Adsorption of copper by aminopropyl functionalized mesoporous delta manganese dioxide from aqueous solution

A novel adsorbent, named aminopropyl functionalized mesoporous delta manganese dioxide (NH2-MnO2), was synthesized by bounding 3-aminopropyltrimethoxysilane (APTMS) onto delta manganese dioxide (delta-MnO2)surface and used as Cu(II) adsorbent in aqueous solution. The Fourier transform infrared spectroscopy (FT-IR) results verified the grafting of APTMS onto delta-MnO2. The amount of APTMS grafted onto delta-MnO2 was found to be 1.640 mmol g(-1) by thermo gravimetric analysis (TGA). X-ray powder diffraction (XRD) indicated the poorly-crystalline structure of the adsorbents. The specific surface area, pore volume and Barrett-Joyner-Halenda (BJH) pore diameter of the NH2-MnO2 were 79.31 m(2) g(-1), 0.19 cm(3) g(-1) and 9.52 nm, respectively. The adsorption isotherm at 298K could be well described by Langmuir isotherm equation. The maximum adsorption capacity of NH2-MnO2 for Cu(II) at pH 4.0 was 1.543 mmol g(-1), which was higher than that of the un-functionalized delta-MnO2 (1.220 mmol g(-1)). The Elovich equation fitted well for the Cu(II) adsorbing process by NH2-MnO2. The process of aminopropyl functionalization enhanced the adsorbing capability of NH2-MnO2 for Cu(II). (C) 2013 Elsevier B.V. All rights reserved.