Photocatalytic degradation of dissolved organic matter under ZnO-catalyzed artificial sunlight irradiation system

Abstract

photocatalytic degradation of dissolved organic matter under ZnO-catalyzed artificial sunlight irradiation system thao thi nguyen, Seong-nam nam * , Jungryul Kim & Jeill oh * this study investigates the photocatalytic degradation of dissolved organic matter (DoM) under ZnO-assisted artificial sunlight system at various conditions (ZnO dosage, pH, and the presence of Cl − , So 4 2− , and HCO 3 −). The results show that the degradation of DOM follows a pseudo-first-order kinetics. fluorescence excitation-emission matrices coupled with parallel factor (eeM-pARAfAc) analysis decomposes DOM into two fluorophores (C1 and C2). The total removals and photodegradation rates calculated with Doc, UV 254 , and the f max of C1 are similar, increasing with higher ZnO dosages and being highest in pH 7 and lowest in pH 4. ZnO dosage has a similar effect on DOM degradation when assessed using C2, as with C1, but pH effect is not consistent. As for the anions, HCO 3 − shows the strongest inhibition for Doc, UV 254 and C1 while Cl − has the strongest facilitation effect for C2. the total removal and photodegradation rates calculated with the f max of C1 and C2 are higher than those calculated using Doc and UV 254. this study demonstrates that the successful application of eeM-pARAfAc analysis in addition to traditional parameters can provide further insight into the photocatalytic degradation mechanisms associated with DoM in conjunction with a Zno catalyst under artificial sunlight. Dissolved organic matter (DOM) is a heterogeneous mixture of aliphatic and aromatic polymers containing oxygen, nitrogen, and sulfur functional groups. DOM plays an important role in both natural and engineered water systems. The presence of DOM in aquatic environments can cause various problems such as the adsorption and deposition of organic foulants in membrane treatment processes and the formation of disinfection by-products (DBPs) 1-3. Humic acids (HAs), which are the main contributors to DOM, are well-known as a precursor to carcinogenic and mutagenic DBPs, such as trihalomethanes and haloacetic acid 4-6. HAs also turn water a brownish-yellow color, form complex species with metals and pesticides, increase the chlorine demand of water, cause corrosion in pipelines, and foul and plug membranes 4-6. The effective removal of DOM from water and wastewater is thus an important treatment objective and a major issue for water and wastewater treatment plants worldwide. Different treatment methods can be applied depending on the characteristics of the DOM, with the most common methods for DOM removal being coagulation, adsorption, membrane filtration, biological, ion exchange processes, and advanced oxidation processes (AOPs) 1-3. Of these methods, AOPs have been found to be particularly efficient. AOPs rely on the in-situ production of highly reactive hydroxyl radicals (• OH) with the help of one or more primary oxidants (e.g., ozone, hydrogen peroxide, or oxygen), energy sources (e.g. ultraviolet, solar, or visible light), and/or catalysts (e.g. WO 3 , ...

Evaluation of Sonocatalytic and Photocatalytic Processes Efficiency for Degradation of Humic Compounds Using Synthesized Transition-Metal-Doped ZnO Nanoparticles in Aqueous Solution

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