Adsorptive removal of paracetamol from aqueous media: A review of adsorbent materials, adsorption mechanisms, advancements, and future perspectives

Pharmaceuticals are emerging contaminants that have physiological effects on aquatic life even at trace amounts. Paracetamol (acetaminophen) is one of the most used analgesics and antipyretics for the treatment of fever and pain. Its detection in different water bodies has raised a concern around the globe, necessitating a need for its efficient removal from water. Over the last few years, researchers have synthesized and employed a wide range of materials for adsorptive remediation of paracetamol. In this review, we critically reviewed the role of such materials in paracetamol removal along with the effect of different uptake parameters and removal mechanisms. Special emphasis has been placed on providing a plausible mechanism for the uptake of paracetamol in terms of macroscopic, empirical modeling, spectroscopic, density functional theory and artificial neural networks analysis. The key mechanisms of paracetamol uptake involve hydrogen bond formation, van der Waals forces, n-π, π-π, and electrostatic interactions. In many of the reported studies, pseudo-second-order kinetics and Langmuir isotherm models were commonly fitted to paracetamol uptake data. The testing of such adsorbents in real wastewater and their regeneration has been specially discussed. A comparative overview of a wider range of adsorbents revealed that carbonaceous and agriculturally derived materials have promising performance. Finally, this review reports useful findings, challenges, and prospects for better efficiency of the adsorbents, and it will be beneficial for researchers interested in the development of novel adsorbents for the removal of paracetamol from real environmental and industrial water.