Removal behavior of indigo carmine by Schoenoplectus acutus and Ni nanoscale oxides/Schoenoplectus acutus composite was determined. The characterization of both materials was done by TEM, SEM/EDS, DRX, and BET. Experimental data were best fitted to pseudo second order and Langmuir-Freundlich models for kinetics and isotherm, respectively; these results indicate a chemisorption mechanism on heterogeneous materials. Adsorption capacity of Ni nanoscale oxides/Schoenoplectus acutus composite was high in comparison with other adsorbents (760 mg/g). Adsorption of dye is not affected by pH (3 to 9). Metal nanoparticles supported on cheap and eco-friendly adsorbents are an alternative for the removal of dyes from wastewater.