Wei Gu

In this work, graphene oxide/Fe3O4 (GO/Fe3O4) composites were synthesized via a copper catalyzed azide-alkyne cycloaddition reaction for the first time. After further modification with polyacrylic acid (PAA), water-soluble magnetic graphene nanocomposites were obtained. The PAA/GO/Fe3O4nanocomposites were characterized by atomic force microscopy, transmission electron microscopy, X-ray diffraction, Raman, Fourier transform infrared spectroscopy, thermogravimetric analysis and vibrating sample magnetometry. Due to the high surface area, excellent complex ability and superparamagnetism, the PAA/GO/Fe3O4 nanocomposites were used as nanoadsorbents for recyclable removal of Cu2+, Cd2+ and Pb2+ ions from aqueous solution. It is found that the PAA/GO/Fe3O4 nanocomposites show extraordinary removal capacity for Cu2+, Cd2+ and Pb2+ ions. Moreover, the PAA/GO/Fe3O4 nanocomposites are very easy to separate and recycle due to the superparamagnetism of Fe3O4. After five cycles, the removal efficacy of the nanoadsorbents for Cu2+, Cd2+ and Pb2+ ions is over 85%. All of the results demonstrate that the water-soluble magnetic graphene composites are effective adsorbents for removal of heavy metals and thus could provide a new platform for water cleanup.

In this work, different thermal aggregation behaviors of soy β-conglycinin and glycinin at pH 7.0 were characterized with size exclusion chromatography and low-angle light scattering. Limited aggregation that grew via the consumption of "monomers" was detected in β-conglycinin, forming soluble aggregates. For glycinin, the association between the aggregates that led to the appearance of insoluble materials was observed. Heated with β-conglycinin, the assembly between the glycinin aggregates was terminated and its solubility was recovered. The structure of the soluble and insoluble aggregates was analyzed by small-angle X-ray scattering and dynamic light scattering. Unlike the β-conglycinin soluble aggregates that possessed limited size and less compact conformation, particles with a denser core and a less dense outer shell were found in the glycinin insoluble aggregates. Evidence is presented to reveal the transition between the soluble and insoluble aggregates and the role of β-conglycinin in the solubilization of the soy protein aggregates during heating.