In this paper, silica nanoparticle (SN) and amine-functionalized silica nanoparticle (AFSN) were prepared and their dye removal abilities were investigated. Physical characteristics of adsorbents were studied using the point of zero charge, surface area, Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Three textile dyes, Acid Red 14 (AR14), Acid Black 1 (AB1) and Acid Blue 25 (AB25), were used as model compounds. The effect of operational parameter such as adsorbent dosage, pH, dye concentration and salt were evaluated. The isotherm and kinetic of dye adsorption were studied. The maximum dye adsorption capacity (Q(0)) of SN for AR14, AB1 and AB25 was 0.031 mg/g, 0.034 mg/g and 0.170 mg/g, respectively. But the maximum dye adsorption capacity of AFSN for AR14, AB1 and AB25 was 434 mg/g, 250 mg/g and 167 mg/g, respectively. It was found that dye adsorption onto SN and AFSN followed with Freundlich and Langmuir isotherms, respectively. Adsorption kinetic of dyes was found to conform to pseudo-second order kinetics. Based on the data of present investigation, one could conclude that the AFSN being an eco-friendly adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored aqueous solutions. (C) 2011 Elsevier B.V. All rights reserved.