Synergy of adsorption and advanced oxidation processes in recalcitrant wastewater treatment

The presence of recalcitrant organic pollutants in water is a major source of concern worldwide. These pollutants are not easily removed using conventional treatment technologies. Integrating adsorption with advanced oxidation processes is an effective technology for removing recalcitrant pollutants. Here, we review the synergy of adsorption and advanced oxidation processes. We discussadsorption-Fenton, adsorption-photocatalysis, ultrasound-adsorption and adsorption-Ozonation. We note an increasing use of composites with dual functions as adsorbents and catalysts in photocatalysis and heterogeneous Fenton oxidation. Ultrasound irradiation is combined with adsorption to enhance mass transfer through cavitation. However, the contribution of cavitation-induced radicals has not been quantified. While previous studies have given more emphasis on the synergy of the combined processes in pollutants removal, we have highlighted herethe potential of the oxidation processes to regenerate spent adsorbents.