Zhejiang California International Nano Systems Institute

Hangzhou, China

Zhejiang California International Nano Systems Institute

Hangzhou, China
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Ren C.,Zhejiang University | Ding X.,Zhejiang University | Ding X.,Zhejiang California International Nano Systems Institute | Fu H.,Zhejiang University | And 4 more authors.
RSC Advances | Year: 2017

To remove heavy metals from aqueous solutions, amino-functionalized superparamagnetic CoFe2O4@SiO2 (CoFe2O4@SiO2-NH2) core-shell nanospheres were designed and constructed. In particular, well-defined CoFe2O4 nanoparticles (NPs) were synthesized by reverse co-precipitation. The shell of the CoFe2O4 NPs was composed of amorphous silica (SiO2), which had a thickness of ∼35 nm. Monodisperse CoFe2O4@SiO2 nanospheres grafted with more amino groups had a greater adsorption capacity and higher removal efficiency for heavy metal ions (Cd(ii): 199.9 mg g-1, 99.96%; Cu(ii): 177.8 mg g-1, 88.05%; Pb(ii): 181.6 mg g-1, 90.79%). The effects of the pH, initial concentrations, reaction temperature and time on the adsorption of heavy metal ions by CoFe2O4@SiO2-NH2 were analyzed systematically. The adsorption process on the nanospheres was well described by the Langmuir model. The adsorption kinetics can be best fitted by the pseudo-second-order kinetics model. Analysis of a thermodynamic study of Cu(ii) showed that the process of adsorption is spontaneous and endothermic in nature. Owing to the superparamagnetic properties with a high saturation magnetization value (32.92 emu g-1) of CoFe2O4@SiO2-NH2, the metal-loaded nanospheres can be quickly removed from an aqueous solution (30 s) by magnetic separation. Moreover, the nanospheres exhibited good reusability for up to five cycles. The results confirm that the monodisperse amino-functionalized CoFe2O4@SiO2 magnetic nanospheres could be a potential adsorbent for the effective and regenerable removal of heavy metals from aqueous solutions. © 2017 The Royal Society of Chemistry.


Fu H.,Zhejiang University | Ding X.,Zhejiang University | Ding X.,Zhejiang California International Nano Systems Institute | Ren C.,Zhejiang University | And 4 more authors.
RSC Advances | Year: 2017

In this work, a novel magnetic porous adsorbent was prepared via a sol-gel method for the removal of Ce(iv) from aqueous solution. The NiFe2O4/SiO2 composite xerogels were characterized using SEM, BET, FT-IR, XPS, TEM, VSM and XRD. In addition, the effects of initial concentration, amounts of adsorbents, contact time, solution pH and temperature on the adsorption of Ce(iv) were investigated via batch adsorption studies. The results verify the formation of hierarchically porous structures with a specific surface area of 1085.3 m2 g−1. The adsorption capacity for Ce(iv) at 25 °C is 114.56 mg g−1 (91.65%), the adsorption of Ce(iv) onto the composite xerogels was better described by the pseudo-second-order kinetic model, and the data fit well with the Langmuir isotherm model. Thermodynamic parameters such as standard enthalpy (ΔH0), standard entropy (ΔS0) and standard free energy (ΔG0) indicated that the adsorption of Ce(iv) onto composite xerogels was spontaneous and endothermic within the temperature range of 278-338 K. Moreover, the adsorbents showed good performance and recycling ability and could be separated by applying a magnetic field. © The Royal Society of Chemistry.


Li P.,Zhejiang University | Ding X.,Zhejiang University | Ding X.,Zhejiang California International Nano Systems Institute | Yang H.,Zhejiang University | And 3 more authors.
Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society | Year: 2012

The zirconolite-based glass-ceramics were prepared with SiO 2, Al 2O 3, B 2O 3, CaO, TiO 2 and ZrO 2 as raw materials and CeO 2 of 3% (in mass fraction, the same below) as simulated nuclide by a melting method for the disposal of actinides-containing radioactive waste solidification. The glass-ceramics obtained after heat treatments were characterized by X-ray diffraction and field emission scanning electron microscopy, respectively. The leaching resistance performance of glass-ceramics was analyzed via inductively coupled plasma mass spectra. The results show that the zirconolite crystals in the glass-ceramics could be more readily formed by lower mass fraction of TiO 2 and ZrO 2 at B 2O 3 of 12.5%. Single crystalline phase of zirconolite could be easily formed at the same crystallization temperature and with 8.33% B 2O 3, and the glass-ceramics had better leaching resistance performances, its normalized leaching rate of Ce remained at 10 -6 of magnitude after 7 d with the product consistency test method, and the curing effect was obvious.


