Fresh water scarcity and water pollution are an enormous challenge for humanity. A sufficient availability of fresh and clean water is crucial for the environment, human health and the economy. The re-use of treated wastewater has a huge potential in the industrial sector. Especially if thereby intake of fresh water can be reduced, contributing to sustainable (process) development. Unfortunately, non-biodegradable organic compounds are problematic and difficult to remove. Advanced oxidation processes (AOP) are promising technologies and capable to remove such organic compounds, due to their highly oxidative power. Consequently, applying these technologies holds the potential to further improve the quality of treated wastewater. The research project described in this thesis aims at a better understanding and further development of two AOP technologies and related materials for saline wastewater treatment. In particular, photocatalytic degradation treatment of wastewater using UV illuminated TiO2 slurries and electrochemical degradation treatment by anodic formation of oxidizing species, such as OH and Cl radicals (also known as electrochemical advanced oxidation process (EAOP)), have been studied in detail. The thesis consists of seven chapters including five chapters describing the main results. Chapter one gives a general introduction to water scarcity, pollution and treatment, especially with focus on photocatalytic and electrochemical degradation. In chapter two and three, the influence of salt on the mineralization or organic compounds and formation of undesired chlorinated intermediates and byproducts is studied during photocatalytic and electrochemical degradation treatment of synthetic and real wastewater from cooling tower blowdown. Chapter four and five describes a method for electrochemical defect engineering of TiO2, which is considered as promising electrode material. In particular, the influence of the counter electrode along with related contaminations and the effect of Nb-doping on the electrochemical modification of TiO2 is studied. In chapter six electrochemical reduction of hypochlorite and chlorate is studied as a post-treatment to remove the undesired oxychlorides and lower the toxicity of electrooxidized saline wastewater. A summary of the research and perspective is described in chapter seven.
|Qualification||Doctor of Philosophy|
|Award date||18 Sep 2020|
|Place of Publication||Enschede|
|Publication status||Published - 22 Sep 2020|