In the present work, a novel biodegradable nanocomposite has been developed (h-GG/SiO2) based on anionically modified guar gum and in-situ deposited SiO2 NPs through sol-gel technique. Here the anionically modified guar gum stimulates the silica polymerization process and hence acts as a unique template for the development of spherical SiO2 NPs. Batch adsorption studies indicate that h-GG/SiO2 nanocomposite shows remarkable adsorption capacity for cationic dyes/metal ions (Q(max): 781.25 mg g(-1) for malachite green (MG), 281.69 mg g(-1) for safranin (SF); 645.16 mg g(-1) for Pb2+, 709.21 mg g(-1) for Cd2+) as well as it efficiently and selectively removes cationic MG from mixture of dye solutions. Finally the worthy regenerative efficacy of h-GG/SiO2 facilitates the adsorbent to be economically promising for practical application in the field of wastewater management. (C) 2016 Elsevier Ltd. All rights reserved.