Experimental investigation of the manufacture of tunable graphene oxide filter membranes using intense pulse light

Abstract

Reduced graphene oxide is a thin, strong, and inexpensive material with a channel and pore structure that make it a promising candidate for a filtration material. Reduced graphene oxide has been produced and tested in the laboratory, but a lack of scalable manufacturing techniques have limited its commercial use. This thesis has shown that graphene oxide can be rapidly manufactured with an industrially scalable flash reduction process. The flash reduction process uses 0.58 millisecond pulses from a xenon lamp to reduce the graphene oxide film in less than a minute. Results for partially reduced graphene oxide membranes tuned by the length of exposure have variable filtration flux and filtrate rejection rates. Graphene oxide films were found to reject 20% to 90% of a methyl-red dye solution, depending on their reduction level. Finally, the color of graphene oxide films was correlated to their reduction level using digital photography. Graphene oxide films were exposed to 10, 40, 70, and 100 light pulses with xenon lamp powers of 1.8 kV, 2.0 kV, and 2.2 kV. The colors of the resulting films were determined by the amount of energy the films had received. The experimental methods used to obtain these results include vacuum filtration of graphene oxide monolayer dispersions, flash reduction of the resulting films, and pressurized filtration testing. The experimental results were characterized by atomic force microscopy, scanning electron microscopy, digital color measurement, and ultraviolet and visible light spectrophotometry.