Removal of arsenic (V) ions from aqueous solutions by APTMS grafted MCM-48 in batch system

The objective of the present study was arsenic removal from aqueous solutions by MCM-48 mesoporous silica functionalized by 3-Aminopropyl trimethoxysilane (APTMS) in batch system. This sorbent synthesized by sol-gel methods and its structural features were characterized by means of X-ray diffraction, nitrogen adsorption-desorption, thermogravimetric analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. The effects of different independent variables including pH, initial As (V) concentration, sorbent dosage, contact time and temperature in adsorption were studied. The obtained results revealed that MCM-48 particles size exhibited from 400 to 500 nm with spherical morphology having a pore size about 2.44 nm, specific surface areas 1326 m2.g-1 and total pores volume were 1.11 cm3.g-1. The results of the As(V) adsorption by NH2-MCM-48 revealed that the optimum values for pH, initial As(V) concentration and sorbent dosage were found to be 2, 50 mg.L-1 and 1 g.L-1, respectively. In addition, Thermodynamic study indicated the endothermic behavior and spontaneous nature of adsorption. The study of the kinetics also showed that data from the experiments fitted well to pseudo-second order equation. On the other hand, Langmuir model better fitted with the experimental data among the two adsorption isotherm models used.