Hydrogel nanocomposites (HNCs) of carboxymethyl cellulose (CMC) and poly(acrylic acid-co-2-acrylamido-2-methylpropane sulfonic acid) were prepared via in situ cross-linking copolymerization method followed by incorporation of cadmium sulfide quantum dots (CdS-QDs) within the network. The structure and surface morphology of the prepared HNCs were fully characterized using FTIR, SEM, EDX, XRD, TGA/DTG, UV–Vis, TEM and DLS techniques along with fluorescent microscopy.The influence of Na2S, CdCl2, and monomers concentrations onto swelling capacity of HNCs were optimized and a maximum swelling of 154g/g was determined. Moreover, the HNC was employed for the adsorption of cationic dye, Rhodamine B (RhB), from aqueous solution. The impacts of experimental variables on the removal of RhB were explored. The adsorption process was followed the pseudo-second-order kinetic model and the experimental data also fitted well with the Langmuir isotherm model with a maximum RhB adsorption capacity of 137mg/g. Conclusively, the HNCs could be used as an efficient adsorbent for the removal of RhB dye from contaminated water.