Preparation of ionic liquid-functionalized layered double hydroxide via thiol-ene click chemistry for highly efficient removal of azo dyes during broad pH range

A novel 1-propylene-3-methylimidazolium chloride ([AMIM]Cl) ionic liquid-functionalized Mg/Al layered double hydroxide (IL-LDH) was synthesized via a thiol-ene click reaction and applied to adsorb Congo Red (CR) from aqueous solution. The structure of the prepared adsorbent was characterized mainly using X-ray diffraction (XRD), infrared spectrum (IR), thermogravimetric analysis (TGA), and N 2 Brunauer-Emmett-Teller surface area measurements. Batch adsorption experimental factors including initial pH, the amount of adsorbent and adsorption time were investigated. Under optimal conditions, the maximum adsorption capacity of CR on IL-LDH was 288.63 mg·g −1 , which was higher than that of Mg-Al-LDHs intercalated with sodium dodecylsulfate (LDH-SDS) (90.86 mg·g −1 ). In addition, the adsorption of CR on IL-LDH had no obvious change when initial pH values were changed from 5.0 to 10.0, which indicated the adsorbent was pH-independent. Based on the above results, ionic liquid-modified layered double hydroxide may constitute a potential adsorbent for water purification .