Co-reporter:Fuyin Ma, Zheng Li, Haogui Zhao, Yiyun Geng, Wei Zhou, Qingnuan Li, Lan Zhang
Separation and Purification Technology 2017 Volume 188(Volume 188) pp:
Publication Date(Web):29 November 2017
DOI:10.1016/j.seppur.2017.07.062
•The permeation rates of Cs(I) and Sr(II) through GO membranes were much higher than that of lanthanide and actinide ions.•The permeation rates of ions through GO membranes markedly decreased with the increase of hydrated ionic radii.•The GO membrane is a promising candidate for the removal of Cs(I) and Sr(II) from HLLW.As a new carbon-based membrane material used for ionic and molecular sieving, the graphene oxide (GO) membrane also has potential application in radiochemical separation. In this work, the permeation performances of some typical metallic elements in high level-liquid waste (HLLW) through the ionic sieving 5-μm-thick GO membranes were investigated. It was found that the permeation rates of ions through GO membranes markedly decreased with the increase of hydrated ionic radii. Cs(I) and Sr(II) permeated through GO membranes quickly, whereas lanthanide ions and actinide ions infiltrated much more slowly, thus providing the feasibility of separation according to the difference of hydrated ionic radii. Moreover, the concentrations of initial metal ions and acidity in feed solutions also had influences on the permeation of ions through GO membranes, and higher initial metal ions and feed solution acidity were favorable to the removal of Cs(I) and Sr(II). The barrier separation test indicated that GO membranes had promising ability for the separation of Cs(I) and Sr(II) from lanthanide and actinide ions due to the difference of hydrated ion radius, and the separation factor of Cs(I)/U(VI) and Sr(II)/U(VI) would reach about 10 and 3 in single penetration. The presented results demonstrated that the membrane separation based on GO membrane would be a promising candidate for the removal of Cs(I) and Sr(II) from HLLW.Download high-res image (76KB)Download full-size image
Co-reporter:Xianbin Wang, Wei Huang, Yu Gong, Feng Jiang, Haiyang Zheng, Tiejian Zhu, Dewu Long, Qingnuan Li
Electrochimica Acta 2016 Volume 196() pp:286-293
Publication Date(Web):1 April 2016
DOI:10.1016/j.electacta.2016.02.184
The electrochemical behavior of Th(IV) ion on molybdenum (Mo) electrode was studied by cyclic voltammetry (CV) and square wave voltammetry (SWV) technologies at 773 K in ThF4-LiCl-KCl melt. The reduction of Th(IV) to metal Th at −1.67 V (vs. Ag/AgCl) is a four-electron exchange process, which is quasi-reversible and diffusion-controlled. The diffusion coefficient (D) and activation energy of diffusion process for Th(IV) were determined to be 3.77 × 10−5 cm2 s−1 and 59.2 kJ mol−1. The pulse potential electrolysis of ThF4-LiCl-KCl melt revealed that 86.8% of Th(IV) can be separated from the melt based on the inductively coupled plasma atomic emission spectrometer (ICP-AES) results.
Co-reporter:Mengling Tan, Chao Huang, Songdong Ding, Fang Li, Qingnuan Li, Lan Zhang, Chunxia Liu, Shimeng Li
Separation and Purification Technology 2015 Volume 146() pp:192-198
Publication Date(Web):26 May 2015
DOI:10.1016/j.seppur.2015.03.027
•Extraction power and selectivity of DMHMP are much higher than those of TBP.•There is no third phase in the extraction of sat. Th(NO3)4 with 30 vol.% DMHMP/kerosene.•For the first time, the solubility of DMHMP in various nitric acid was determined.•The extraction mechanism and the thermodynamic parameters were presented.The extraction behaviors of U(VI) and Th(IV), as well as the extraction of HNO3 were investigated by using di(1-methyl-heptyl) methyl phosphonate (DMHMP) as an extractant and kerosene as a diluent. Effects of contact time, acidity, concentration of extractant and temperature on the distribution ratios of U(VI) and Th(IV) were evaluated. HNO3 was extracted as mono-solvated species. In the investigation of acidity range from 0.01 to 6.0 mol/L, the distribution ratios of U(VI) and Th(IV) increased at first with the rise of HNO3 concentration up to 3.0 mol/L and then decreased. DMHMP exhibited higher selectivity for U(VI) than for Th(IV) with the separation factor SFU/Th values of 25–120, whereas under the same conditions, tri-n-butyl-phosphate (TBP) only had SFU/Th values of 1.4–26. Slope analyses showed that U(VI) and Th(IV) were extracted as di-solvated and tri-solvated species respectively. The thermodynamic parameters (ΔH, ΔS and ΔG) were presented and revealed that the extraction was exothermic. For the extraction of Th(VI) from various HNO3 by 30 vol.% DMHMP or TBP, the limiting organic concentration (LOC) was also given. FT-IR spectra indicated that it was PO bond, not PO bond that took part in the coordination with U(VI) and Th(IV). In addition, the solubility of DMHMP and TBP in various concentration HNO3 was determined using ICP-AES, and their thermal stability in air was also examined through TGA. DMHMP has much lower water solubility and higher thermal stability than TBP.
