Impact of water matrix on the removal of micropollutants by advanced oxidation technologies

Abstract

Micropollutants (MPs) in the aquatic compartments originate from many sources and particularly from the effluents of urban wastewater treatment plants (UWWTPs). Advanced oxidation technologies (AOTs) usually applied after biological processes, have recently emerged as effective tertiary treatments for the removal of MPs, but the oxidation rates of the single compounds may be largely affected by the constituent species of the water matrix. These species include dissolved organic matter and inorganic species (e.g., carbonate, bicarbonate, nitrite, sulphate, chloride). This review analyses the impact of such substances on common AOTs including photolysis, UV/H2O2, Fenton, photocatalysis, and ozone-based processes. The degradation efficiency of single MPs by AOTs results from the combined impact of the water matrix constituents, which can have neutral, inhibiting or promoting effect, depending on the process and the mechanism by which these water components react. Organic species can be either inhibitors (by light attenuation; scavenging effects; or adsorption to catalyst) or promoters (by originating reactive oxygen species (ROS) which enhance indirect photolysis; or by regenerating the catalyst). Inorganic species can also be either inhibitors (by scavenging effects; formation of radicals less active than hydroxyl radicals; iron complexation; adsorption to catalyst or decrease 2 of its effective surface area) or promoters (e.g., nitrate ions by formation of ROS; iron ions as additional source of catalyst). The available data reviewed here is limited and the role and mechanisms of individual water components are still not completely understood. Further studies are needed to elucidate the wide spectrum of reactions occurring in complex wastewaters and to increase the adoption of AOTs in UWWTPs.

Enhanced removal of antibiotics in hospital wastewater by Fe–ZnO activated persulfate oxidation

“…At neutral pH, TiO 2 surface is positively charged (point of zero charge pH = 6.20), 46 and thus able to sorb effectively anionic ligands species. 9 In case of FLU (pKa = 6.5), more FLU adsorption to TiO 2 results in better photocatalytic activity (k app = 0.264 h -1 ) compared to Fe-ZnO (Fig. 8).…”

“…[47][48][49] The binding of LHA compounds to metal-oxides may poison the catalyst surface and/or scavenge radical species. 9,50 The dissolved iron concentration measured in solution at the end of oxidation run showed a very low release of Fe from Fe-ZnO (i.e. < 0.1 µM).…”

“…[6][7][8] Although these compounds often co-exist with other inorganic and organic compounds, most of previous works have mainly focused on removal processes in monocomponent systems, and in pure water or synthetic contaminated waters. 9 In order to remove antibiotics from wastewaters, advanced oxidation processes has attracted great attention through generation of reactive oxygen species (ROS). [9][10][11] Among these processes, photocatalysis has been widely used in order to remove organic compounds in contaminated waters.…”

“…9 In order to remove antibiotics from wastewaters, advanced oxidation processes has attracted great attention through generation of reactive oxygen species (ROS). [9][10][11] Among these processes, photocatalysis has been widely used in order to remove organic compounds in contaminated waters. This process involves irradiation of semiconductor such as TiO 2 or ZnO, and when energy photons are greater than the width of semiconductor gap band, electronic gaps (commonly called holes and noted h + and electron overload noted e‾) are created.…”

Adsorption and Rejection of PAEs by Modified Nanofiltration Membrane

“…At present, the main methods to remove PAEs from water include biodegradation [8], advanced oxidation [9], and JOURNAL OF Engineering Science and Technology Review www.jestr.org Jestr r membrane separation [10]. Chi et al [11] selected three species of marine microalgae to evaluate the tolerance and biodegradation of two typical PAEs (diethyl phthalate (DEP) and dibutyl phthalate (DBP)).…”