts electron-hole separation, which generates reactive oxygen species (ROS) to degrade organic pollutants. 3,4 Many approaches, such as metal/ nonmetal doping, noble metal deposition, and dye sensitization, have been attempted to enhance the photocatalytic performance of TiO 2 by improving its photoresponse and quantum efficiency. [5][6][7] Recently, conducting polymers, such as polyaniline (PANI), polythiophene (PTh), poly-o-phenylenediamine (PoPD), and their derivatives, have been reported as promising modiers for TiO 2 photocatalysts.…”

Efficient Bacteria Inactivation by Ultrasound in Municipal Wastewater

“…On the other hand, advanced oxidation processes (AOPs) have demonstrated high removal efficiencies, but with a focus on oxidation of dissolved organic matter, especially persistent organic pollutants [6,7]. One of the most viable is heterogeneous photocatalysis using titanium dioxide or zinc oxides as catalysts.…”

Synthesis of Surface Oxygen-deficient BiPO4 Nanocubes with Enhanced Visible Light Induced Photocatalytic Activity

“…Although TiO 2 is the most promising photocatalyst and is widely investigated due to its non-toxicity, chemical stability and low cost, low solar energy conversion efficiency and high recombination of photogenerated electron-hole pairs make it difficult for practical applications 5,6 . Therefore, it is necessary to fabricate efficient new types of photocatalysts capable of responding to visible light in order to improve the utilization of solar energy.…”