四氧化三铁/氧化石墨烯纳米带复合材料对铀的吸附性能

以高锰酸钾/浓硫酸氧化法轴向切割多壁碳纳米管（MWCNTs）所制备的氧化石墨烯纳米带（GONRs）为原料,采用水热法制备了一种便于固液分离的功能性四氧化三铁/GONRs复合材料（MGONRs）,对其进行了SEM、FT-IR、XRD等表征,并考察了其对U(Ⅵ)的吸附性能。探讨了溶液pH值、MGONRs用量、铀初始浓度、吸附时间和温度对MGONRs吸附U(Ⅵ)的影响。结果表明：MGONRs对U(Ⅵ)的吸附过程是与pH值和时间相关的自发的吸热过程;吸附符合准二级动力学模型和Langmuir模型,MGONRs对U(Ⅵ)的吸附量可达123.2 mg/g,且具有良好的再生性能,有望用于从放射性废水中分离和回收铀。     

Study of radiation-induced grafting of acrylic acid-sodium styrene sulfonate onto poly （tetrafluoroethylene-cohexafluoropropylene） film

Poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) films were immersed in aqueous solution of acrylic acid (AA) and sodium styrene sulfonate (SSS), then irradiated by ^60Co γ-rays at 25℃. The effects o| reaction time, absorbed dose, dose-rate, inhibitor and monomer concentration on the grafting yield were studied. Grafting yields of both AA and SSS onto FEP, respectively, increase with irradiation dose, but some saturation will appear at high dose and monomer concentration. The grafting yield increases with reaction time and then levels off. The grafting of SSS onto FEP is more difficult than the grafting of AA. The analysis of grafted membranes using DSC and FT-IR have been done.     

辐照接枝改性涤纶织物的亲水性能

利用电子束辐照接枝的方法将丙烯酸(Acrylic acid,AA)单体接枝到涤纶织物上来改善其亲水性。通过改变吸收剂量、接枝单体浓度、阻聚剂浓度、预辐照的吸收剂量以及前处理氢氧化钠浓度等影响因素来获得具有不同接枝率的改性涤纶织物。优化的反应条件:吸收剂量为195 k Gy、AA浓度为50%、阻聚剂(Fe SO4?7H2O)浓度为0.8%、预辐照的吸收剂量为43 k Gy、前处理Na OH浓度为15 g/L。傅里叶红外光谱证明AA已接枝成功;扫描电子显微镜分析表明改性涤纶织物的表面具有覆盖物,且随着接枝率的增大,其覆盖物明显增多;回潮率测试结果表明,改性涤纶的回潮率随接枝率的增加而逐渐增大,当接枝率达到最大值27.84%时,改性涤纶的回潮率可达3.51%。涤纶织物经30次洗涤后减重率仅1%左右,说明接枝牢度优异。     

辐射接枝制备聚丙烯纤维基海水提铀吸附剂

采用电子束预辐射接枝法将丙烯腈和丙烯酸接枝于聚丙烯(Polypropylene,PP)纤维上,并探讨了吸收剂量和反应温度对接枝率的影响。随后通过偕胺肟化反应制备出含偕胺肟基和羧基的PP纤维吸附剂。红外光谱数据表明,丙烯腈和丙烯酸成功接枝到PP纤维上,偕胺肟化反应将腈基转化为偕胺肟基,同时对改性前后PP纤维的表面形貌和热性能进行了表征。厦门海域真实海水吸附性能测试结果表明,所制备的PP纤维吸附剂铀吸附容量最高可达到0.81 mg·g~(-1)(吸附时间为68 d),PP纤维吸附剂的铀吸附容量与其接枝率和偕胺肟基密度不呈正相关。     

Mutual separation of strontium, cerium, and uranium using pressure-driven flow in 100 nm-sized nanofluidic channels

We developed a novel nanofluidic control device, and demonstrated mutual separation of various metal ions in 300-3000 nm-sized nanofluidic channels. The ion concentration ratios of Sr(II), Ce(III), and U(VI) in solutions before and after nanofluidic separation treatments were measured using ICP analysis. The results showed that the mass flow rates of Sr(II), Ce(III), and U(VI) ions in nanofluidic channels were quite different. The flow rates of Ce(III) and U(VI) ions in solutions through 3000 nm-sized nanochannnels were much smaller than those of Sr(II), and increased gradually with decreasing space sizes until 300 nm. The decontamination factors of Sr(II) and Ce(III) against U(VI) were determined as 10.6 and 12.5 in 3000 nm-sized channels and 1.3 and 1.7 in 300 nm-sized channels, respectively. The ion concentration ratios of Ce(III) and U(VI) in acid solutions were also examined in 300 nm-sized channels, and the mass flow rates of Ce(III) and U(VI) were found to decrease and increase with increasing acid concentrations, respectively. Furthermore, the nanofluidic device made it possible to mutually separate U(IV) and U(VI) ions in acid solutions by flowing into nanofluidic channels.     

