Adsorption of paracetamol in contaminated water through pH-responsive polymer-brush-grafted mesoporous silica nanoparticles

This study investigated a process for removing paracetamol (PCM) from aqueous solutions using mesoporous silica nanoparticles (MSNs) grafted with pH-responsive poly(2-(tert-butylamino)ethyl methacrylate) brushes (PTBAEMA) via the surface-initiated atom transfer radical polymerisation technique on the inner and outer surface of the solid particles. The successful incorporation of PTBAEMA on the surface of MSNs was confirmed using XPS technique by a strong absorption peak at similar to 1750 cm(-1), which was assigned to - C = 0 stretching vibrations. The adsorption efficiency of MSN-PTBAEMA for PCM was studied as a function of different pH levels. The obtained results showed that the extraction efficiency of MSN-PTBAEMA for PCM was found to be about 92% higher when pH was in a range between 5 and 7. However, the adsorption efficiency of PTBAEMA-MSNs decreased to similar to 74% and similar to 38.6% at pH 9 with a PCM concentration of 100 ppm and 300 ppm, respectively. The maximum adsorption capacity of MSN-PTBAEMA for PCM was recorded at 237 mg/g. The Freundlich isotherms model was applied to the obtained adsorption data and suggested that a multilayer adsorption mechanism occurred on the surface of the adsorbent. In addition, the adsorption kinetics data was found to be best fitted with the pseudo second-order model, comparing to the pseudo first-order model. The obtained results confirmed that MSN-PTBAEMA could be effectively applied for the removal of PCM from the aqueous environments.