Preparation of amino-functionalized mesoporous silica (MCM-41) for Nitrate anion adsorption from aqueous solution

In this study, mesoporous silica MCM-41 material was synthesized using simple method at room temperature, and then loaded it with amine group by grafting method. MCM-41 was characterized by means of atomic force microscopy (AFM), X-ray diffraction (XRD), BET surface area; Thermal Gravimetric Analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. Then the ability of MCM-41 as adsorbents to treat NO3 anion as inorganic pollutant from synthetic wastewater was investigated. Batch adsorption was employed to determine the effects of initial concentration (25-150 mg/L), pH (2-11), temperature (297,313,333 K), adsorbent dose (0.1-2g), and contact time (0–140 min). The results indicated that the kinetic data for nitrate anion adsorption with MCM-41 was fitted well with the pseudo-second-order kinetic model (R2=1). It was found that the Freundlich adsorption isotherm model for nitrate anion had the best fit with the experimental data. Various adsorbents (activated carbon, SBA-15, MCM-48) have been utilized to investigate their ability to remove nitrate anion and the results show that MCM-48 could be used to remove NO3 better than other adsorbents.