Chitosan/Graphene Oxide/Nanocellulose Composites for Removal of Cu(II) and Pb(II) Ions in Aqueous Solution

In this study, graphene oxide (GO) and nanocellulose (CN) additives were used in chitosan polymer matrix to prepare composites by solution casting method. The influence of particles on mechanical and thermal properties of chitosan based composites were investigated by using thermogravimetric analysis, and tensile tests, respectively. The prepared composites were characterized in terms of morphology, chemical structure, wettability and adsorption properties for heavy-metal ions (Cu(II) and Pb(II)) in aqueous solutions. The study revealed that graphene oxide synthesized by Hummers method was homogeneously distributed in chitosan and the tensile properties of the as-prepared composites were improved significantly over that of the neat chitosan (C) film. However, addition of nanocellulose particles resulted in a decline of tensile properties of chitosan/graphene oxide composites. The decrease in tensile strength and modulus is most probably ascribed to the poor dispersion of particles in the matrix and poor filler-filler (CN-GO) interactions.Heavy metal removal of composites was analyzed by using ICP-OES. It was proved that GO addition led to an increment of the adsorption of Cu(II) and Pb(II) ions compared to neat chitosan. Addition of CN into chitosan/GO films did not noticeably affect the removal of heavy metal ions. On the other hand, the significant effect of nanocellulose addition was observed in thermal stability and wettability of chitosan/GO composites. These biodegradable, nontoxic composite films have a potential to use as membranes for metal ions in aqueous solution.