Meng C.,Zhejiang University | Ding X.,Zhejiang University | Ding X.,Zhejiang California International Nano Systems Institute | Zhao J.,Zhejiang University | And 4 more authors.
Journal of the European Ceramic Society | Year: 2016

Rare-earth phosphates (REPO4) represent one candidate to contain minor actinides separated from used nuclear fuel. In this work, the Gd1-xYbxPO4 (0≤x≤ 1) series is synthesized via conventional solid-state reaction using Gd as the surrogate for trivalent actinides (Am, Cm), with microstructure/phase structure characterized by XRD, XPS, HRTEM and SEM as well. Solid solutions of monazite- and xenotime-type compounds are observed in the system. The structural boundary between two phases is based on the experimental temperature. The monazite→xenotime transformation is most likely to occur on a (200) monazite plane along the [020] zone. The pure xenotime-type crystalline phase with Gd0.9Yb0.1PO4 composition is obtained at 1600°C. © 2015 Elsevier Ltd.


Meng C.,Zhejiang University | Ding X.,Zhejiang University | Ding X.,Zhejiang California International Nano Systems Institute | Zhao J.,Zhejiang University | And 4 more authors.
Progress in Nuclear Energy | Year: 2016

Monazites are of considerable interest for immobilization of minor actinides. In this work, the Gd1-xCexPO4 (0 ≤ x ≤ 1) series is synthesized via conventional solid-state reaction using Ce as the surrogate for minor actinide americium (Am), with microstructure/phase structure characterized by XRD, HRTEM, μ-Raman, and SEM as well. The optimized temperature for preparation of monazite-type Gd0.4Ce0.6PO4 solid solution is more than 1300 °C. At 1400 °C, the GdPO4 ceramic is essentially monazite with little metastable xenotime phase. The metastable xenotime (GdPO4) to monazite transformation occurs during the immobilizing phase of Ce element. The formation of monazite-type Gd1-xCexPO4 solid solutions in the range 0.1 ≤ x ≤ 1 is confirmed by the Rietveld refinement and Raman spectra. The change of Ce content has no significant influence on the morphology of the monazite-type Gd1-xCexPO4 compounds. © 2016 Elsevier Ltd. All rights reserved.


Dong Z.,Zhejiang University | Ren Z.,Zhejiang University | Wu C.,Zhejiang California International Nano Systems Institute | Pan C.,Zhejiang California International Nano Systems Institute | And 2 more authors.
Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society | Year: 2013

Nano-composite sols were prepared using methyltrimethoxysilane as a precursor and commercial silica sols and boehmite sols as nano-phase materials, and the anti-corrosion coatings were deposited on the surface of aluminium plates via a spin method. The effect of curing temperature on the structure and performance of the composite coatings was investigated by thermogravimetry-differential thermal analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, electrochemical impedance spectroscopy and contact angle measurement, respectively. The results show that the composite coatings are stable at <400 °C, and the methyl group (-CH3) in the coatings decomposes gradually at > 400 °C. The coating thickness is 10 (m. The coating prepared in the curing temperature range of 120-240 °C is dense. The coating can crack at 640 °C. The contact angle of the coating decreases from 106°to 20°, the pencil hardness of the coating increases from 3H to 6H, and the adhesion, impact strength and impedance of coatings firstly increases and then decreases with increasing the curing temperature. The optimum impact strength and impedance of the coating obtained at 180 °C are 45 cm/kg and 2.95 × 103(·cm2, respectively.


Ren C.,Zhejiang University | Ding X.,Zhejiang University | Ding X.,Zhejiang California International Nano Systems Institute | Fu H.,Zhejiang University | And 4 more authors.
RSC Advances | Year: 2016

Amino-functionalized nanocomposites with a magnetic CoFe2O4 core and an amorphous SiO2 shell have been designed and synthesized. The core-shell structure was characterized by SEM, EDS, TEM, FTIR and XPS. CoFe2O4@SiO2-NH2 with a high saturated magnetization (28.09 emu g-1) can be easily separated under a moderate external magnetic field within one minute. In addition, the adsorption capacity of the CoFe2O4@SiO2-NH2 for Cu(ii), Cd(ii) and Mn(ii) was 170.829, 144.948 and 110.803 mg g-1, respectively. The removal efficiency was increased from 12 to 85% with an increase in the pH from 4 to 6.5. The adsorbent can be recycled for at least four cycles with a feasible removal efficiency (85.41%). The adsorption process was fitted by pseudo-second-order kinetics and a Langmuir isotherm model. Based on the data of the present investigation, CoFe2O4@SiO2-NH2 could find potential applications in heavy metal ion wastewater treatment. © The Royal Society of Chemistry 2016.


