AbstractAmino-functionalized graphene oxide (GO-NH2) was synthesized by grafting (3-aminopropyl) triethoxysilane on the graphene oxide (GO) surface. The GO-NH2 with high surface area and numerous active sites can efficiently adsorb Cr(VI), Cu(II), Pb(II) and Cd(II) ions. The maximum adsorption capacities of GO-NH2 for Cr(VI), Cu(II), Pb(II) and Cd(II) were 280.11, 26.25, 71.89 and 10.04 mg g−1, respectively. The pseudo-first-order and pseudo-second-order kinetic models were employed to describe the kinetic processes. The experimental data agreed well with the pseudo-second-order kinetic equation, and the adsorption of heavy metals onto GO-NH2 occurs via chemical adsorption. The characteristics of Cr(VI), Cu(II), Pb(II) and Cd(II) in the GO-NH2 adsorption processes were analyzed using the Langmuir and Freundlich isotherm models. The adsorption processes of Pb(II) and Cd(II) on GO-NH2 were fit by the Langmuir model. The Freundlich isotherm model was well correlated to Cr(VI) and Cu(II). The GO-NH2 is a promising material for the removal of heavy metal ions from industrial wastewater. This study provides an effective pathway to process industrial wastewater, and the GO-NH2 has a good adsorption effect for the treatment of heavy metals in industrial wastewater.

Molybdenum disulfide (MoS) was used as an electrically conductive skeleton and functionalized with an ionic liquid and gold/silver nanorods. The resulting composite was characterized by scanning electron microscopy, transmission electron microscopy and UV-vis spectroscopy. The composites were used to modify a glassy carbon electrode (GCE) to obtain a sensor for 2,4-dichlorophenol (2,4-DCP). The results show that the oxidation power and electrocatalytic activity of the modified GCE towards 2,4-DCP are enhanced compared to a bare GCE and other modified GCEs. Response is linear in the 0.01 to 50 μM 2,4-DCP concentration range, with a 2.6 nM detection limit. The sensor is highly sensitive and long-term stable. It was successfully applied to the determination of 2,4-DCP in spiked water samples and gave satisfactory recoveries. Graphical abstract Schematic of an electrochemical sensor for the differential pulse voltammetric (DPV) determination of 2,4-dichlorophenol. It is based on the use of an MoS-ionic liquid-Au/Ag nanorod composite.

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