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Iron sulfide (FeS) nanoparticles were known for their excellent ability to scavenge aqueous Hg(II). However, the aggregation and oxidizability of FeS nanoparticles greatly restricted their practical application. This study developed an Al 2 O 3 -supported nanoscale FeS (FeS/Al 2 O 3 ) which effectively optimized the material performance. Characteristic data suggested that FeS/Al 2 O 3 (mass ratio of FeS to FeS/Al 2 O 3 is 30%) with a large specific surface area (142.7 m 2 g −1 ) could evenly distribute FeS, suppressing the aggregation of FeS successfully. The maximum enrichment capacity of Hg(II) on FeS/Al 2 O 3 achieved ∼313 mg/g at pH 6 and 30 °C. The pH studies indicated that alkaline environment strongly inhibited mercury uptake, while removal rate of 1 mg/L Hg(II) maintained a high level (>97.5%) over the pH range of 3–9. However, FeS/Al 2 O 3 loss was observed at low pH due to the acid corrosion. Additionally, the rates of Hg(II) reduction were almost unaffected over the range of 0.1–100 mM NaCl, but greatly inhibited by the presence of humid acid (HA). The synthetic FeS/Al 2 O 3 remained high mercury removal efficiency (over 95% in 1 mg/L Hg(II)) and low iron dissolution rate when preserved for 30 days, showing good long-term stability and remarkable application potential. [ABSTRACT FROM AUTHOR]

Multilayer Zn-doped SnO 2 nanospheres are successfully synthesized by using Sn/Zn bimetal-organic nanoparticles as precursor. These multilayer spheres are found to be very suitable for solving the critical volume expansion problem and mass transfer property due to its high surface area, small crystal size and hollow structure, which is critical for high capacity metal oxide electrodes for lithium-ion batteries. Moreover, the covalently interconnected three-dimensional graphene foams encapsulated these multilayer spheres are successfully obtained through self-assembly effect and chemical cross-linking of graphene oxide nanosheets. The graphene network could further greatly improve the cycling stability and rate capability of the Zn-doped SnO 2 spheres electrode due to its flexible buffering matrix and high electric conduction. As a result, the graphene encapsulating multilayer Zn-doped SnO 2 spheres anodes exhibit excellent rate capacity and a high reversible capacity of 446 mA h g −1 even after 1000 cycles at the current density of 1 A g −1 . These excellent electrochemical performances are ascribed to its large specific surface area, fast electron/ion transfer, and stable electrode structure. Furthermore, this strategy using covalently interconnected 3D graphene foams encapsulate the Zn-doped SnO 2 spheres not only develops a high performance anode material with long cycle life but also holds great promise for binder-free lithium ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: This study describes the chromium (VI) removal in aqueous solution by nanoscale zero-valent iron (nZVI)-Fe3O4 nanocomposites, which were prepared by a novel in situ reduction method. The effects of several factors, including ionic strength, temperature, co-existing anions and cations and natural organic matters were evaluated. The ionic strength was found to be insignificant to the removal efficiency, while temperature was critical. With the increase in temperature from 10–40°C, 32% removal efficiency increased within 2h from 49.96%. Most anions hindered the reaction, especially in high concentration, such as and , causing a drop of the removal efficiency from 66.48% to 57.47% and 59.93% respectively. In contrast, both cations and moderate natural organic matter facilitated the removal of Cr(VI). It is noteworthy that calcium hardness can greatly promote the reaction, 100% removal efficiency was achieved within 90min and the rate constant k 2 reached 0.528gmg−1 min−1 after adding 40mgL−1 Ca2+, which was ten times more than that in other cases. Possible mechanism was presented, and TEM, SEM and FITR analyses were used to verify these speculations. Hopefully, these results can contribute to a better development of the water treatment facilitates for nZVI-Fe3O4 composites, maintaining its high efficiency in real aqueous environment. [Copyright &y& Elsevier]