Study on the adsorption capacity and selectivity of magnetic adsorbents based on graphene oxide toward heavy metals

The objective of the thesis was the study of the adsorption capacity of specific adsorbents based on magnetic nanoparticles and graphene oxide nanocomposites. The adsorption process was focused on the removal of selected heavy metal ions: chromium(III), copper(II), and nickel(II), and their mixtures to evidence competitive adsorption and/or selectivity of the sorbents. Mainly magnetite (Fe2O4) nanoparticles were investigated for their easy synthesis and dispersion in water solution. Graphene oxide is an excellent adsorbent material for heavy metal ions and its good dispersibility in aqueous solution makes it easily mixable with the polluted wastewater to be treated. Its good dispersibility during the adsorption phase makes it difficult to separate from the liquid phase. This problem can be overcome, during the recovery phase, by the presence of the magnetic nanoparticles in the composite structure. To study a more effective and separable adsorption system, preliminary tests on the incorporation of the prepared materials in sodium alginate beads have been investigated.