聚醚砜微孔膜电子辐照接枝改性及过滤性能研究

利用电子束辐照技术对聚醚砜（PES）微孔膜进行接枝丙烯酸（AA）改性。用称重法测量接枝率,分析辐照剂量及气氛对膜接枝率的影响规律,用红外光谱分析膜接枝后官能团的变化,用扫描电镜观察样品的表面形貌;并分析了接枝率对水通量及牛血清白蛋白（BSA）溶液通量的影响。研究结果表明,对浓度为1mol/L的单体丙烯酸,在氮气或空气的氛围下辐照,接枝率随辐照剂量的增加先增大而后降低,并在整个辐照剂量范围内,氮气氛围下辐照的接枝率均高于空气氛围的接枝率。当接枝率较小时,水通量及BSA溶液通量均随接枝率的增大而增大,并当接枝率为11%时,二者同时达到最大值,随着接枝率的进一步增大,其值反而降低。     

苎麻纤维预辐照二步接枝胺化提高染色性研究

通过电子束预辐照将丙烯酸（AA）接枝到苎麻纤维上形成苎麻-g（接枝）-AA,再用乙二胺（EDA）对苎麻-g-AA进行预辐照接枝胺化形成苎麻-g-AA-EDA,讨论了预辐照接枝率和胺化率与单体浓度的关系。在此基础上对改性苎麻纤维进行无盐染色实验,分析了AA接枝率和EDA胺化率对其上染率的影响。结果表明：苎麻纤维通过预辐照成功接上AA,并进一步接枝EDA实现了胺化,且AA的接枝率和EDA的胺化率随单体浓度的增加而增大,当吸收剂量为40 kGy、EDA浓度为35%时,AA接枝率为25%的苎麻-g-AA样品的EDA胺化率可达20.1%;接枝AA后的苎麻纤维上染率降低,且随AA接枝率的增大而减小,当AA接枝率为25.1%时,上染率低至4.2%;胺化后的苎麻-g-AA-EDA纤维上染率较未胺化的苎麻-g-AA纤维的上染率明显提高,上染率随胺化率的增加而增大,AA接枝率约为25%、胺化率为25%的改性苎麻纤维的上染率达49%。     

PE－AA辐射接枝共聚合的反应历程研究

研究了聚乙烯（ＰＥ）与丙烯酸（ＡＡ）、甲基丙烯酸（ＭＡＡ）的接枝共聚反应，探讨了接枝反应过程及特征：单体首先在ＰＥ表面接枝，然后进入内部进行本体接枝。研究表明：表面接枝为动力学控制，本体接技系扩散控制，单体在膜内的扩散与单体极性及聚合物的结晶度等有关     

吡啶基改性纤维状介孔二氧化硅微球的辐射制备及其对U(VI)的吸附性能

首先合成了双键改性的纤维状介孔二氧化硅纳米微球(F-SiO2-K),将其分散在4-乙烯基吡啶(4-vinylpyridine,4-VP)或4-VP的甲醇溶液中,通过共辐射接枝的方法,制备了吡啶基改性纤维状介孔SiO2纳米微球(F-SiO2-VP).热重分析结果表明,聚4-乙烯基吡啶(P(4-VP))在F-SiO2微球上的接枝率随4-VP单体浓度和吸收剂量增加而增加,但随剂量率的增加先增大后减小.将F-SiO2-VP微球分散在含有U(VI)的硝酸溶液中,测定了室温下微球对U(VI)的吸附容量,并对吸附动力学和吸附等温线进行了分析.结果表明,F-SiO2-VP微球对U(VI)的吸附容量与硝酸浓度和P(4-VP)的接枝率有关.当硝酸浓度为5 mol/L,P(4-VP)的接枝率为16%时,对U(VI)的吸附容量最大,达到163 mg/g.该吸附过程符合准二级动力学模型,其吸附热力学则当U(VI)浓度低时符合Freundlich模型,而U(VI)浓度高时符合Langmuir等温吸附模型.     

