Sonophotolytic diethyl phthalate (DEP) degradation with UVC or VUV irradiation

Abstract

This study investigated the degradation of diethyl phthalate (DEP) by sonolytic, photolytic and sonophotolytic processes. Two types of UV lamps, UVC (254 nm) and VUV (185 nm+254 nm), were combined with ultrasound (283 kHz). The pseudo-first order degradation rate constants were in the order of 10(-1)-10(-3) min(-1) depending on the processes. The sonolytic DEP degradation rate increased with increasing applied power. Photolytic or sonophotolytic degradation of DEP when using a VUV lamp appeared to be effective because the photo ІІ (UVC/VUV) resulted in a significantly faster degradation than the photo І (UVC) processes due to the higher photon energy and higher hydroxyl radical generation by homolysis of water by VUV. Significant degradation and mineralization (TOC) of DEP were observed with the combined sonophotolytic processes. Moreover, synergistic effects of 1.68 and 1.23 were exhibited at DEP degradation of the sonophoto I and sonophoto II processes, respectively. This was attributed to the UV-induced dissociation of hydrogen peroxide (H(2)O(2)) generated by the application of US to hydroxyl radicals. Therefore, US in sonophotolytic processes can play an important role in enhancing DEP degradation. Moreover, the sonophoto ІІ process is more effective on the mineralization and biodegradability of DEP.

Biodegradation of Dimethyl Phthalate by Freshwater Unicellular Cyanobacteria

“…Due to the wide distribution, persistence, and difficulty in removal of PAEs, treatment approaches for PAEs-contaminated wastewater have attracted many researchers' attention [13–15]. Different methods for removing PAEs from the environment include physical, chemical, and biological treatments, advanced oxidation processes, and combinations of these techniques [16–20]. Unfortunately, these methods are limited in application because of the high cost.…”

Sonophotolytic degradation of phthalate acid esters in water and wastewater: Influence of compound properties and degradation mechanisms

“…Because of the large quantities of production and various losses/releases during manufacture, usage and disposal, PAEs are considered ubiquitous pollutants of the aquatic environment [15,16]. Many studies have been conducted concerning the degradation of individual PAEs using AOT methods [13,14,[17][18][19][20][21], and a few studies have also compared the degradation performance of a group of PAEs [3,16,22,23]. Although the physicochemical properties of different PAEs are sometimes used to describe their degradation performances, little systematic investigation has been conducted to relate the properties to the degradation performance, and particular for the US or US/UV processes.…”

Removal of Endocrine Disruptors from Urban Wastewater by Advanced Oxidation Processes (AOPs): A Review

“…More recent studies have been directed towards the combination of sonolysis with other processes, such as ultraviolet irradiation [46,47], photocatalysis [48], electrochemical processes [49]. The coupling of ultrasound with other processes was found to result in synergistic effects, leading to improved removal rates as well as to partial mineralization for a wide range of contaminants.…”