Abstract
Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most common pharmaceuticals used worldwide. They are widely detected in natural waters due to their persistence in wastewater treatment, and their removal is desirable in wastewater management. As a contribution to tackle this challenge, this study explores magnetic quaternary chitosan-based nanosorbents for the effective magnetically assisted removal of three NSAIDs (diclofenac, naproxen, and ketoprofen) from water. Toward this goal, silane groups were grafted onto the backbone of trimethyl chitosan through the reaction with an epoxide functionalized silane. Once silanized, the modified chitosan was employed to coat Fe3O4 nanoparticles. The prepared materials were characterized using FTIR spectroscopy and solid-state 29Si and 13C NMR spectroscopy, which confirmed the encapsulation of Fe3O4 nanoparticles with a hybrid siliceous material enriched in trimethyl chitosan. The effect of the initial NSAIDs concentration, pH, and contact time in the adsorption behavior was investigated. The kinetic data were well described by the pseudo-second-order kinetic model, indicating a chemisorption mechanism. The maximum adsorption capacities estimated from the Langmuir model were 188.5 mg/g (0.5925 mmol/g), 438.1 mg/g (1.7371 mmol/g), and 221.5 mg/g (0.8710 mmol/g) for diclofenac, naproxen, and ketoprofen, respectively. These adsorption capacities are higher than those of most reported sorbents, indicating the potential of these biosorbents to remove the selected NSAIDs using low-energy magnetically assisted separation.
Highlights
Water pollution is one of the most critical environmental problems that the world urgently needs to address, since clean water is vital for every living organism [1]
The powder X-ray diffraction (XRD) pattern of the particles used as cores (Figure 1a), along with the labelling of the respective Miller indices, indicated the presence of magnetite (Fe3O4) with cubic inverse spinel structure (JCPDS file No 19-0629) [37]
A similar XRD pattern was observed for the Fe3O4@SiO2/trimethyl chitosan (TMC)/GPTMS particles, confirming that after surface modification, the composition of the core of the particles was maintained as Fe3O4
Summary
Water pollution is one of the most critical environmental problems that the world urgently needs to address, since clean water is vital for every living organism [1]. In the European Union (EU), about 3000 different substances are used for human medication purposes that are highly persistent in the environment and are of toxicological concern [3]. These chemicals are considered emerging pollutants because their discharge limits in the environment still remain unregulated or are in the process of regularization [4,5]. NSAIDs undergo several processes during wastewater treatment, but they are not entirely removed from water using conventional procedures [6,10] This contributes to the occurrence of high levels of NSAIDs in aquatic environments, reaching values as high as μg/L concentration at multiple locations worldwide [6,11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
