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Surface complexation modeling of Eu(Ⅲ) adsorption on silica in the presence of fulvic acid

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Science China Chemistry 2014年第9期57卷 1276-1282页

作者： YE YuanLv CHEN ZongYuan MONTAVON Gilles JIN Qiang GUO ZhiJun wu wangsuo Radiochemistry Laboratory School of Nuclear Science and TechnologyLanzhou University Laboratoire SUBATECH UMR 6457 CNRS-IN2P3/Ecole des Mines de Nantes/PRES UNAM4 rue A. Kastler 44307 Nantes CedexFrance

Humic substances （HS） substantially affect heavy metal （M） adsorption on mineral surfaces. However, quantitative descriptions of ternary systems involving M, HS and mineral surfaces remain unclear. This study examines adsorption in a model ternary system including Eu（III）, fulvic acid （FA） and silica, and describes the adsorption of Eu（III） and FA by combining a double-layer model （DLM） and the Stockholm humic model （SHM）. SHM explains the binding of H＋ and Eu^3＋ to EA and the DLM for FA and Eu（Ill） adsorption on silica. Experimental results showed that the presence of FA promotes Eu（III） adsorp- tion at acidic pH values, but decreases it at basic pH values, which indicates the formation of ternary surface complexes. Modeling calculations have shown that two ternary surface complexes are required to describe the experimental results in which Eu^3＋ acts as a bridge between the surface site and FA. The present study suggests that the discrete-site approach to HS is a promising method for interpreting the adsorption data for M, HS and mineral ternary systems.

关键词： Eu(III) fuivic acid adsorption silica Stockholm humic model

Influence of FeCl_3 on radiation stability of ionic liquid BmimCl

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Chinese Science Bulletin 2013年第10期58卷 1150-1155页

作者： HUANG Lei HUANG Wei FU HaiYing wu GuoZhong GUO ZhiJun wu wangsuo CHEN ShiMou Shanghai Institute of Applied Physics Chinese Academy of Sciences Radiochemistry Labaratory School of Nuclear Science and TechnologyLanzhou University Institute of Process Engineering Chinese Academy of Sciences

This study investigates the effect FeCl3 on the radiation stability of the ionic liquid,1-butyl-3-methylimidazolium chloride(BmimCl) over a wide dose range of 0 to 1000 kGy under γ-ray *** ionic liquid species,BmimFeCl4,was formed by adding FeCl3 into *** results showed that the presence of FeCl4-significantly improved the radiation resistance of BmimCl,wherein the effect was more pronounced at higher ***,under irradiation,Fe(II) was generated from Fe(III),which was reduced by solvated *** addition,the concentration of Fe(II) increased with low level of absorbed dose,but leveled off at higher ***,the radiation yield of the solvated electrons of BmimCl was further estimated at approximately 0.358±0.01 μmol/J in BmimCl-7 mol% FeCl3 system.

关键词：辐射稳定性三氯化铁离子液体甲基咪唑射线辐射耐辐射性浓度增加溶剂化

Modeling of radionickel sorption on MX-80 bentonite as a function of pH and ionic strength

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Science China Chemistry 2009年第3期52卷 362-371页

作者： SHAO DaDong XU Di WANG SuoWei FANG QiaoHui wu wangsuo DONG YunHui WANG XiangKe Institute of Plasma Physics Chinese Academy of SciencesHefei 230031China College of Chemical Engineering Shandong University of TechnologyZibo 255049China Radiochemistry Laboratory School of Nuclear Science and TechnologyLanzhou UniversityLanzhou 730000China

MX-80 bentonite was detected using acid-based titration, XRD and FTIR in detail. The sorption behavior of 63Ni(II) from aqueous solution to MX-80 bentonite was investigated as a function of solid content, ionic strength and pH by using batch technique. The experimental data of 63Ni(II) sorption on MX-80 bentonite was obtained using the diffuse layer model (DLM) with the aid of FITEQL 3.1 program. The results indicated that the sorption of 63Ni(II) on MX-80 bentonite was mainly dominated by surface complexation, and cation exchange also contributed partly to 63Ni(II) sorption at low pH values. The sorption isotherms were simulated by Langmuir and Freundlich models, and the results indicated that Freundlich isotherm model fitted the sorption data better than the Langmuir isotherm model. The results are crucial to evaluate the sorption and migration of radionickel in MX-80 bentonite.