HDPE预辐照接枝SSS与AA体系的反应动力学研究

采用电子束引发预辐照接枝方法在高密度聚乙烯(HDPE)上接枝丙烯酸(AA)与对苯乙烯磺酸钠(SSS)两种单体,以制备含磺酸和羧酸基团的双功能基阳离子交换膜。研究发现,接枝速率与辐照剂量、单体总浓度及反应温度密切相关。接枝反应的活化能为22．2kJ／mol。傅立叶变换红外光谱(FTIR)测试表明,接枝膜上引入了磺酸基团和羧酸基团。     

The Application of an Advanced Ion Exchange Process to Reprocessing Spent Nuclear Fuels, (I)

In order to develop an advanced ion exchange process for the reprocessing of spent nuclear fuels, a novel anion exchanger, AR-01 with the resin embedded in porous silica beads and benzimidazoles as functional groups has been manufactured. Adsorption behavior of various fission product elements (FPs) and uranium in nitric acid medium were investigated experimentally using this anion exchanger. Separation performance of FPs from U(VI) in simulated spent fuel solutions was demonstrated by column chromatography utilizing dilute HNO₃ and thiourea as eluents.

Most FPs such as Cs(I), Sr(II), Mo(VI), Rh(III) and trivalent rare earths showed negligibly slight adsorption and could be separated from U(VI) satisfactorily. Cerium(IV) was strongly adsorbed, but was gradually reduced to non-adsorptive Ce(III) by the anion exchanger. Zirconium(IV) presented weak adsorption and its a part mixed with U(VI) in the column experiments. Ruthenium(III) exhibited quite strong adsorption in a broad HNO₃ concentration range as the form of anionic nitrosylnitrato-complexes, its most amount mixed with U(VI). Palladium(II) showed significantly strong adsorption probably due to complexes formation with the anion exchanger. The adsorbed Pd(II) was effectively eluted out by thiourea and separated from U(VI) and other FPs completely.     

电子束引发双功能基阳离子交换膜的制备研究

在所有的离子交换膜中,最引人注目的当数20世纪70年代已商品化的Nation系列膜。具有磺酸功能基的Nation膜电阻低,但用在氯碱工业时电流效率低。1974年Seko发明了全氟羧酸阳离子交换膜,使电流效率有实质性提高,并推动了复合膜的发展。复合膜具有磺酸膜的低电阻性能和羧酸膜的高电流效率。本工作采用辐射接枝法制备含羧酸基团和磺酸基团的双功能基阳离子交换膜,目的主要是以低成本且简单可行的辐射接枝法代替共聚法,制备稳定性好、低电阻、高电流效率的阳离子交换膜。     

Effect of chemical structure of monoamide resins on adsorptivity to uranium(VI) in nitric acid media

For the development of resins with selectivity for uranium(VI) in nitric acid media, some silica-supported monoamide resins with different chemical structures have been newly synthesized and the adsorptivities to U(VI) in HNO₃ have been examined based on our previous results that the chemical structure of monoamide resins might largely affect their adsorptivities to U(VI). The resin consisting of N-vinyl-2-pyrrolidone was found to show relatively strong adsorptivity to U(VI) in the wide concentration range of HNO₃ and little dependence on them. On the other hand, the adsorptivity to U(VI) of the resin with methylacetamide showed dependence on HNO₃ concentrations such as dimethylacrylamide (DMAA) resins which were previously studied, whereas the affinity to U(VI) was smaller than those of DMAA resins. According to the probable adsorption mechanism of U(VI) onto monoamide resins that two oxygen atoms of the two amide groups coordinate to U(VI), the adsorption data suggest that the adsorptivity of monoamide resins is strongly affected by the ‘chelating effect’, namely there are some optimum numbers of the atoms participating in the chelating formation.     

Proton exchange membranes prepared by radiation-induced graft copolymerization from binary monomer mixtures onto poly(tetrafluoroethylene-co-hexafluoropropylene) film

Sulfonic acid proton exchange membranes based on a poly(tetrafluoroethylene-co-hexafluoropropylene) film were synthesized through the single-step graft copolymerization of sodium styrenesulfonate and acrylic acid monomers from binary monomer aqueous solutions using the electron beam pre-irradiation method in air. The effects of the various polymerization parameters (absorbed dose, reaction time, and monomer ratio) on the degree of grafting were studied.A correlation between the degree of grafting and some of the physical-chemical properties (water uptake and ion-exchange capacity) of the synthesized copolymers was established. The distribution of the sulfonic acid groups was investigated across the thickness of several membranes in order to gain a better understanding of the graft copolymerization process from binary monomer aqueous solutions onto the fluorinated film and to synthesize membranes with optimal physical-chemical properties.     

