Qiu-Ju Xing

Three-Dimensional Reduced Graphene Oxide Coupled with Mn3O4 for Highly Efficient Removal of Sb(III) and Sb(V) from Water

Highly porous, three-dimensional (3D) nanostructured composite adsorbents of reduced graphene oxides/Mn3O4 (RGO/Mn3O4) were fabricated by a facile method of a combination of reflux condensation and solvothermal reactions and systemically characterized. The as-prepared RGO/Mn3O4 possesses a mesoporous 3D structure, in which Mn3O4 nanoparticles are uniformly deposited on the surface of the reduced graphene oxide. The adsorption properties of RGO/Mn3O4 to antimonite (Sb(III)) and antimonate (Sb(V)) were investigated using batch experiments of adsorption isotherms and kinetics. Experimental results show that the RGO/Mn3O4 composite has fast liquid transport and superior adsorption capacity toward antimony (Sb) species in comparison to six recent adsorbents reported in the literature and summarized in a table in this paper. Theoretical maximum adsorption capacities of RGO/Mn3O4 toward Sb(III) and Sb(V) are 151.84 and 105.50 mg/g, respectively, modeled by Langmuir isotherms. The application of RGO/Mn3O4 was demonstrated by using drinking water spiked with Sb (320 μg/L). Fixed-bed column adsorption experiments indicate that the effective breakthrough volumes were 859 and 633 mL bed volumes (BVs) for the Sb(III) and Sb(V), respectively, until the maximum contaminant level of 5 ppb was reached, which is below the maximum limits allowed in drinking water according to the most stringent regulations. The advantages of being nontoxic, highly stable, and resistant to acid and alkali and having high adsorption capacity toward Sb(III) and Sb(V) confirm the great potential application of RGO/Mn3O4 in Sb-spiked water treatment.

A 1-D chain praseodymium complex with chelidamic acid: synthesis, structure, and optical properties

The title compound [Pr(C7H3NO5)(C7H4NO5)(H2O)2] n · 1.25nH2O (1) or [Pr(HChel)(H2Chel)(H2O)2] n · 1.25nH2O, where H3Chel is 4-hydroxypyridine-2,6-dicarboxylic (chelidamic) acid, was synthesized by reaction of chelidamic acid, PrCl3 · 6H2O and H2O under hydrothermal conditions, and characterized by X-ray single-crystal diffraction. The crystal structure of 1 reveals that Pr is nine-coordinate with distorted tricapped trigonal prismatic coordination. Coordination polyhedra are interlinked into a 1-D chain, further linked by hydrogen bonds into a 3-D network. Fluorescence spectra exhibit strong green luminescence with maximum emission at 530 nm when excited with λ ex = 475 nm, originating from π–π* of the ligand.

Controllable synthesis of InTaO4 catalysts of different morphologies using a versatile sol precursor for photocatalytic evolution of H2

For the first time, InTaO4 photocatalysts with different morphologies and structures were facilely prepared using a versatile sol precursor. SEM, TEM and HRTEM were used to characterize their structures and morphologies. The as-synthesized materials exhibit different physicochemical properties. Compared to InTaO4 nanoparticles and SiO2@InTaO4 core–shell nanospheres, InTaO4 nanofibers have higher light absorption ability, larger specific surface area, and better photocatalytic activity for hydrogen evolution. We proposed mechanisms for the formation and photocatalytic activity of the three catalysts. The present work not only provides a new approach for the synthesis of tantalates that are different in morphology and structure but also offers new insights into the controllable preparation of photocatalysts through a versatile precursor for environmental and energy applications.

A New 3D Metal-Organic Framework Containing Chelidamic Acid with Unusual (3,6)-Connected Topology: Synthesis, Crystal Structure, and Optical Properties

A new metal–organic framework [(LaL)·3H2O]n (L = chelidamic acid) with good optical properties was obtained through the hydrothermal reaction. It is the third three-dimensional framework constructed from chelidamic acid and presents a rare (3,6)-connected topology with Schlafli symbol (42.6)2(44.62.87.102).

