Nanocomposites of functionalized Metal−Organic frameworks and magnetic graphene oxide for selective adsorption and efficient determination of Lead(II)

Abstract

A novel nanocomposite of functionalized Metal−Organic frameworks and magnetic graphene oxide (Fe3O4@C-GO-MOF) was successfully synthesized as a new magnetic solid-phase extraction (MSPE) adsorbent for selective adsorption and efficient determination of lead ions at trace level. The prepared Fe3O4@C-GO-MOF nanocomposite possessed high surface area and sufficient porosity. The nanocomposite was magnetic and could be facilely separated from the solution by an external magnetic field. The hybrid nanocomposite showed remarkable maximum adsorption capacity and was estimated as 344.83 ​mg/g. The adsorption parameters including the solution pH, the adsorbent amount and the adsorption time were optimized by batch adsorption experiments. The adsorption kinetics, isotherm and adsorption mechanism were also discussed in detail. The prepared composite selectively adsorbed Pb(II) from the mixed solution of multiple coexisting ions and had good recovery performance after five adsorption-desorption cycles. Under the optimized experimental conditions, a new MSPE method was established with good linearity, low detection limit and great reproducibility for the determination of Pb(II). The selectivity extraction of Pb(II) in different environmental samples showed satisfactory recoveries. The results show that the Fe3O4@C-GO-MOF nanocomposite is a promising candidate for sample pretreatment and preconcentration in the detection of lead ions.