High efficiently removal of Cd(II) in environmental water samples by nano-particle supported ionic liquid material

Abstract

Ionic liquids have been considered as green solvent for metal ion extraction. However, the high cost, low efficiency and hard phase separation limit their application. In this work, nano SiO2 supported ionic liquid (SiO2@NH-IL) prepared via simple homogeneous sol-gel method was used for adsorptive removal of Cd(II) from water sample. The material was characterized by XRD, TEM and FT-IR and zeta potential analysis. The adsorption kinetics, adsorption isotherm and reusability as well as the adsorption mechanism were investigated. The effects of solution pH and temperature were also studied. It was found that this nano-adsorbent could be used to remove trace level of Cd(II) efficiently due to the strong coordination of Cd(II) with the ionic liquid. Thermodynamic and kinetic studies showed that the adsorption rate increased with the increase of temperature, the maximum adsorption capacity was 112.13 mg g−1 at higher temperature (i.e. 80 °C), and the adsorption equilibrium could achieve in 30 min. The nano-adsorbent could be easily regenerated by 0.5 mol L−1 of HCl and reused as least ten adsorption/desorption cycles. The as-prepared nano-adsorbent are potential candidate for adsorptive removal of Cd(II) in polluted wastewater, especially with higher temperature.