Recent advances on magnetic carbon-related materials in advanced oxidation processes of emerging pollutants degradation

Abstract

Recently, carbon-related materials have been proposed to improve the charge separation of the photogenerated carriers in the semiconductor matrices’ and surface properties. Carbon-related materials may act as co-catalysts, enhancing the pollutants adsorption on the surface, improving the charge carriers separation and photocatalyst stability and providing more active centres for photocatalytic reactions. This review summarizes recent advances in the preparation and environmental application of carbon-related materials. The focus was set on preparation of carbon-related materials and magnetic carbon-related photocatalytic materials with the property of easy separation after the purification process in an external magnetic field and their application for degradation of emerging pollutants not susceptible to biodegradation. The present studies identify four main groups of water pollutants: pesticides, pharmaceuticals, industrial chemicals, and heavy metals. Among them, pharmaceuticals and phenolic compounds represent a significant group of persistent organic pollutants. Some of the commonly used pharmaceuticals for human health, as well as disinfectants, are found in wastewater influents and effluents (after the purification process) almost in the unchanged form. Their detection in trace amounts (of about a few micrograms to hundreds of nanograms per litre) and removal become difficult but important because they put at risk the reuse of treated wastewater and the sustainability of water cycle management. Concerning levels of concentrations, these compounds are classified as hazardous due to possibilities of bioaccumulation, biomagnification and toxic impact on living organisms, even in trace amounts. Up to now, various methods have been reported in the removal of pharmaceuticals and phenolic compounds from aqueous systems.

Heterogeneous photocatalysis belonging to the group of advanced oxidation processes (AOPs) is one of the most promising methods used for the degradation of emerging pollutants. Introducing carbon-related materials modified by magnetic ferrites can significantly improve the efficiency of emerging contaminants' degradation. This review provides coherent information for future studies in the application of carbon-related materials and magnetic carbon-related materials for the removal of active pharmaceutical ingredients and phenolic compounds. Insights on pharmaceutical and phenolic compounds photodegradation in the presence of carbon-based materials combined with magnetic ferrites and their combination with SR-(AOPs) and Fenton-type photocatalysis are for the first time discussed. Moreover, the effect of various parameters such as water matrice, pH, natural organic matter presence, and temperature were also discussed. Finally, the economic feasibility and consideration of photocatalyst recovery capability completed the concept and discussion on magnetic carbon-related materials.