Mitigation of clofibric acid pollution by adsorption: A review of recent developments

Clofibric acid (CA) is one of the recalcitrant pharmaceutical compounds observed as a pollutant in the environment in recent times. This paper aimed to evaluate the recent developments in the last decade on the mitigation of CA from aqueous media by adsorption. The adsorbents were classed into carbon-based materials, clay and minerals, and polymer and resins. It was observed that the best class of adsorbents (with adsorption capacity > 300 mg/g) for CA adsorption were carbon-based materials. The highest reported adsorption capacity for CA in the last decade was 994 mg/g by graphene nano-sheets. CA adsorption was mostly best fit to Langmuir or the Freundlich isotherm and kinetics was majorly according to the pseudo-second order model. CA can successfully be desorbed form adsorbent media by suitable eluents and reused. This suggests that adsorption can be economical in an industrial scale for the removal of CA from effluents. For future work, graphene oxide and metal organic frameworks could be modified for higher adsorption capacity. The disposal technique for used adsorbent after CA uptake could be explored.