Magnetic graphene oxide incorporated with Fe2O3 for the removal of lead (II) ions

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).