There are many adsorbents available for this purpose: activated carbons, zeolites, ion-exchange resins (IERs), and silica. Silica gels and porous polymers are very popular adsorbents. Other than absorbent different methods are used to remove urea from waste water. Such as methods of urea removal of wastewater streams are electrochemical oxidation, biological treatment, adsorption and hydrolysis using thermal treatment or enzymes and decomposition with the aid of catalyst, strong oxidant. Biological methods of urea removal mainly involve the process scheme in which urea-rich water flows through a series of biofilters. Different strains of bacteria decomposing organic nitrogen to molecular nitrogen are present in these filters.

you can use agriculture waste like (rice husk and sugarcane bagasse) and form activated charcoal.

this activated charcoal can adsorbed urea.

chitosan, CNC & GO based nanocomposites should be much more suitable candidates hrre. You can follow the following paper: https://www.researchgate.net/publication/372689733_Fabrication_of_Nano_Composite_Membrane_Filter_from_Graphene_OxideGO_and_Banana_Rachis_Cellulose_Nano_CrystalCNC_for_Industrial_Effluent_Treatment

https://www.researchgate.net/publication/372689733_Fabrication_of_Nano_Composite_Membrane_Filter_from_Graphene_OxideGO_and_Banana_Rachis_Cellulose_Nano_CrystalCNC_for_Industrial_Effluent_Treatment

https://www.researchgate.net/publication/372689733_Fabrication_of_Nano_Composite_Membrane_Filter_from_Graphene_OxideGO_and_Banana_Rachis_Cellulose_Nano_CrystalCNC_for_Industrial_Effluent_Treatment

Agro base adsorbent in the likes of plantain peel and groundnut pewls when process into activate carbon can be very useful as a good adsorbent

Basir Maleki Biochar can be produced from organic wastes, and it adsorbs urea. You can also produce activated carbon from waste tyres and even from plastic. It also adsorbs urea.

But none of those bind the water molecules, since they are hydrophobic.