Electroconductive membranes have a wide variety of applications in water treatment such as: electrostatic rejection of charged molecules; self-cleaning through electrochemical oxidation of organic contaminants, and selectivity modification under potential bias. To be useful in such applications, the membrane should be inexpensive, highly conductive, flexible, durable, and stable under applied potentials Typical methods of conductive membrane production include: blending active material into the membrane, binding active material to membrane surface, or using conductive polymer. Each method has downfalls, such as: high active material loading and low activity (blending), complicated fabrication and low durability (binding), and expensive material with low durability (conductive polymer). We have developed a membrane which aims to overcome these shortfalls. Our method of membrane fabrication integrates graphene into the membrane during phase inversion. In the formed structure, graphene only exists within 1 µm of the membrane surface, providing a porous electrochemically active surface supported by a nonconductive layer. This membrane has high surface conductivity, and the surface is durable due to physical integration of polymer during phase inversion. This membrane displays gas and water permeability and has good mechanical properties. It retains conductivity when stretched until fracture at 9.5%. Ultraviolet light (UV) can create pores in graphene through oxidative etching. We demonstrate the ability to increase permeance through UV induced poration of the membrane’s graphene surface. Using cyclic voltammetry, we show increased capacitance and electrochemical activity due to UV poration. We report the impact of UV poration on salt selectivity. Also, we demonstrate different polymers can be used in membrane formation and the membrane structure can be modified with pore forming additives. Lastly, we investigate how permselectivity is modified under application of electrical potential.

Highly conductive, low-cost, and durable graphene composite membrane with multi-purpose application

2019 Fall National Meeting

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