关键词： MX-80 bentonite radionickel acid-based titration sorption modeling

Sorption of uranyl ions on TiO_2:Effects of pH,contact time,ionic strength,temperature and HA

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Journal of Environmental Sciences 2019年第1期31卷 115-123页

作者： Jingjing Wang Bihong He Xiaoyan Wei Ping Li Jianjun Liang Shirong Qiang Qiaohui Fan wangsuo wu Radiochemistry Laboratory School of Nuclear Science and Technology Lanzhou University Key Laboratory of Petroleum Resources Gansu Province/Key Laboratory of Petroleum Resources Research Institute of Geology and GeophysicsChinese Academy of Sciences Key Laboratory of Preclinical Study for New Drugs of Gansu Province Institute of Physiology School of Basic Medical SciencesLanzhou University

Sorption of U(VI) onto TiO_2 as functions of pH, ionic strength, contact time, soil humic acid(SHA), solid-to-liquid ratio and temperature was studied under ambient conditions using batch and spectroscopic approaches. The sorption of U(VI) on TiO_2 was significantly dependent on pH and ionic strength. The presence of SHA slightly enhanced the sorption of U(VI) on TiO_2 below pH 4.0, while it inhibited U(VI) sorption in the higher pH range. U(VI)sorption on TiO_2 was favored at high temperatures, and the sorption process was estimated to be endothermic and spontaneous. Reduction of U(VI) to lower valent species was confirmed by X-ray photo-electron spectroscopy analysis. It is very interesting to find that U(VI) sorption on TiO_2 was promoted in solutions with higher back-ground electrolyte concentrations. In the presence of U(VI), higher back-ground electrolyte made more TiO_2 particles aggregate through(001) facets, leading more(101) facets to be exposed. Therefore, the reduction of U(VI) was enhanced by the exposed(101) facets and more U(VI) removal was observed.

关键词： Sorption Uranium TiO2 Ionic strength Soil humic acid

Efficient photoreduction strategy for uranium immobilization based on graphite carbon nitride/activated carbon nanocomposites

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Chinese Chemical Letters 2022年第7期33卷 3581-3584页

作者： Shuyang Li Zhiwei Niu Duoqiang Pan Zhenpeng Cui Hewen Shang Jie Lian wangsuo wu Frontiers Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China Key Laboratory of Special Function Materials and Structure Design Ministry of EducationLanzhou 730000China

Uranium removal from aqueous solutions using environmentally friendly photocatalytic technology is a novel approach for resource ***,carbon nitride/activated carbon composite materials(CN/AC)were investigated for U(Ⅵ)reduction under visible *** exceptional boost in photocatalytic activity was observed for CN/AC composites(up to 70 times over the conventional bulk g-C_(3)N_(4)).The strong interactive conjugatedπ-bond structure between g-C_(3)N_(4) and AC accelerated the migration of carriers and then prolonged the electron ***/AC composites exhibited excellent compatibility with different water substrates and were resilience to a wide range of p H changes and abundant competitive anions/*** experiments and electron microscopy characterization indicated that U(VI)was reduced by photogenerated electrons and deposited on the edge of CN/AC *** low-cost,high-performance carbon-based composite material proposed in this work is a potential candidate for the efficient treatment of radioactive wastewater.

关键词： Uranium removal Photoreduction Graphitic carbon nitride Activated carbon Composite material

Adsorption of thorium(IV) on magnetic multi-walled carbon nanotubes

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Science China Chemistry 2014年第11期57卷 1483-1490页

作者： LIU Peng QI Wei DU YaoFang LI Zhan WANG Jing BI JuanJuan wu wangsuo Radiochemistry Laboratory Lanzhou University Institute of Modern Physics Chinese Academy of Sciences State Key Laboratory of Applied Organic Chemistry Lanzhou University

The influences of pH, contact time, solid-liquid ratio, temperature and C60(C(COOH)2)n on Th(IV) adsorption onto the magnetic multi-walled carbon nanotubes(MMWCNTs) were studied by batch technique. The dynamic process showed that the adsorption of Th(IV) onto MMWCNTs could reach equilibrium in 40 h and matched the pseudo-second-order kinetics model. The adsorption of Th(IV) onto MMWCNTs was significantly dependent on pH values, the adsorption ratio increased markedly at pH 3.0–5.0, and then maintained a steady state as pH values increased. At low pH, different C60(C(COOH)2)n content could enhance the adsorption content of Th(IV) onto MMWCNTs, but restrained it at higher pH. Through simulating the adsorption isotherms by Langmuir, Freundlich and Dubini-Radushkevich models, it could be seen respectively that the adsorption pattern of Th(IV) onto MMWCNTs was mainly surface complexation, and that the adsorption process was endothermic and irreversible.

