This study presents the sustainable applications of recycling agricultural waste. The cellulose from sugarcane bagasse (SCB) was extracted to prepare the carboxymethyl cellulose (CMC) used as the starting material for synthesizing CMC‐based hydrogel for the selective adsorption of Cu(II) ions in contaminated solution. Hydrogel fabrication was performed under microwave‐assisted irradiation, which helps to improve reaction efficiency and significantly reduces reaction time compared with using a conventional hotplate. The hydrogel of 25% CMC blended with poly(vinyl alcohol) (PVA) and using glutaraldehyde (GA) as a cross‐linking agent showed the property of selective adsorption for Cu(II) ions from the solution with an adsorption capacity of 2.3 mg/g (92.4% removal) under ambient temperature with pH 5.0. The adsorbed Cu(II) ions were effectively desorbed from the hydrogel by either 0.1 M HCl or 0.1 M EDTA. Thus, the prepared hydrogel could potentially be applied in the removal of Cu(II) ions from contaminated water, with promising potential for reuse after the regeneration process. Sugarcane bagasse was used as a starting material for the synthesis of hydrogel, which has selective adsorption property to Cu(II) ions. In addition, microwave‐assisted irradiation, technology that is able to save time and energy, was exploited for the polymer synthesis. Therefore, this study presents the sustainable applications of recycling agricultural waste for the purpose of water treatment. © 2018 American Institute of Chemical Engineers Environ Prog, 38: S157–S165, 2019