*3.5. SEM*

Microscopic images of RGO, gum tragacanth-cl-*N,N*-dimethylacrylamide hydrogel and reduced graphene oxide incorporated gum tragacanth-cl-*N,N*-dimethylacrylamide hydrogel composite are shown in Figure 4. In RGO, Figure 4a shows the aggregated wrinkled structure, which means particles were closely associated. The RGO morphology showed the formation of agglomerated RGO with estimated average grain size of 20–25 nm. Figure 4b shows the distribution of certain bulges on a quite smooth, porous and compact surface of gum tragacanth-cl-*N,N*-dimethylacrylamide hydrogel. After the incorporation of RGO, reduced graphene oxide incorporated gum tragacanth-cl-*N,N*-dimethylacrylamide hydrogel composite showed (Figure 4c) the rough and irregular surface with reduced size which was beneficial in fast adsorption of Hg2<sup>+</sup> and Cr6+.