关键词： Th(IV) adsorption MMWCNTs water-soluble fullerene

The sorption mechanisms of Th(Ⅳ) on attapulgite

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Science China Chemistry 2011年第7期54卷 1138-1147页

作者： PAN DuoQiang FAN QiaoHui DING KeFei LI Ping LU Yan YU Tao XU Jiang wu wangsuo Radiochemistry Laboratory School of Nuclear Science and Technology Lanzhou University Lanzhou 730000 China

The surface properties of intrinsic and activated attapulgite were studied using potentiometric titration. The sorption mechanisms of Th（IV） on intrinsic and activated attapulgite were investigated by employing surface complexation model and FITEQL 3.2 code. The results indicated that the sorption sites of intrinsic attapulgite involved in the sorption process were main ion exchange site （ ≡ XNa/K）, strong site （≡ SsOH） and weak site （ ≡ SwOH）, while only strong site （ ≡SSOH） and weak site （≡SwOH） were predominant for activated attapulgite. At pH 〈 2.5, the species of Th（IV） was main Th4＋ in aqueous solution; then the hydrolysis species of Th（IV）（i.e., Th（OH）22＋, Th（OH）3＋ and Yh（OH）40） gradually formed as pH increasing. For the sorption of Th（IV） on intrinsic attapulgite, both ion exchange species （ ≡ X2Th） and inner-sphere surface complexes （ ≡ SsOTh） were dominant, while only inner-sphere surface complexes （i.e., ≡SSOThOH and ≡ SWOTh） were observed for Th（IV） sorption to activated attapulgite. In the presence of humic acid （HA）, the sorption of Th（IV） on activated attapulgite was obviously enhanced; and both ≡ SsOH-HA-Th and≡ SSOTh were the predominant speciation. It was also interesting to find that the addition of HA obviously provoked the desorption behavior of Th（IV）.

关键词： attapuigite Th(IV) HA sorption desorption surface complexation model

Effects of oxygen vacancy on bond ionicity,lattice energy,and microwave dielectric properties of CeO_(2) ceramics with Yb^(3+) substitution

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Journal of Advanced Ceramics 2024年第2期13卷 247-254页

作者： Mingan Shi Shuyang Ma wangsuo Xia Ying Wang Jinzi Yu Haitao wu School of Materials Science and Physics China University of Mining and TechnologyXuzhou 221008China School of Environment and Material Engineering Yantai UniversityYantai 264005China

Novel Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0-0.8)ceramics,designed by replacing Ce^(4+)with Yb^(3+)ions were prepared by conventional oxide reaction,and the structural stability of the cubic fluorite structure was assessed using lattice energy and ionic properties of Ce/Yb-O *** oxygen vacancy caused by unequal substitution,which played a decisive role in bond ionicity and lattice energy,was analyzed experimentally by XPS and also theoretically by first *** Yb_(x)Ce_(1-x)O_(2-0.5x) ceramics maintain a stable cubic fluorite structure when x≤0.47,corresponding to the minimum lattice energy of 4142 kJ/mol with the lowest ionicity as ƒ_(i)=87.57%.For microwave dielectric properties,when the Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0-0.4)ceramics are pure phase,the porosity-corrected permittivity is dependent on the bond *** Q×ƒ values are related to the lattice energy and grain *** temperature coefficient of resonance frequency has been analyzed using bond *** the Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0.5-0.8)ceramics are multiple phases,the microwave dielectric properties are associated with the phase composition and grain growth.

关键词： structure stability bond ionicity oxygen vacancy electronic localization function(ELF)

Eu(III) adsorption on rutile:Batch experiments and modeling

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Science China Chemistry 2010年第12期53卷 2628-2636页

作者： WANG XueFeng,SHI KeLiang,GUO ZhiJun & wu wangsuo Radiochemistry Lab,School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China 1. Radiochemistry Lab School of Nuclear Science and Technology Lanzhou University Lanzhou 730000 China

Eu(III) adsorption on rutile was investigated as a function of contact time,pH,ionic strength and Eu(III) concentration by using a batch experimental *** effects of carbonate,sulfate,and phosphate were also *** was found that the kinetics of Eu(III) adsorption on rutile could be described by a pseudo-second-order *** adsorption of Eu(III) on rutile is strongly pH-dependent,but relatively insensitive to ionic strength.A double layer model (DLM) with two inner-sphere Eu(III) surface complexes was applied to quantitatively interpret the adsorption of Eu(III) on *** were no apparent effects of carbonate and sulfate on Eu(III) adsorption,whereas the presence of phosphate promoted Eu(III) adsorption on *** surface complexes of Eu(III) on rutile were evidenced by X-ray photoelectron spectroscopy (XPS).

关键词： Eu(III) adsorption rutile kinetics surface complexation modeling XPS