Synthesis of Mg(OH)2@Reduced graphene oxide nanocomposite andapplication for simultaneous micro solid phase extraction of uranium andthorium using micropipette tip syringe system

Recently, nanoscale magnesium hydroxide (Mg(OH)2) has aroused widespread attentionbecause of low-cost, environmental friendly, recyclable, large specific surface area, andextraction ability. It has been shown that Mg(OH)2 exhibits a hopeful prospect in removal ofheavy metals, acid wastewater treatment, and decoloration of printing and dyeing wastewater[1].Uranium and thorium are vital elements not only in industrial application but also inenvironmental and energy problems. However both of the metal ions are well-known to causeserious toxicological effects in human and their compounds are potential occupationalcarcinogens [2]. Based on the facts, highly selective and sensitive method for determination ofuranium and thorium is blooming.In this work, Mg(OH)2@Reduced graphene oxide nanocomposite was synthesized usinghomogeneous precipitation and then consequent reduction with hydrazine hydrate andrefluxing. This nanocomposite was characterized by using Fourier transform-infraredspectroscopy, X-ray diffraction and transmission electron microscopy. This nanocompositeexhibit good selectivity to uranium and thorium ions and applied for simultaneous micro solidphase extraction (μSPE) of these ions using micropipette tip syringe system. The effectiveparameters on μSPE were optimized using central composite design. The developed techniquewas applied to the determination of uranium and thorium in environmental water samples withsatisfactory results.