Removal behaviour of NSAIDs from wastewater using a P-functionalised microporous carbon

Diclofenac (DCF), naproxen (NPX) and ibuprofen (IBF) are three of the most commonly used nonsteroidal anti-inflammatory drugs (NSAIDs) worldwide. They are widely detected in natural waters due to their persistence in wastewater treatment, and their removal is desirable in future wastewater management worldwide. In this study, acid catalyst functionalisation and subsequent carbonisation were adopted to synthesise a P-doped microporous carbonous adsorbent (CScPA) for NSAID removal. The CScPA was evaluated in depth for its adsorption performance (i.e., isotherms, kinetics and thermodynamics of adsorption at lab-scale). The CScPA had a large surface area (791.1 m(2)/g) and good porosity (0.392 cm(3)/g), which facilitated a high maximum adsorption capacity of 62.02 mg/g for a NSAID mixture. Thermodynamic data indicated that the adsorption of these NSAIDs was an endothermic process determined by physisorption (low-energy interactions). XPS analysis revealed the specific interactions involved in the adsorption process, including pi-pi and pi-pi electron donor-acceptor (EDA) interactions and hydrogen (H-) bonding. The Freundlich isotherm and Elovich kinetic model provided the best fit to the experimental results, which indicated surface heterogeneity (of the CScPA) and cooperative adsorption mechanisms. The adsorption process was shown to have potential to be applied to real wastewater effluent containing NSAIDs at low environmentally relevant concentrations (removal reached > 90% at 10 mu g/L). Analysis of different implementation and cost related factors suggested that the CScPA has the potential for use with real-world water matrices, offering a sustainable treatment process for pharmaceutical remediation in wastewater. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study synthesized a P-doped microporous carbonous adsorbent (CScPA) for the removal of NSAIDs. The CScPA showed a large surface area and good porosity, enabling a high adsorption capacity. Thermodynamic data indicated an endothermic adsorption process, and experimental results suggested surface heterogeneity and cooperative adsorption mechanisms.