This manuscript illustrates the feasibility of polyacrylamide grafted xanthan gum/silica based nanocomposite toward its potential application as high performance flocculant for treatment of synthetic effluents and mine wastewater. The flocculation performance of the nanocomposite was systematically evaluated by floc size measurement as well as by traditional turbidity and settling velocity measurement. The flocculation kinetics is in good agreement with the aggregation of particle and particle collision model simultaneously. Furthermore, the effect of flocculant dosage on the synthetic effluent (kaolin and iron-ore suspensions) suggests that the bridging flocculation mechanism is predominating here. The graft copolymer-based nanocomposite also possesses a comprehensive color removal ability from mine wastewater.