Removal of diclofenac from wastewater: A comprehensive review of detection, characteristics and tertiary treatment techniques

The increase in the consumption of diclofenac (DCF), the incorrect disposal of this pharmaceutical and the low efficiency of removal in wastewater treatment plants result in the detection of this emerging contaminant in different environmental compartments, especially in water resources. DCF can be toxic for several organisms according to its concentration. In this sense, the present review presents the occurrence of DCF in aqueous matrices around the world, the main characteristics of this contaminant and some alternative methods for DCF removal from synthetic aqueous media and real effluents, such as adsorption, membrane separation, and advanced oxidation processes. A bibliometric and systematic approach was performed to systematize the state-ofthe-art of the last 10 years, using Scopus as a database. It was concluded that the techniques presented are effective to DCF treatment, since a removal efficiency of up to 100% was found in the literature reviewed for each sole treatment. However, these techniques present limitations related to the large-scale efficiency, high costs, intermediate compounds production, and complexity of the mechanisms of action. The integration of technologies is a promising alternative to overcome these limitations, but the implementation of a coupled system must consider several factors, especially for real effluents. Finally, we show how the advances in DCF techniques removal from aqueous matrices can positively impact several Sustainable Development Goals (SDGs) of the United Nations.