Graphene oxide cross-linked chitosan nanocomposite adsorbents for the removal of Cr (VI) from aqueous environments

A graphene oxide-chitosan composite (GO-CS) adsorbent was synthesized, in which GO played a cross-linking role. The synthesized GO-CS had good acid-resistance and mechanical strength, which was attributed to excellent cross-linking. The GO-OS was evaluated as an adsorbent for the removal of Cr(VI) from aqueous solutions. Experimental results confirmed that GO-CS has an excellent adsorption capacity for Cr(VI) (similar to 67.8 mg/g). Kinetic regression results showed that the adsorption kinetics were more accurately represented by a pseudo second-order model. The overall adsorption process was jointly controlled by external mass transfer and intra-particle diffusion, whereby intra-particle diffusion played a dominant role. The Langmuir isotherm model provided a good fit for the adsorption process. The remarkable adsorption capacity of the GO-CS for Cr(VI) can be attributed to the combined adsorption interaction mechanisms onto the GO-CS. The results of this work are significant for environmental applications of GO-CS as a promising adsorbent for the removal of heavy metal pollutants from aqueous solutions.