© 2020 Elsevier B.V. Cellulose/clay composites were prepared and applied for the adsorption of Drimarine Yellow HF-3GL direct dye. The prepared composites were characterized by FTIR, TGA, EDX, SEM and XRD techniques. Bagasse was used as a cellulose source, while clay was obtained from local source, which was modified chemically before composite preparation. Adsorption efficiencies were compared of composite I and II as a function of contact time, temperature, pH, initial dye concentration and composite dose. Non-linear kinetic and equilibrium isotherm employed and dye adsorption data fitted well to pseudo-second order kinetics model. Among isotherms, the Redlich-Peterson isotherm well defined the sorption process of dye on to composites. Thermodynamic factors (ΔS°, ΔH° and ΔG°) revealed that the sorption process was spontaneous, exothermic and feasible. Cellulose/clay composite I and II removed 88.64% and 89.95% dye with 60 min at pH 2 and 30 °C, respectively. For reusability, desorption was performed using different eluting agents and NaOH showed higher desorption efficiency. For the treatment of wastewater, the developed composites were applied to textile effluents and color removal of (90–96.07%) and (97–98.23%) was achieved using cellulose/clay composite I and II, respectively. The results showed that cellulose/clay composite are efficient for the removal dyes and could possibly be used for the treatment of textile effluents.