Co-reporter:Wei Huang, Lifang Tian, Changfeng She, Feng Jiang, Haiyang Zheng, Wenxin Li, Guozhong Wu, Dewu Long, Qingnuan Li
Electrochimica Acta 2014 Volume 147() pp:114-120
Publication Date(Web):20 November 2014
DOI:10.1016/j.electacta.2014.08.119
The transformation of Eu(III) to Eu(II) was confirmed in a fluoride eutectic, LiF-NaF-KF (46.5-11.5-42.0 mol%, FLiNaK) molten salt during a treatment of high temperature as high as 1023 K. The coexistence of Eu(III)-Eu(II) was characterized by X-ray photoelectron spectroscopy (XPS) and voltammetry method, and their concentrations were measured. The electrochemical behavior of Eu(III) and Eu(II) in the fluoride salt was investigated. The mechanism of the electrode reaction was determined using cyclic voltammetry (CV) and square wave voltammetry (SWV). The results indicated a one-electron exchange process, corresponding to the reduction of Eu(III) to Eu(II) and the oxidation of Eu(II) to Eu(III). This process is reversible and diffusion-controlled. The diffusion coefficients (D) of Eu(III) and Eu(II) were determined using the conventional CV by changing the scanning rate and a modified method by changing the area of the working electrode successively. The values obtained by these two different methods were consistent. The temperature dependence of diffusion coefficient was investigated, and the activation energies of diffusion process were calculated to be 38.9 ± 4.6 kJ mol-1 for Eu(III) and 34.7 ± 1.6 kJ mol-1 for Eu(II), respectively.
Co-reporter:Jilei Yin, Cheng Kang, Yufeng Li, Qinnuan Li, Xiaoyong Zhang and Wenxin Li
Toxicology Research 2014 vol. 3(Issue 5) pp:367-374
Publication Date(Web):19 Jun 2014
DOI:10.1039/C4TX00040D
With the rapid development of nanoscience and nanotechnology, comprehensive evaluation of the potential toxicity especially the respiratory toxicity of nanomaterials, has attracted great research interest over the past few decades. A numerous previous reports have utilized intratracheal instillation to imitate the physiological inhalation exposure route of nanomaterials. However, because it is a non-physiological breathing process, intratracheal instillation has many problems when it is utilized to evaluate respiratory toxicity of nanomaterials. In this study, anatase titanium dioxide (TiO2) nanoparticles with a primary particle size of 20 nm was selected as a model nanomaterial. Its respiratory toxicity has been estimated by a whole-body exposure chamber. Mice were put in the whole-body exposure chambers with a relatively steady concentration (6.34 ± 0.22 mg m−3) of inhaled TiO2 nanoparticles. In the whole study these mice were exposed 8 h per day, for 3 weeks. Results showed that these TiO2 nanoparticles inhaled might drill through air–blood barriers, be metabolized by the liver and excreted by the urinary system. After mice had been exposed to TiO2 nanoparticles, H2O2 and maleic dialdehyde (MDA) in brain homogenate extracts had clearly increased. The white blood cell (WBC) count was decreased while platelet (PLT) and reticulocyte (Retic) counts increased significantly. At the same time, the prothrombin time (PT) of mice in the inhalation exposure group was shorter than the control group's. Furthermore, compared with the control group's, the levels of ALT, AST, BUN and CREA in the inhalation exposure group were elevated. Given the whole body exposure method is a physiological exposure route, the results reported in this work should be more suitable for evaluation of the respiratory toxicity of nanomaterials.
