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

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2013-10, Vol.435, p.78-84
• Main Authors: Zhang, Hao, Xu, Meng, Wang, Hong-jie, Lei, Di, Qu, Dan, Zhai, Yu-jia
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; aqueous solutions; colloids; copper; Deltas; equations; Fourier transform infrared spectroscopy; Grafting; Heavy metals; Isotherms; Manganese dioxide; Mathematical analysis; Mesoporous materials; Organic silane; sorption isotherms; surface area; Surface chemistry; X-radiation; X-ray diffraction
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2012.12.037

[Display omitted] ► An aminopropyl functionalized mesoporous delta manganese dioxide (NH2-MnO2) was synthesized. ► Both of the adsorbing capability and selectivity of NH2-MnO2 for Cu(II) was enhanced by the process of aminopropyl functionalization. ► The adsorbing process of the NH2-MnO2 could occur more spontaneously and easily in nature than that of un-functionalized one. A novel adsorbent, named aminopropyl functionalized mesoporous delta manganese dioxide (NH2-MnO2), was synthesized by bounding 3-aminopropyltrimethoxysilane (APTMS) onto delta manganese dioxide (δ-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 δ-MnO2. The amount of APTMS grafted onto δ-MnO2 was found to be 1.640mmolg−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 79.31m2g−1, 0.19cm3g−1 and 9.52nm, 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 1.543mmolg−1, which was higher than that of the un-functionalized δ-MnO2 (1.220mmolg−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).