Tannic acid adsorption on amino-functionalized magnetic mesoporous silica

Amino-functionalized magnetic mesoporous silica (magMCM-41-NH2) was prepared and adsorption of organic pollutant tannic acid (TA) from aqueous solution on the resulting material was investigated The adsorbent was characterized by elemental analysis X-ray diffraction (XRD) transmission electron microscopy (TEM) N-2 adsorption-desorption IR spectroscopy Zeta potential measurements and vibration sample magnetometer (VSM) Characterization results showed that magMCM-41-NH2 had ordered mesoporous structure with amino group content of 457 wt% BET surface area of 668 m(2)/g and the pore volume of 0 525 cm(3)/g Batch adsorption tests indicated that magMCM-41-NH2 adsorbent exhibited high adsorption affinity towards aqueous TA with a maximum adsorption capacity of 510 2 mg/g The Freundlich model could fit the adsorption isotherm of TA over magMCM-41-NH2 very well implying that adsorption process is heterogeneous TA adsorption on magMCM-41-NH2 could be well described by the pseudo-second-order kinetics Adsorption of TA on the adsorbent was found to be strongly dependent on pH and Ionic strength suggesting that electrostatic interaction played a crucial role in TA adsorption Xray photoelectron spectroscopy (XPS) analysis confirmed the formation of complex compound between TA and surface amino groups of magMCM-41-NH2 upon adsorption (C) 2010 Elsevier B V All rights reserved