Magnetic mesoporous carbon: efficiently reusable adsorbent for ionic liquid [Bmim]Cl from aqueous solution

Abstract

Magnetic mesoporous carbon composite (Fe/OMC) was synthesized and as an adsorbent for removal of ionic liquid, 1-butyl-3-methyl imidazolium chloride ([Bmim]Cl), from aqueous solution. X-ray diffraction, transmission electron microscopy analyses and nitrogen adsorption measurements revealed that the synthesized Fe/OMC composite retained ordered mesoporous structure. Meanwhile, nitrogen adsorption measurements indicated that the Fe/OMC possess relatively high surface areas (up to 651 m2 g−1), pore volumes (up to 0.66 cm3 g−1) and multimodal mesopore (3.48 and 4.85 nm) and micropore (1.47 and 1.85 nm) distributions of pore sizes. Magnetic measurement revealed the ferromagnetic property of Fe/OMC at room temperature with saturation magnetization value at 26.11 emu g−1 which implies that Fe/OMC composite could be separated by ferromagnet. Results of adsorption experiment showed that Fe/OMC composite was high-performance, easily recyclable adsorbent for ionic liquid, [Bmim]Cl, from aqueous solution. In addition, the Langmuir adsorption isotherm was applicable to the removal process; the maximum adsorption capacity value is 238.32 mg g−1. After eight recycle runs, the adsorption capacity was almost at the same value (238.32 mg g−1 for the first sorption and 228.21 mg g−1 for the eighth times sorption). An efficient magnetically separable sorbent for wastewater treatments was prepared and can be used to remove the ILs, [Bmim]Cl, from aqueous solution. Adsorption capacity of Fe/OMC adsorbent is good for adsorbing [Bmim]Cl after eight recycle runs. Furthermore, the recovered ionic liquid showed results similar to the fresh one.