Syntheses, structures, and optical properties of two cadmium complexes with chelidamic acid

[Cd2(C7H3NO5)2 · 4(H2O)] n · 3nH2O · 0.5n(CH3OH) (1) and [Cd3(C7H2NO5)2 · 10(H2O)] · 2H2O ·0.5CH3OH (2) were synthesized and characterized by X-ray single-crystal diffraction. The crystal structure of 1 reveals that both Cds are seven-coordinate with pentagonal bipyramid geometries. Coordination polyhedra are interlinked into a 1-D chain, further linked by hydrogen bonds into a 3-D network. Complex 2 is a discrete structure, then independent [Cd3(C7H2NO5)2 · 10(H2O)] are linked by hydrogen bonds into a 3-D network. The optical properties of 1 and 2 were investigated with fluorescent spectra; both exhibit strong green luminescence probably originating from π–π* transition of the ligand.

3-D Hydrogen-bonded networks of metal complexes with chelidamic acid and 1,10-phenanthroline: syntheses, structures, and optical properties

The title complexes, (C12H8N2) ⋅ [La(C7H3NO5)(C7H4NO5) ⋅ 3H2O] ⋅ 1.75H2O (1), (C12H8N2) ⋅ [Pr(C7H3NO5)(C7H4NO5) ⋅ 3H2O] ⋅ 2H2O (2), (C12H8N2)[Nd(C7H3NO5)(C7H4NO5) ⋅ 3H2O] ⋅ 2.25H2O (3), and (C12H8N2) ⋅ [Fe(C7H3NO5)(C7H4NO5)] ⋅ 2H2O (4), were synthesized and characterized by single-crystal X-ray diffraction. The crystal structures of 1–3 reveal that they are isomorphous, among which the metal atoms are all nine-coordinate with distorted tricapped trigonal prismatic coordination geometries. The Fe is six-coordinate with a distorted octahedron by two chelidamic acid ligands in 4. Complexes 1–4 are formed into 3-D networks by H-bonds and π–π stacking interactions. The fluorescence spectra of 1–3 were investigated and all exhibit strong luminescence.

Crystal structure of triaqua-(4-hydroxypyridine-2,6-dicarboxylato- N,O,O′)cobalt(II) – ethanol – water (1:0.25:1), Co(H2O)3(C7H3NO5) · 0.25C2H5OH · H2O

C7.50H12.50CoNO9.25, monoclinic, C12/c1 (no. 15), a = 14.596(1) Å, b = 7.0542(5) Å, c = 22.570(2) Å, * = 91.729(1)°, V = 2322.8 Å, Z = 8, Rgt(F) = 0.038, wRref(F ) = 0.151, T = 293 K. Source of material A mixture of cobalt(II) chloride dihydrate (0.25 mmol, 0.042 g), and chelidamic acid (0.25 mmol, 0.05 g,) was dissolved in a 10 ml water. After adding 5 ml ethanol (1 M) to the solution and stirring for about 4 h, the mixture was filtered. The filtrate was allowed to stand at room temperature. Red prismatic-shaped crystals that are stable in air were obtained after 10 d. Elemental analysis — found: C, 27.93 %; H, 3.93 %; N, 4.40 %; calculated for C7.50H12.50CoNO9.25: C, 27.81 %; H, 3.86 %; N, 4.33 %. Experimental details Hydrogen atoms of water molecules were found in difference Fourier map and refined with Uiso(H) = 1.5 Ueq(O). The hydrogen atoms of C2, C4, and O5 were placed in calculated positions and allowed to ride on their parent atoms with d(O—H) = 0.82 Å, d(C—H) = 0.93 Å, and Uiso(H) = 1.2 Ueq(C), Uiso(H) = 1.5 Ueq(O), respectively. The hydrogen atoms at the ethanol molecule (C8, C9 and O6) were not located. The site occupancy of the ethanol molecule was determined according to its electron density. The same coordinate and anisotropic displacement parameters are used for O6 and C9 during the refinement. Discussion The symmetry independent unit of the crystal structure of the title compound consists of one Co(II) ion, one chelidamate ligand, three coordinated water molecules, one lattice water molecule, and a quater ethanol molecule. The Co(II) ion is coordinated by one N atom and two O atoms from the tridentate chelidamate ligands and three coordinated water molecules forming a distorted octahedron (figure, top). The equatorial plane consists of N and O atoms from the chelidamate ligands and one coordinated water molecule (O3W), the axial positions are occupied by two water molecules (O1W and O2W). The Co—O bond distances range from 2.025(2) to 2.209(3) Å, which fall in the normal range reported for the cobalt complexes [1-3]. The bond distance of Co—N (2.030(3) Å) is close to the values reported in the cobalt complexes [2,3]. Similar to the cobalt complex with chelidamate ligands [2], the discrete cobalt complexes in the title crystal structure are linked by the hydrogen bonds between the atoms O1 and O5, and O3W and O4 to form an infinite chain along [100]. And the neighbor chains are connected into a layer in (001) through the hydrogen bonds between O1W and O2, O2W and O2 (figure, bottom). These layers are in turn inter-linked through a very complex hydrogen bonding network involving water molecules and oxygen atoms from the chelidamate ligands to form a 3D supramolecular framework. Z. Kristallogr. NCS 225 (2010) 315-316 / DOI 10.1524/ncrs.2010.0137 315

