Preface Free

Water is one of the most valuable resources on our Earth, and it ensures human survival and supports the development of human civilization. However, a safe and stable water supply has become intensively precious nowadays. The natural water body contains a large number of waste materials and/or by-products from human activities and industrial production, among which organics are one kind of typical pollutants in wastewater. Organic pollutants widely exist in municipal, industrial and agricultural wastewater, and they are toxic, persistent and easily transferred, posing a great challenge to in-depth decontamination. Even worse is the organic pollution from industrial wastewater in some developing countries.

Integrating advanced oxidation processes (AOPs) before or after biological degradation is one of the most effective strategies for organic wastewater treatment because of the merits of the fast and complete destruction of the aqueous organics into nontoxic products by the generated active species at relatively low cost. Until now, various AOPs have been developed, among which Fenton reaction and ozonation prove to be the most promising technologies for practical application. Ozonation can be operated in mild conditions without secondary pollution, yet ozone shows a selectivity in organics oxidation that hinders its broad application. To intensify ozonation efficiency, heterogeneous catalysts are fabricated, and a series of additional technologies/substances, such as photocatalysis, hydrogen peroxide, electric field, membrane and nanobubbles, are incorporated. The added chemicals or energy either greatly accelerates ozone transformation to reactive oxidative species or enhances the mass transfer of ozone, ultimately boosting efficiencies in organics mineralization and/or disinfection. These combined processes bring a new outlook to the traditional ozonation technologies, and this topic has received widespread attention all over the world, especially in the field of wastewater treatment. It is the right time to popularize the state-of-the-art coupled ozonation technologies for advanced water and wastewater treatment.

For this book, we invited scientists from several countries who have been working on wastewater treatment with ozone for years to give a comprehensive and in-depth illustration of advanced ozonation processes for organic wastewater treatment. This book includes 12 chapters on intensified ozonation technologies and the corresponding mechanistic insights, which are catalytic ozonation processes with various heterogeneous catalysts (metal oxides, supported metal oxides and carbonaceous materials), ultraviolet- and visible-light-assisted photocatalytic ozonation, catalytic peroxone, electroperoxone, ultrasound-assisted catalytic ozonation, hybrid ceramic membrane–assisted catalytic ozonation and nanobubble-enhanced ozonation processes.

Addressing climate change has become a major concern of humankind and requires the mitigation of total carbon emissions by upgrading the heavy-emission processes. Coupled ozonation processes have demonstrated their superiority over time- and energy-consuming traditional processes in water decontamination. By summarizing their recent developments and the underlying mechanisms, this book is expected to facilitate the application of the effective coupled ozonation processes and stimulate the development of cost- and energy-efficient water purification technologies in order to create a sustainable future.

Hongbin Cao, Yongbing Xie, Yuxian Wang, Jiadong Xiao