Vermiculite supported ionic liquids for diclofenac sodium removal: Radiation synthesis, structure, and adsorption at high pH and high-salt media

Diclofenac sodium (DCF) as an important emerging pollutant has raised significant environment concerns, but conventional adsorbents presented dramatic decline in adsorption capacity under high pH and high salt media. In this work, a vermiculite (VMT) nano-sheet supported ionic liquids (ILs) material was synthesized by two-step involving acid activation and radiation induced grafting 1-vinyl-3-hexylimidazolium tetrafluoroborate onto the VMT (V n -IL, n means the molar concentration of HCl). The V n -IL exhibits above 95% adsorption efficiency at alkaline media. The adsorption isotherms are well obeyed the Langmuir model, with maximum adsorption capacity of DCF onto V n -IL (n=1, 2, 4) determined as 234.75, 245.09 and 255.76 mg/g, respectively, indicating that the adsorption was chemical process. The adsorption efficiency of Vn-IL for DCF was almost not changed, even the concentration of NaCl was 10,000-fold higher than that of DCF. The removal efficiency exhibited negligible reduction after five cycles of regeneration, thereby confirming the stability and recyclability of Vn-IL in DCF elimination.