Arsenic removal by means of quaternary ammonium-based cross-linked polymer nanocomposites and titanium oxide nanoparticles as filler is presented. Firstly, the TiO2 nanoparticles were functionalized using the organosilane reagent 3-methacryloxypropyltrimethoxysilane. Subsequently, the modified nanoparticles were incorporated into a polymer matrix by in situ polymerization of a mixture containing monomer, cross-linking, nanoparticles and initiator reagents. Diverse characterization techniques were used at the different stages of the synthesis, namely, infrared spectroscopy (FT-IR), electron microscopy (TEM-SEM), X-ray diffraction (DRX), solid-state C-13 nuclear magnetic resonance (NMR), and thermogravimetric analysis (TGA). The results confirmed the presence of nanoparticles both on the inside of the polymer and on the surface nanocomposite particles. Sorption experiments were conducted as a function of the pH, concentration, time, and nanoparticles loading. The results indicate that TiO2 enhanced the sorption at acidic pH and increase the sorption. In general, the kinetics was notably fast, the process was exothermic and the sorption capacity was approximately 150 mg As g(-1) determined by Langmuir isotherm. (C) 2015 Elsevier B.V. All rights reserved.