Magnetic graphene oxide incorporated with Fe2O3 for the removal of lead (II) ions / Norhusna Mohamad Nor ... [et al.]

The objective of this research work is to synthesise graphene oxide (GO) with iron oxide (Fe2O3) nanoparticles as a magnetic adsorbent for lead ion (Pb2+) removal. In this work, the effect of synthesis parameters of GO/Fe2O3 (Fe2O3 loading weight ratio, synthesis time and calcination temperature) and adsorption parameters (initial Pb2+ concentration, adsorption temperature and contact time) on Pb2+ removal were investigated. The adsorption experiment was carried out in a batch system, and the synthesised GO/Fe2O3 adsorbent was characterised using TGA and N2 sorption-desorption analyses. The adsorption characteristics of Pb2+ using GO/Fe2O3 adsorbent were analysed using adsorption isotherms and kinetic study. The optimal synthesis parameters were found to be a 1:0.5 ratio for GO/Fe2O3, a synthesis time of 60 min and a calcination temperature of 400°C, resulting in a Pb2+ removal rate of 96% and adsorption capacity of 49.85 mg Pb2+/g adsorbent. The GO/Fe2O3 adsorbent synthesised at 400°C and a 1:0.5 ratio exhibits a larger surface area and smaller pore diameter, 98.20 m2/g and 15.67 nm, respectively, compared to other samples. Increasing the synthesis temperature decreases the growth and formation of GO/Fe2O3, reducing the surface area. Experimental results revealed that the adsorption of Pb2+ using GO/Fe2O3 adsorbent fitted the pseudo-second-order kinetic and was best described by the Langmuir isotherm with a high correlation coefficient (R2 >0.99).