Synthesis of reduced graphene oxide using agro waste
Graphene oxide (GO) and reduced graphene oxide (rGO) have great potential to be made into membranes for water purification purposes. However, the conventional method of synthesizing GO, the Hummer’s method, involves the oxidation of graphite using corrosive chemicals such as concentrated sulfuric acid. Although it is effective, it is extremely expensive and produces toxic gases such as nitrogen dioxide. The subsequent reduction of GO produces rGO.
In this study, reduced graphene oxide (rGO) was synthesized from agro wastes (durian rind and sugarcane bagasse) using an eco-friendly, simple, one-step and low cost process. Agro waste was added to ferrocene and the mixture was oxidized in a furnace under normal atmospheric conditions. Some of its oxygen functional groups were reduced by ferrocene in the furnace to produce rGO. Adsorption studies of the synthesized rGO was carried out with methylene blue and copper(II) ion.
Results showed that rGO was successfully synthesized from durian rind. In contrast, sugarcane bagasse resulted in the formation of a mixture of both GO and rGO. rGO from durian rind was comparable to commercial activated carbon in removing methylene blue. More importantly, because it contains more oxygen functional groups than commercial activated carbon, it is 32% more effective than commercial activated carbon in adsorbing copper(II) ions.
When coated onto MCE filter papers, rGO filter was able to remove 97% methylene blue and close to 100% of copper(II) ions. When packed into a column, rGO was able to remove almost 100% of both methylene and copper(II) ions across 6 cycles of filtration. rGO synthesized from durian rind has great potential to be incorporated into filters and be used to remove organic dyes and metal ions from polluted water.