Mesoporous silica nanoparticle-decorated graphene oxide nanosheets (MSiO2-GO) were synthesized and characterized for the active removal of lead (Pb2+) from the water. MSiO2 NPs were prepared via an ultrasonication method using tetraethyl orthosilicate (TEOS), and GO sheets were obtained via a modified Hummers' method. X-ray diffraction, UV-vis spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive X-ray spectroscopy specified the composition of MSiO2 NPs and GO sheets. The surface charge and texture of the MSiO2-GO nanosheets were obtained using the ζ-potential technique and by field emission scanning electron microscopy. The relative cytotoxicity test of MSiO2 NPs and MSiO2-GO nanosheets was performed on Murine Raw 264.7 cells before implying the treatment of water. Adsorption of Pb2+ ions on MSiO2-GO nanosheets was examined at various parameters such as different aqueous pH values (2.0-10.0), MSiO2-GO nanosheet doses (3, 5, 10, 15, 20 mg L-1), time intervals (2-30 min), and temperatures (25-45 °C). About 90% of Pb2+ ions were removed from water within 30 min (MSiO2-GO dose: 15 mg L-1; initial Pb2+ ions: 50 mg L-1; temperature: 25 °C; shaking speed: 200 rpm). The maximal uptake of Pb2+ was obtained at solution pH 6.0. Pseudo-first- and pseudo-second-order kinetic rate equations describe the sorption dynamic data. Pb2+ sorption isotherms were modeled using the Freundlich and Langmuir isotherm models. The possible mechanism of binding of Pb2+ ions onto MSiO2-GO nanosheets has been discussed. The exhausted MSiO2-GO nanosheets were successfully regenerated using 0.005 M HNO3 as the desorbing agent.
© 2023 The Authors. Published by American Chemical Society.