[en] Cotton-cellulose was functionalized using gamma-irradiation-induced grafting of glycidyl methacrylate (GMA) to obtain a hydrophobic cellulose derivative with epoxy groups suitable for further chemical modification. Two grafting techniques were applied. In pre-irradiation grafting (PIG) cellulose was irradiated in air and then immersed in a GMA monomer solution, whereas in simultaneous grafting (SG) cellulose was irradiated in an inert atmosphere in the presence of the monomer. PIG led to a more homogeneous fiber surface, while SG resulted in higher grafting yield but showed clear indications of some GMA-homopolymerization. Effects of the reaction parameters (grafting method, absorbed dose, monomer concentration, solvent composition) were evaluated by SEM, gravimetry (grafting yield) and FTIR spectroscopy. Water uptake of the cellulose decreased while adsorption of a pesticide molecule increased upon grafting. The adsorption was further enhanced by β-cyclodextrin immobilization during SG. This method can be applied to produce adsorbents from cellulose based agricultural wastes. - Highlights: → Fundamentals of two grafting methods for biomass utilization as adsorbents. → Simultaneous grafting is more efficient and useful than the pre-irradiation one. → Methanol/water/surfactant combined solvent gives the best grafting yield. → Grafted cellulose increased hydrophobicity and adsorption of phenolic compounds. → Improved adsorption by bonding β-cyclodextrin during simultaneous grafting.