Crystal structure of triaqua-(4-hydroxypyridine-2,6-dicarboxy- N,0,0')cobalt(II) monohydrate, Co(H2O)3(C7NO5H3) · H2O

C7H11C0NO9, monoclinic, P2\/n (no. 14), a = 11.886(2) Â, b = 8.213(1) Â,c = 12.189(2) Â,/? = 117.724(2)°, V = 1053.3 À, Ζ = 4, Rgt(F) = 0.025, w R ^ F ) = 0.081, Γ= 293 Κ. Source of material A mixture of cobalt(II) chloride dihydrate (0.25 mmol, 0.042 g), 1,10-phenanthroline (0.25 mmol, 0.045 g), chelidamic acid (0.25 mmol, 0.05 g,) and H2O (10 ml) was loaded into a 25 ml sealed Teflon-lined autoclave, and heated at 413 Κ for 4 days, then cooled to room temperature. Purplish-red prismatic crystals were obtained by filtration of the resulting solution. Experimental details Η atoms of water molecules (01W, 02W, 03 W, and 04W) were found in difference Fourier map and refined with f7iso(H) =1.5 Ueq(O). The Η atom of C4, C2, and 05 were placed in calculated positions and allowed to ride on their parent atoms with d(0—H) = 0.82 Â, d(C—H) = 0.93 Â, and í/¡so(H) = 1.2 t/«,(C), ί/ί*,(Η) = 1.5 t/eq(O), respectively. Discussion The symmetry independent part of the crystal structure of the title compound consists of one Co atom, one chelidamic acid ligands, three coordinated water molecules, and one isolated water molecules. The Co(II) atom is coordinated by one Ν atom and two O atoms from the tridentate chelating chelidamic acid ligands and three water molecules to form a distorted octahedron (figure, top). The equatorial plane consists of Ν and O atoms from the chelidamic acid ligands and one oxygen from a water molecule (01W), the axial positions are occupied by two oxygens from water molecules (02W and 03W). The bond distances of Co—O range from 2.049(2) to 2.198(1) Â, which falls in the normal range reported for the cobalt complexes in the literature [1-3]. The bond distance of Co—Ν (2.020(2) Â) is close to the normal values reported in the cobalt complexes [2,3]. The cobalt complexes are linked by the hydrogen bonds between the atoms OI W and 02 to form a infinite chain along [010]. The neighbouring chains are connected into a layer in the (100) plane through the hydrogen bonds between 02W and 03W, as well as 03 and 05 (figure, bottom). The layers are in turn interlinked through a complex hydrogen bonding network involving water molecules and oxygen atoms from the chelidamic acid ligands to form a 3D network. Table 1. Data collection and handling. Crystal: Wavelength: