The aim of the current research is to fabricate chitosan-grafted silica (Chit/SiO2) bionanocomposite for the easy sequestration of anionic dye (Food Green 3) from aqueous solution. The as-prepared nanocomposite material was characterized using powder X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. The adsorption characteristics of Chit/SiO2 nanocomposite were systematically studied as a function of pH, adsorbent dose and initial concentration with respect to contact time. The results revealed that an amount of 0.01 g of Chit/SiO2 showed maximum removal efficacy of the adsorbed dye (30 mg/L) at pH 3. Adsorption equilibrium verified that the experimental statics fitted well with the Langmuir isotherm model with adsorption capacity of 476.19 mg/L. The rate kinetics is well described by pseudo-second-order adsorption model. Moreover, Chit/SiO2 nanocomposite could be successfully regenerated and reused without any major loss in adsorption efficacy. [Figure not available: see fulltext.].