adsorbent. The effect of NA concentration on the adsorption of NA from an aqueous solution by HSANGs was studied kinetically at different concentrations (5.0, 25.0, and 50.0 mg L1results are presented in Fig. 7. Generally, increasing the NA concentration leads to the reduction in the amount of NA adsorbed on HSANGs due to the lack of the adsorption binding sites available) and the for the NA molecules.