A Review of Titanium Dioxide (TiO2)-Based Photocatalyst for Oilfield-Produced Water Treatment

Abstract

Oilfield produced water (OPW) has become a primary environmental concern due to the high concentration of dissolved organic pollutants that lead to bioaccumulation with high toxicity, resistance to biodegradation, carcinogenicity, and the inhibition of reproduction, endocrine, and non-endocrine systems in aquatic biota. Photodegradation using photocatalysts has been considered as a promising technology to sustainably resolve OPW pollutants due to its benefits, including not requiring additional chemicals and producing a harmless compound as the result of pollutant photodegradation. Currently, titanium dioxide (TiO2) has gained great attention as a promising photocatalyst due to its beneficial properties among the other photocatalysts, such as excellent optical and electronic properties, high chemical stability, low cost, non-toxicity, and eco-friendliness. However, the photoactivity of TiO2 is still inhibited because it has a wide band gap and a low quantum field. Hence, the modification approaches for TiO2 can improve its properties in terms of the photocatalytic ability, which would likely boost the charge carrier transfer, prevent the recombination of electrons and holes, and enhance the visible light response. In this review, we provide an overview of several routes for modifying TiO2. The as-improved photocatalytic performance of the modified TiO2 with regard to OPW treatment is reviewed. The stability of modified TiO2 was also studied. The future perspective and challenges in developing the modification of TiO2-based photocatalysts are explained.

Enhancing the physical properties and photocatalytic activity of TiO2 nanoparticles via cobalt doping

“…7 Many synthesis techniques, such as co-precipitation, hydrothermal, sol-gel, wet chemical, and chemical vapour deposition, have been used to synthesize TiO 2 nanostructures. 8 Among them, the co-precipitation chemical method is a facile, economical, and valuable synthesis route. It was used in the current report to synthesize Co-doped TiO 2 nanoparticles.…”

Immobilization of a TiO2–PEDOT:PSS hybrid heterojunction photocatalyst for degradation of organic effluents

“…Titanium dioxide (TiO 2 ), being one of the promising semiconductor photocatalysts, is widely used to degrade many organic pollutants and is highly rated due to its catalytic reactivity, physical and chemical stability, nontoxicity and lowcost. [1][2][3][4][5] In conventional wastewater treatment processes, TiO 2 nanoparticles (NPs) are directly dispersed in the effluent solution, providing a high catalyst surface area which reacts with the pollutant. 6 However, this mechanism possesses some practical technical challenges.…”

Visible-Light-Driven Photocatalytic Coupling of Neat Benzylamine over a Bi-Ellagate Metal–Organic Framework

“…Nonetheless, semiconductors with a distinguished photocatalytic activity may form upon electronic excitation during light-induced photocatalytic process . Semiconductors including metals such as bismuth, , titanium, , or manganese , have been tremendously used as active photocatalysts for different applications. Among these, bismuth-based materials such as bismuth vanadate (BiVO 4 ), , bismuth oxycarbonate (Bi 2 O 2 CO 3 ), and bismuth oxyhalides (BiOX, X = Cl, Br, and I), , have a superior photocatalytic activity under visible light irradiation, which is attributed to the narrow band gap energy (<3.0 eV) caused by the distributed electrons in the VB …”