Preparation of nitrogen-functionalized mesoporous carbon and its application for removal of copper ions

Abstract

Nitrogen-functionalized mesoporous carbon (NMC) materials with high nitrogen content were synthesized through a hard template method using ionic liquid of 1-cyanomethyl-3-methylimidazolium bromide as the precursor and LUDOX HS-40 colloidal silica as the template. The obtained NMCs were characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption and desorption analysis, X-ray photoelectron spectroscopy, and elemental analysis. It was shown that the carbonization temperature played a critical role in determining the physiochemical properties and the nitrogen content of the carbon materials. The obtained nitrogen-functionalized mesoporous carbon carbonized at 800 °C possessed disordered mesoporous structure with very high specific surface area of 1028 m2 g−1, large pore volume of 0.94 cm3 g−1, and high nitrogen content of 21.0 wt%. The adsorption performance of the prepared NMCs was investigated by removing Cu2+ from aqueous solutions and the adsorption capacity could attain 117.1 mg g−1 at an optimal condition. The kinetic and isothermal analysis revealed that the removal of Cu2+ by the NMCs belongs to chemical monolayer adsorption, suggesting the strong interaction between Cu2+ and the adsorbent. The XPS spectra of N1s before and after adsorption of Cu2+ suggested that the pyridinic-type nitrogen was the dominant groups of the adsorbent in the adsorption process. Furthermore, the material was separated from solution by filtration and displayed a superior reusability in the recycling test.