AbstractLow‐cost‐effective applied technologies for water and wastewater treatment, such as microalgae, have growing attention due to their mutual benefit in wastewater treatment and for valuable algae biomass production. A newly constructed Nile water algae cross‐linked cellulose microsphere (NACS) was applied by functionalization of cross‐linked cellulose acetate with dry Nile water algae forming an efficient adsorptive microsphere. The adsorption capacity of microspheres was evaluated for the removal of basic dye (Methylene blue: MB) and heavy metal copper ions (Cu+2). The molecular structure revealed that the prepared microspheres have several functional groups and elements that have a high affinity for heavy metals and dye removal; furthermore, the morphological structure emphasizes this removal affinity by the presence of micropores at the surface of the microsphere. The results of maximum biosorption conditions showed both MB and Cu through the microsphere were 20 mg/L MB and (10 and 20) mg/L Cu concentrations, 2 g/L of adsorbent dose, pH (MB = 6 and Cu = 5.5), and contact time of 60 min. The maximum adsorption capacities (qmax) were significantly enhanced at 200 and 153.2 mg/g for MB and Cu (II), respectively. The possibility of removal, recovery, and reuse of MB by prepared microsphere was efficiently achieved.