Co-reporter:Yongjun Li;Sen Zhang;Hao Liu;Wenxin Li;Xiaoyu Huang
Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 23) pp:5419-5429
Publication Date(Web):
DOI:10.1002/pola.24347
Abstract
A series of perfluorocyclobutyl (PFCB) aryl ether-based amphiphilic diblock copolymers containing hydrophilic poly(acrylic acid) (PAA) and fluorophilic poly(p-(2-(p-tolyloxy)perfluorocyclobutoxy)phenyl methacrylate) segments were synthesized via successive atom transfer radical polymerization (ATRP). 2-MBP-initiated and CuBr/N,N,N′,N′,N″-pentamethyldiethylenetriamine-catalyzed ATRP homopolymerization of the PFCB-containing methacrylate monomer, p-(2-(p-tolyloxy)perfluorocyclobutoxy)phenyl methacrylate, can be performed in a controlled mode as confirmed by the fact that the number-average molecular weights (Mn) increased linearly with the conversions of the monomer while the polydispersity indices kept below 1.38. The block copolymers with narrow molecular weight distributions (Mw/Mn ≤ 1.36) were synthesized by ATRP using Br-end-functionalized poly(tert-butyl acrylate) (PtBA) as macroinitiator followed by the acidolysis of hydrophobic PtBA block into hydrophilic PAA segment. The critical micelle concentrations of the amphiphilic diblock copolymers in different surroundings were determined by fluorescence spectroscopy using N-phenyl-1-naphthylamine as probe. The morphology and size of the micelles were investigated by transmission electron microscopy and dynamic laser light scattering, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Co-reporter:Yongjun Chen;Sen Zhang;Chun Feng;Yaqin Zhang;Wenxin Li;Xiaoyu Huang
Chinese Journal of Chemistry 2009 Volume 27( Issue 11) pp:2261-2266
Publication Date(Web):
DOI:10.1002/cjoc.200990379
Abstract
Amphiphilic block copolymers containing hydrophobic perfluorocyclobutyl-based (PFCB) polyacrylate and hydrophilic poly(ethylene glycol) (PEG) segments were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization. The PFCB-containing acrylate monomer, p-(2-(p-tolyloxy)perfluorocyclobutoxy)-phenyl acrylate, was first synthesized from commercially available compounds in good yields, and this kind of acrylate monomer can be homopolymerized by free radical polymerization or RAFT polymerization. Kinetic study showed the 2,2′-azobis(isobutyronitrile) (AIBN) initiated and cumyl dithiobenzoate (CDB) mediated RAFT polymerization was in a living fashion, as suggested by the fact that the number-average molecular weights (Mn) increased linearly with the conversions of the monomer, while the polydispersity indices kept less than 1.10. The block polymers with narrow molecular weight distributions (Mw/Mn≦1.21) were prepared through RAFT polymerization using PEG monomethyl ether capped with 4-cyanopentanoic acid dithiobenzoate end group as the macro chain transfer agent (mPEG-CTA). The length of the hydrophobic segment can be tuned by the feed ratio of the PFCB-based acrylate monomer and the extending of the polymerization time. The micellization behavior of the block copolymers in aqueous media was investigated by the fluorescence probe technique.
Co-reporter:Jing-Ying Xu, Qing-Nuan Li, Jun-Gang Li, Tie-Cheng Ran, Sheng-Wei Wu, Wei-Min Song, Shao-Liang Chen, Wen-Xin Li
Carbon 2007 Volume 45(Issue 9) pp:1865-1870
Publication Date(Web):August 2007
DOI:10.1016/j.carbon.2007.04.030
An increasing number of studies have been devoted to studying the respiratory toxicity of carbon nanomaterials, but little information is known, thus far, on the biodistribution of these nanomaterials after inhalation or intratracheal instillation. We synthesized and labeled a polyhydroxylated derivative of fullerene C60(OH)x (x = 22, 24) with 99mTc. With single photon emission computed tomography imaging and 〈gamma〉-ray counting techniques, the biodistribution of 99mTc-C60(OH)x in Sprague–Dawley rats after intratracheal instillation was studied. It was found that, besides the highest retention in the lung, 99mTc-C60(OH)x is distributed mainly in the liver, bone, and spleen, with no uptake found in brain. The long-term retention in the lung and the very fast clearance from the blood revealed a transient characteristic of penetrating the alveolar-capillary barrier. The dimensions and size distribution, as well as in vivo aggregation of 99mTc-C60(OH)x, may affect the capability and kinetic process of penetrating the alveolar-capillary barrier. The results provide guidance for further study of the respiratory toxicity of carbon nanomaterials.
