Removal of chlorine and monochloramine from tap water using graphene oxide membranes

Abstract

Residual levels of chlorine and monochloramine (chlor(am-)ine) in water not only cause unpleasant odour and taste but also pose a challenge for chlor(am-)ine sensitive applications such as polymeric membranes used in reverse osmosis for desalination. Current solutions to remove chlor(am-)ine have their limitations and it is thus desirable to develop an alternative technology that can remove chlor(am-)ine in a simple filtration process. In this study, we show that graphene oxide (GO) membranes can be used to remove chlor(am-)ine from tap water. The tested feed chlorine and monochloramine concentrations are up to 50 ppm and 9 ppm respectively. For all tested feed concentrations, the permeate chlor(am-)ine concentration is < 0.1 ppm after passing through GO membranes. We show that both flat sheet and hollow fibre GO membranes filter out chlor(am-)ine over days of continuous operation. Especially our hollow fibre GO membranes offer a great opportunity for easy scalability. Thus our study highlights not only the filtration properties of GO membranes but also its feasibility as an excellent contender for next-generation membrane technology.