News revealed that Hong Kong drinkable water with lead ion tainted in 2015 and the source of pollution is the pipeline used for transporting drinkable water from water supplies department to household. The common technique to eliminate heavy metal ions include but not limited to adsorption, membrane separation, precipitation, ion exchange and solvent extraction[1]. Ding[2] has proposed to use graphene oxide membrane being a layer structure in a fixed bed sand column to filter out heavy metal ions, such as copper and lead. The result of this design showed the removal of lead ions up to 40.5%. This shows the potential of graphene oxide on binding heavy metal ions in solution. Adsorption of heavy metal ion by graphene oxide has an outweigh advantage than graphene oxide membrane as it can be cleaned easily with ethanol and water and, more importantly, the concern on flux can be ignored as recent membrane used for filtering heavy metal ions are having problems on low permeability and flux[3].

Hypermark GO [4] has review that graphene oxide, compared to clay and activated carbon, could hold up lead per gram with twenty times high and thus less solid waste generated but there is concern on removing the lead bound graphene oxide as the structure of the graphene oxide in the form was not big enough and with size ten times than that of clay particles. Therefore, the company predicts that using graphene oxide to be an absorbent still needs a long way to achieve.

In this paper, GO-PMMA solid fabricated from marking the GO-PMMA solution in section 3.4 was used to test its ability on absorbing the lead ion obtained from standard solution. PMMA solid with same mass as the GO-PMMA solid would be used for the control setup. 5 samples of the test solution were collected at 0 min, 10 min, 30 min, 50 min and 70 min. The results show that GO-PMMA solid has a rough surface and through hole structure and has an ability on absorbing lead ion up to 68.6%, which is 65.8% higher than the control setup, at room temperature and pressure. The dry mass of GO-PMMA solid is around 119.82g and the mass after testing is around 124.21g. The ability of absorption can be easily refreshed by washing with ethanol and distillated water (80/20 v/v) several times. The experiment would explore a new page for graphene oxide applied on heavy metal ion removal. It is anticipated that the GO-PMMA solid could also be a new starting point for seawater desalination and blood purification.