Rapid and efficient removal of ionic impurities from graphene oxide through hollow fiber diafiltration

Abstract

Graphene has tremendous importance due to its potential applications in electronics, catalysis, sensors, etc. On the other hand, graphene oxide (GO) or reduced graphene oxide (rGO) have increasing applications in various fields such as water treatment, catalysis, etc. Major bottleneck of large scale production is purification of GO and it is traditionally conducted in time consuming dialysis in small batches. The present work demonstrates utility and applicability of continuous hollow fiber diafiltration for the removal of ionic impurities from GO solution. 12 kDa cut off hollow fibers demonstrated the best results. Seven stages with 250 ml constant volume of diafiltration and five hours of filtration at 103 kPa transmembrane pressure drop and 10 L/h cross flow rate were found to be suitable conditions of purification. Produced GO had quality comparable to the commercial ones. Thus, continuous diafiltration was found to be an efficient and highly scalable GO purification technique.