Selective Adsorption Behavior of Cu(II) and Cr(VI) Heavy Metal Ions by Functionalized Ordered Mesoporous Carbon

An ordered mesoporous carbon-silica nanocomposite was synthesized by the evaporation-induced triconstituent co - assembly method, wherein a soluble resol polymer was used as an organic precursor, tetraethoxysilane was used as an inorganic precursor, and the triblock copolymer F127 was used as the template. After the removal of silica with HF, ordered mesoporous pure carbon (OMC) was obtained. X-ray diffraction (XRD), N-2 adsorption-desorption isotherms (BET), and transmission electron microscopy (TEM) showed that the OMC product had a highly ordered structure with a large pore size of 6.4 nm, a pore volume of 2.13 cm(3).g-1, and a high surface area of 1330 m(2).g-1. The OMC was subsequently functionalized with ethylenediamine by treatment with nitric acid and thionyl chloride to obtain a functionalized ordered mesoporous carbon (C-NH2(m)), m is the mass (g) of the added ethylenediamine. Fourier transform infrared (FTIR) spectroscopy showed that the amino group was successfully grafted onto the surface of the OMC. TEM images showed that C-NH2(m) had a highly ordered mesoporous structure. OMC and C-NH2(m) were used as adsorbents for the selective adsorption of Cu(II) and Cr(VI) ions from the aqueous solution. C-NH2(9.0) had a higher adsorption capacity for Cu(II) of 495.05 mg.g(-1) versus 213.33 mg.g(-1) for the OMC and a lower adsorption capacity for Cr(VI) of 68.21 mg.g(-1) versus 241.55 mg.g(-1) for the OMC, indicating its significantly favorable potential for the selective adsorption of Cu(II).