Reduced graphene oxide modified porous alumina substrate as an electrode material for efficient capacitive deionization

Graphene has received more attention for capacitive deionization (CDI) due to its huge theoretical specific surface area, high electrical conductivity and high salt adsorption capacity. However, the high cost and poor breaking strength have limited its wider development. Herein, we readily prepared a novel electrode material using porous alumina substrate modified by reduced graphene oxide (rGO) in the CDI system, which displayed the superior porous structure, high breaking strength and low cost. Meantime, the effects of the modification times, applied voltage and initial salt concentration on the salt adsorption capacity of the electrode material were studied experimentally. The results demonstrate that the electrode material has a breaking strength up to 40 MPa, displays a remarkable salt adsorption capacity of 5.19 mg/g at 1.2 V in NaCl solution, and has a maximum adsorption capacity of 7.78 mg/g for NaCl. The mechanism of NaCl adsorption was discussed by the isothermal and kinetic experiments. Furthermore, the prepared electrode material exhibited an excellent reusability even after the 50-cycle operation. All these results indicate that the rGO modified porous alumina electrode shows great potential in the field of desalination.