Biomass-derived activated carbons for the removal of pharmaceutical mircopollutants from wastewater: A review

Biomass-derived activated carbons (biochars) have attracted great attention due to their excellent physicochemical properties such as high specific area, large pore volume, well-defined microporous structure and tunable surface chemistry. Although pharmaceuticals are an emerging class of micropollutants in wastewater through the sewerage disposal by pharmaceutical factories, hospitals and households, only a few recent studies have reviewed the adsorption and removal of pharmaceuticals from wastewater by biochars and they lack the systematic insights into total adsorption process from biochars preparation to adsorption mechanism. This paper aims to provide a comprehensive review on recent publications and to propose future research directions. The effects of lignocellulosic biomass as well as the pyrolysis, activation and modification conditions on the physicochemical properties of biochars and their adsorption capacities are discussed. The adsorption kinetics and isotherms of different pharmaceuticals onto various biochars are analyzed based on commonly used models. Finally, the potential adsorption mechanisms of pharmaceuticals by biochars are summarized.