Mitigation of Metronidazole (Flagyl) pollution in aqueous media by adsorption: a review

ABSTRACT In light of the changing consumption and lifestyle patterns, emerging contaminants such as pharmaceutical compounds in the ecosystem are now a cause for concern. Metronidazole (MNZ) also known as Flagyl is a popular antimicrobial, antibacterial and antiprotozoal. It has been reported in water bodies as an environmental pollutant. The aim of this paper was to review the research findings on the adsorption of MNZ from aqueous media to synthesise the research results and observe trends whilst pinpointing interesting areas for future work. It was observed from the review that activated carbon and metal–organic frameworks are the best class of adsorbents for the removal of MNZ from aqueous media. A wide range of values for the thermodynamic parameters (both negative and positive) has been reported for MNZ across different studies which were suggestive of the nature of the adsorbent being the important factor that determines the thermodynamics of MNZ adsorption. MNZ is capably desorbed by eluents like HCl and acetone but much work is still needed in this area. Gaps in knowledge abound in desorption studies, column/continuous flow adsorption studies, competitive adsorption studies and hybrid adsorptive processes. GRAPHICAL ABSTRACT