Magnetic graphene oxide modified by chloride imidazole ionic liquid for the high-efficiency adsorption of anionic dyes

Abstract

Magnetic graphene oxide modified with 1-amine-3-methyl imidazole chloride ionic liquid (LI-MGO) was prepared through chemical co-precipitation and modified using 1-amine-3-imidazolium chloride ionic liquid. The as-prepared LI-MGO was characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectrometry (FT-IR). The adsorption properties were evaluated through adsorption experiments with two kinds of anionic dyes, orange IV (OIV) and glenn black R (GR) and two kinds of cationic dyes, acridine orange (AO) and crystal violet (CV). The results indicated that the adsorption data fitted the Langmuir isotherm and followed pseudo-second-order kinetics. The maximum adsorption capacities for GR, OIV, AO and CV were 588.24, 57.37, 132.80 and 69.44 mg g⁻¹ at 298 K, respectively. LI-MGO has better selective adsorption for anionic dyes than magnetic graphene oxide (MGO) due to electrostatic interactions. Moreover, the LI-MGO adsorbent can be magnetic separated and is easy to prepare. It demonstrated that LI-MGO would have great potential as an efficient environmentally friendly adsorbent for the removal of anionic dyes in water treatment.