Oscillating electric field assisted nano-incised graphene kirigami for ultrahigh-performance water desalination membrane

Benefiting from the single-atom thickness, dense honeycomb structure, nano-size pores, and adjustable selection capability, graphene kirigami (GK) is expected to be a promising candidate for the membrane of water desalination. However, due to the low bending stiffness of the GK structure, the fluctuation in incision size and the accumulation of salt ions around the incisions always limit the GK membrane from higher water desalination efficiency. In this study, we adopted an oscillating electric field to improve the water desalination efficiency of nano-incised GK via molecular dynamic (MD) simulation. The results reveal that with the oscillating electric field's assistance, the water permeability of the GK membrane achieves 1351.6 L/m2/h/bar theoretically under the condition of 100 % salt rejection, 5.9-7.1 times higher than the reported nano-porous graphene membrane and 2-5 orders of magnitude higher than the existing reverse osmosis membranes. The oscillating electric field can enhance the water desalination efficiency of the proposed GK membranes mainly by alleviating the structural fluctuation of the GK membrane and dredging the permeation pathway for water molecules. The considerable potential of the oscillating electric field-assisted GK membrane reported by this study will attract great attention in the field of water separation and purification.

Automated summary

Graphene kirigami (GK) is a promising candidate for water desalination membrane due to its unique structure and excellent properties. However, the low bending stiffness and fluctuation in incision size of GK structure limit its water desalination efficiency. In this study, an oscillating electric field was used to improve the water desalination efficiency of nano-incised GK membranes through molecular dynamic simulation. The results showed that the water permeability of GK membranes can be significantly increased with the assistance of the oscillating electric field, indicating its considerable potential in the field of water separation and purification.