Efficient coagulation and removal of aqueous graphene oxide by different dyes

Abstract

Despite graphene oxide (GO)'s excellent physical and chemical properties, recent researches suggest its toxicity in biological applications. In this study, three dyes, methylene blue (MB), rhodamine-B (RhB) and methyl orange (MO), are used as coagulants to remove GO from aqueous solution. Results show that MB has the best performance with maximum coagulation capacity up to 2.27 g/g, higher than that of most other coagulants. Electrostatic interaction plays a key role in coagulation, also aided by pi-pi stacking interaction. Besides its great coagulation capacity, MB itself is a pollutant abundant in many types of wastewater, providing a readily accessible reagent, which makes it more suitable for the application.