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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

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

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

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

Surface charge property governing co-transport of illite colloids and Eu(Ⅲ) in saturated porous media

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Chinese Chemical Letters 2023年第11期34卷 248-254页

作者： Xiaoyan Wei Duoqiang Pan Qi Tan Xinyi Shi Junjun Hou Qingfeng Tang Zhen Xu wangsuo wu Bin Ma Frontiers Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China Laboratory for Waste Management Paul Scherrer Institut(PSI)CH-5232 Villigen PSISwitzerland School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China

The transport of colloids and radionuclides is sophisticated because of the variety of charge properties between colloidal particles and host subsurface media, which causes great difficulty in establishing a reliable model of radionuclides migration by taking the colloid phase into consideration. In this work,the co-transport of illite colloids(IC) and Eu(Ⅲ) in the quartz sand and iron-coated sand porous media was investigated by column experiments to address the predominant mechanism of charge properties on co-transport. Results showed that Eu(Ⅲ) transport was driven by the illite colloids and electrostatic interaction was critical in governing the co-transport patterns. The promotion of Eu(Ⅲ) transport by IC was attenuated in the iron-coated sand systems;more IC-Eu(Ⅲ) complexes were retained uniformly in the column. The pore throat shrinkage caused by electrostatic attachment between aggregated IC and iron oxides exacerbated the physical straining and size exclusion effect of IC-Eu(Ⅲ) complexes. An aggravated irreversible retention of IC-Eu(Ⅲ) was detected in iron-coated sand column due to the electrostatic attraction of IC-Eu(Ⅲ) to host media. The findings are essential for improving the understanding on the potential transport, retention and release risk of colloids associated radionuclides, and imply that the positively charged permeable reactive barrier is an effective strategy to reduce the transport risk of colloid associated radionuclides.

关键词： Illite colloids Eu(Ⅲ) Co-transport Release Charge property

China's progress in radionuclide migration study over the past decade(2010–2021):Sorption,transport and radioactive colloid

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Chinese Chemical Letters 2022年第7期33卷 3405-3412页

作者： Zongyuan Chen Siyuan Wang Huijuan Hou Kang Chen Pengyuan Gao Zhen Zhang Qiang Jin Duoqiang Pan Zhijun Guo wangsuo wu Frontiers Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China The Key Laboratory of Special Function Materials and Structure Design Ministry of EducationLanzhou UniversityLanzhou 730000China Radiochemistry Laboratory School of Nuclear Science and TechnologyLanzhou UniversityLanzhou 730000China

The radionuclide(RN)migration study is not only helpful to understand environmental behavior of RNs,but also can establish the basis for the safety assessment of geological disposal of high-level radioactive waste(HLW).In the context of China’s HLW disposal,this review briefly summaries the progress of China’s RN migration studies over the past decade regarding three aspects,RN sorption,RN transport and radioactive *** studies from other disciplines(such as geology and environmental science)are also included in this review because they can provide references for the RN migration ***,China has achieved clear progress in RN migration study over the past decade,although large-scaled field experiments are lacked and a gap still exists comparing with the international advanced ***,several suggestions are proposed for future RN migration research in China.

关键词： High-level radioactive waste Sorption Transport Colloid Spectroscopic analysis Theoretical calculation

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 Radiochemistry Lab School of Nuclear Science and Technology Lanzhou University Lanzhou 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