About this Research Topic
The high standards for drinking water quality set by the European Union and the World Health Organization, as well as the high toxicity of certain organic and inorganic pollutants, make the existing technologies for the purification of industrial wastewaters or ground/drinking water unsatisfactory. That is why the immediate development of new technologies for the elimination of such persistent pollutants from industrial wastewaters and ground waters becomes imperative. In addition, human consumption of certain categories of substances, such as pharmaceuticals, has increased exponentially during the last couple of decades, with the environment to be especially burdened from their rejection. Several studies have been reported that prove the existence of pharmaceuticals in aquatic ecosystems. More specifically, residues of antibiotics, which constitute a significant percentage of the pharmaceuticals consumed worldwide, were found in surface waters, groundwaters, seawater, drinking water, WWTP effluents, and hospital wastewaters. In the case of persistent inorganic pollutants, such as nitrate/nitrite ions, numerous treatment methods have been examined, which can be divided into physico-chemical, biological and catalytic processes.
Catalytic technologies have been paid increasing attention in refractory pollutant abatement (both organic and inorganic) due to its practical and potential values in water purification. Although some quite effective and efficient approaches for water purification (mainly elimination of organic pollutants), like Fenton-based technologies, ozonation, electrochemical and chemical methods have been widely studied and a few applied in some specific cases, there is still a lot of progress that needs to be achieved, particularly regarding specific types of organic or inorganic pollutants, such as pharmaceutical residues and nitrate ions.
In recent years, some novel heterogeneous catalytic and photocatalytic technologies have been developed for enhancing the efficiency of removing specific persistent pollutants from water (e.g., pharmaceuticals and nitrates).
The scope of this Research Topic is to emphasize on the recent developments in heterogeneous catalytic and photocatalytic processes used for the elimination of these refractory organic and inorganic pollutants. Such novel catalytic technologies may include the advancement/ improvement or even combination of contemporary processes, as well as innovative technologies based on completely new concepts, like the use of reduction processes (e.g., using a reducing gas) for the detoxification (elimination of ecotoxicity) of pharmaceutical residues. Special attention will also be paid on efficient technologies for the reduction of inorganic pollutants such as nitrates in water (or wastewater), a problem that has not yet been treated successfully by any of the catalytic technologies/systems examined so far (in terms of practical application).
This collection also attempts to shed light on the general and specific mechanisms and principles governing the heterogeneous catalytic and photocatalytic degradation or detoxification of persistent organic and inorganic pollutants.
Keywords: Water and Wastewater Purification, Catalytic Technologies, Pharmaceutical Residues, Denitrification, Xenobiotics, Photocatalytic Oxidation, Catalytic Hydrogenation
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