Yuanzhe Gao

Synthesis of MnFe2O4@Mn–Co oxide core–shell nanoparticles and their excellent performance for heavy metal removal

Magnetic nanomaterials that can be easily separated and recycled due to their magnetic properties have received considerable attention in the field of water treatment. However, these nanomaterials usually tend to aggregate and alter their properties. Herein, we report an economical and environmentally friendly method for the synthesis of magnetic nanoparticles with core-shell structure. MnFe2O4 nanoparticles have been successfully coated with amorphous Mn-Co oxide shells. The synthesized MnFe2O4@Mn-Co oxide nanoparticles have highly negatively charged surface in aqueous solution over a wide pH range, thus preventing their aggregation and enhancing their performance for heavy metal cation removal. The adsorption isotherms are well fitted to a Langmuir adsorption model, and the maximal adsorption capacities of Pb(II), Cu(II) and Cd(II) on MnFe2O4@Mn-Co oxide are 481.2, 386.2 and 345.5 mg g(-1), respectively. All the metal ions can be completely removed from the mixed metal ion solutions in a short time. Desorption studies confirm that the adsorbent can be effectively regenerated and reused.

Fabrication of magnetic core–shell nanocomposites with superior performance for water treatment

Magnetic core–shell nanocomposites were synthesized by an economical and environmentally friendly method. The shell materials with the desired composition can be obtained through simple manipulation of precursor adsorption, which can modify their performance for water treatment. The composite containing appropriate amounts of Fe, Mn, and Co oxides exhibits excellent adsorption capability and catalytic activity for removing heavy metal ions and organic pollutants in water. The results suggest that the chemical modification of the shell material is promising for the optimization of pollutants removal by core–shell nanocomposites.

Novel Doped Tungstovanadate and Molybdovanadate with Bi-antimony-Capped Keggin Structure

Three novel V-centred Keggin-based compounds containing cap-shaped Sb atoms: (HDMF)2[(VO4)W5.65V7.74Sb2.61O36.77]·6H2O (1), [Co(phen)3]2[(VO4)Mo9.58V2.42Sb2O36]·6H2O (2) and [Ni(phen)2(H2O)]2[(VO4)Mo8V4Sb2O36]·2H2O (3) (DMF = dimethylformamide; phen = 1,10-phenanthroline) have been synthesized and characterized. X-ray diffraction analysis revealed that compound 1 consists of an unusually one-dimensional 12-tungstovanadate Keggin-based polymer, in which the reduced tungstovanadate Keggin species are stabilized by introducing capping {VO} and {Sb} groups and then linked into chains via V(Sb)–O–V(Sb) interactions. Both 2 and 3 are built from secondary metal–ligand groups (Co-phen for 2, Ni-phen for 3) and 12-molybdovanadate doped Keggin-type cores with two antimony atoms capping two opposite sites. The anion in 3 represents a bi-capped and bi-supported Keggin-type structure. The electrochemical properties of 2- and 3-modified carbon paste electrodes (2-CPE and 3-CPE) are also studied.

Lignosulfonate-assisted Hydrothermal Synthesis of Mesoporous MnFe2O4 and Fe3O4 for Pb(II) Removal

The development of efficient magnetic adsorbents is highly desirable for water treatment. In this work, MnFe2O4 and Fe3O4 were prepared by a lignosulfonate-assisted hydrothermal method. The structu...