Treatment of carbamazepine and other structurally-related pharmaceuticals in water and wastewater by nanoporous adsorbents and photocatalysts: a critical review

Carbamazepine (CBZ) is a contaminant of emerging concern that is persistent in water and wastewater. At low concentrations, prolonged exposure to CBZ-containing water causes detrimental health effects to humans and may also have negative impacts on the environment. Here we critically review new treatment approaches to decrease CBZ concentrations in water and wastewater. First, we summarize the transformation pathways of CBZ in the aquatic environment and identify the corresponding products. Then, we describe the removal of CBZ and structurally-related pharmaceuticals by phototransformation, biotransformation, and adsorption processes, with an emphasis on the application of naturally- and biologically-derived nanoporous adsorbents, such as agricultural wastes, natural polymers, activated carbon, metal organic frameworks, silicas, and molecularly imprinted polymers. Biologically-derived activated carbons exhibited the highest adsorption capacities for CBZ, with adsorption predominantly occurring through hydrophobic and pi-pi interactions. CBZ was also effectively treated using titanium dioxide and other inorganic photocatalysts. This review not only provides a critical synthesis of state-of-the-art adsorption and degradation processes for CBZ and structurally-related pharmaceuticals, but also proposes knowledge gaps and future research directions.