Synthesis, amine functionalization and dye removal ability of titania/silica nano-hybrid

In this paper, titania/silica nano-hybrid (TSNH) and amine-functionalized titania/silica nano-hybrid (AFTSNH) (LAFTSNH: low amine-functionalized titania/silica nano-hybrid and HAFTSNH: high amine-functionalized titania/silica nano-hybrid) were synthesized and their dye removal abilities were investigated. Physical characteristics of adsorbents were studied using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Reactive Red 198 (RR198) and Acid Red 14 (AR14) were used as model compounds. The kinetic and isotherm of dye adsorption were studied. The effects of operational parameters such as adsorbent dosage, initial dye concentration, pH and salt on dye removal were evaluated. Adsorption kinetic of dyes was found to conform to pseudo-second order kinetics. The maximum dye adsorption capacity (Q(0)) of TSNH, LAFTSNH and HAFTSNH were 0.027, 116.279 and 138.889 mg/g for RR198 and 0.232, 270.270 and 315.500 mg/g for AR14, respectively. Dye adsorption onto TSNH, LAFTSNH and HAFTSNH for both dyes followed with Langmuir. Freundlich and Langmuir isotherms, respectively. The results showed that the AFTSNH as an adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored wastewater. (C) 2012 Elsevier Inc. All rights reserved.