A review of the application of sonophotocatalytic process based on advanced oxidation process for degrading organic dye

Abstract

Nowadays the use of conventional wastewater treatment methods is becoming increasingly challenging mainly due to the presence of organic matter in wastewater. Therefore, an emerging technology is needed to deal with these highly concentrated and toxic non-biodegradable organic matters. In the last few decades, advanced oxidation process (AOP) has emerged to treat wastewaters discharged from industries. Recently, researchers have shown interest to use the application of ultrasound (US) in photocatalysis, i.e. sonophotocatalysis, to improve the performance of the treatment process in the degradation of organic and inorganic contaminants in aqueous streams. Sonophotocatalysis is the combination of the use of ultraviolet (UV) and US.

Hydrogen peroxide enhanced sonophotocatalytic degradation of acid orange 7 in aqueous solution: optimization by Box–Behnken design

“…However, the US process may cause flaws on the surface of TiO 2 increasing the number of activated sites, which can enhance the efficiency of photocatalytic degradation of organic pollutants 35 . The addition of H 2 O 2 significantly improved AO7 degradation of the US‐UV/TiO 2 system, because it could produce ∙ OH under US and UV irradiation directly 2 . In addition, the ∙ OH could also be generated from H 2 O 2 in the conduction band of TiO 2 .…”

“…In recent years, sonophotocatalysis [coupling of photocatalysis and ultrasound/sonolysis (US)] as one of several advanced oxidation processes (AOPs) has been applied effectively for pollutant degradation 1‐3 . Compared with other advanced oxidation processes, the degradation of pollutants in the sonophotocatalytic processes could be attributed to radical generation from the valence and conduction bands of semiconductors under UV irradiation and the sonochemical oxidation process under US 2,4 . Some typical photocatalytic semiconductors such as titania (TiO 2 ), zinc sulfide (ZnS), tin dioxide (SnO 2 ), copper oxide (CuO) and niobium pentoxide (Nb 2 O 5 ) were investigated and showed effective catalytic performance 5,6 .…”

“…Among these oxidants, H 2 O 2 is a good oxidant as it has a strong oxidizing capacity and simple working principle, can eliminate mass transfer limitations, and is abundant and safe in use for the environment. The addition of H 2 O 2 to TiO 2 ‐based sonophotocatalysis (US‐UV/TiO 2 ) will enhance the generation of ˙OH and subsequently support higher pollutant degradation according to the following equations 1‐4,10,12,13 Hydrogen peroxide is a commonly used oxidant in AOPs, 14 but its use in sonophotocatalysis is rarely reported.…”

Effect of turbidity on ultraviolet disinfection of domestic wastewater for agricultural reuse

“…This has promoted indirect reuse of wastewater without prior planning or treatment (Oliveira et al, 2019). However, after proper treatments, the reuse of effluents is an alternative to meet water demands of the agricultural sector, in which large amounts of freshwater are used (Zewde et al, 2019). Disinfection is considered a tertiary treatment, with emphasis on chlorination, ozonation, reverse osmosis, membrane filtration, and ultraviolet (UV) radiation (Collivignarelli et al, 2018).…”

“…The purpose of UV sterilization is eliminating or inactivating microorganisms such as bacteria and viruses (Chhetri et al, 2018). UV radiation has been increasingly used in wastewater treatment in the last 25 years because of little contact time and high antimicrobial activity (Masschelein et al, 1989;Guo et al, 2009;Zewde et al, 2019).…”