Fu H.,Zhejiang University | Ding X.,Zhejiang University | Ding X.,Zhejiang California International Nano Systems Institute | Ren C.,Zhejiang University | And 4 more authors.
Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society | Year: 2016

A magnetic porous aerogel composite was prepared via a sol-gel method and in-situ synthesis of Ni/Cu ferrite spinel. The microstructure, magnetism and adsorption ability were characterized. The results show that the organic molecular chain of glycollic acid in precursor is combined with inorganic phase to form the skeleton and the doublely-connected pore structure, the porosity of as-synthesized composite aerogels is 73.22%, and the bulk density is 0.36 g/cm3, with an average grading of 16 µm; the magnetic nanoparticles distribute uniformly in the SiO2 matrix. The specific surface area of samples decreases and the saturation magnetization increases with the increase of the calcination temperature. The composite as-prepared presents a maximum capacity of 100.67 mg/g, can adsorb Ce(IV) from aqueous solution at a a superior performance of recycle ability, and can be separated by a magnetic field. © 2016, Editorial Department of Journal of the Chinese Ceramic Society. All right reserved.


Zhao J.,Zhejiang University | Ding X.,Zhejiang University | Ding X.,Zhejiang California International Nano Systems Institute | Meng C.,Zhejiang University | And 4 more authors.
Progress in Nuclear Energy | Year: 2015

The novel SiO2-ZrO2-calcium alginate aerogels were prepared by Sol-Gel process with phase separation method for investigating the adsorption and immobilization performance of the plutonium and minor actinides from high-level liquid waste (HLLW). The materials contained porous network structure with high surface area (233.44-481.08 m2/g) and pore volume (0.50-1.26 m3/g). The aerogels were superior adsorbents for the removal of plutonium and minor actinides, the maximum adsorption capacity and adsorption rate (35 °C, 75 rpm) reached 231.5 mg/g and 99.2%. For all the waste forms, SiO2, ZrO2 and Ca2SiO4 phases were simultaneously observed in the matrix. Moreover, Ce entered into Ca sites of Ca2SiO4 and Zr sites of ZrO2. The substitution of Ca and Zr by Ce in the Ca2SiO4 and ZrO2 implies a promising disposal measure of actinides. © 2015 Published by Elsevier Ltd.


Meng C.,Zhejiang University | Ding X.,Zhejiang University | Ding X.,Zhejiang California International Nano Systems Institute | Li W.,Zhejiang University | And 3 more authors.
Journal of Materials Science | Year: 2016

The Ca1−xZr1−xCe2xTi2O7+δ (0 ≤ x ≤ 0.4) series is synthesized via chemical routes, with microstructure/phase structure characterized by XPS, XRD, HRTEM, and SEM as well. The partial reduction of Ce4+ in Ce3+ in Ca1−xZr1−xCe2xTi2O7+δ ceramics is observed from the Ce 3d XPS spectra. The XRD investigations and Rietveld refinements show that there are three crystal structures, namely monoclinic zirconolite-2M or zirconolite-4M, tetragonal perovskite, and cubic pyrochlore. The Ca and Zr sites of zirconolite structure are occupied by Ce3+ and Ce4+ ions, respectively. The zirconolite-2M → zirconolite-4M → pyrochlore transformation is based on the extent of Ce3+ and Ce4+ substitution. The zirconolite-4M phase tends to form at slightly higher substitution levels of Ce3+ and Ce4+ ions. At high substitution levels of Ce3+ and Ce4+ ions, cation rearrangement occurs resulting in the formation of pyrochlore structure. The chemical durability test is measured by the ASTM Product Consistency Test leaching method, and the normalized mass loss (NLCe) of Ce in the Ca1−xZr1−xCe2xTi2O7+δ ceramics is shown in the order of 10−6–10−7 g/m2. © 2016, Springer Science+Business Media New York.

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