羟基磷灰石辐射接枝甲基丙烯酸甲酯反应的研究

研究了羟基磷灰石在空气中预辐照法接枝甲基丙烯酸甲酯（ＭＭＡ）反应的接枝剂量、单体浓试、接枝温度及无机酸对接枝体系的影响。结果表明，接枝率是由动力学条件控制的，经过恰当的条件选择，可以获得较高的接枝率。对接枝物进行重量法、灼烧法、扫描电镜及红外光谱研究，从不同的侧面证实ＭＭＡ已通过化学键接枝在羟基磷灰石上。表明用辐射引发无机材料接枝有机单体，改善无机－有机复合材料界面，制备生物医学材料的方法是可行的     

One step graft copolymerization of acrylic acid and sodium styrene sulfonate onto high－density polyethylene film by preirradiation method

High-density polyethylene(HDPE)films were irradiated by ^60Co gamma ray with a dose of 100kGy in air and then immersed in aqueous solution of acrylic acid(AA) and sodium styrene sulfonate(SSS) at different temperature.The effects of grafting conditions such as temperature,reaction time ,Mohr‘s salt concentration,and total concentration of monomer on grafting yield were studied.Both grafting yield of AA and SSS onto HDPE respectively increases with total concentration of monomer on grafting yield were studied.Both grafting yield of AA and SSS onto HDPE respectively increases with total concentration of monomers.The highest grafting yield was observed at 3mol/L monomers where the grafted PE swelled to the largest extent in the monomers mixture.The grafting yield increases with reaction time and then levels off.At higher temperature,the grafting yield decreases with Mohr‘s salt concentration,but increases at low temperature when Mohr‘s salt concentration is 0.083%.Which can be interpreted that in the presence of Fe^2 diperoxides and hydroperoxides may decompose at low temperature to form radical which can initiate the grafting.The physical and chemical properties of grafting films were also investigated.     

A study on selective precipitation of U(VI) by hydrophilic cyclic urea derivatives for development of a reprocessing system based on precipitation method

Selective precipitation ability of 2-imidazolidone (EU) and tetrahydro-2-pyrimidinone (PU) for U(VI) species in HNO₃ solutions containing U(VI), U(IV) (simulant of Pu(IV)), and simulated fission products (FPs) was investigated. As a result, it was found that these compounds precipitate almost quantitatively U(VI) as UO₂(NO₃)₂L₂ (L = EU, PU) from 3.0 M HNO₃ solution. In contrast, these urea derivatives form neither solid precipitates nor oily products with U(IV) in HNO₃ solutions containing only U(IV) species and even in U(VI)–U(IV) admixture system. Therefore, the separation of U(VI) from U(IV) was demonstrated to be achieved in use of EU and PU. Furthermore, EU and PU are capable to remove most of simulated FPs[Sr(II), Ru(III), Rh(III), Re(VII) La(III), Ce(III), Pr(III), Nd(III), and Sm(III)] from U(VI) to give their decontamination factors (DFs) higher than 100, while those values of Zr(IV), Mo(VI), Pd(II), and Ba(II) are necessary to be improved in both systems. From these results, it is expected that EU and PU are the promising precipitants for selective separation of U(VI) from HNO₃ solutions dissolving spent FBR fuels.     

聚乙烯辐照接枝体系改变pH对接枝率的影响

采用γ射线辐照引发接枝的方法，在高密度聚乙烯（HDPE）上接枝丙烯酸（AA）和对接枝苯乙烯磺酸钠（SSS），制备了一种含羧酸基团和磺酸基团的阳离子交换膜，详细研究了反应体系在不同pH值下的接枝率变化规律。实验表明，在共辐照接枝方法中，当AA与SSS一步法接枝HDPE或接枝上AA的HDPE膜再共辐照接枝SSS时，总接枝率（Gt）及对苯乙烯磺酸钠的接枝率（Gs）随体系的pH的降低而升高，在预辐照一步法接枝中，Gt与Gs随体系pH的降低先升高后又有所降低，综合分析认为，改变pH值使体系粘度发生变化，从而影响了单体向基体的扩散速率。     

Low-Temperature Partitioning of Plutonium with High U(VI)-Loading for Fuel Reprocessing

Measurement of the distribution ratios of Pu(IV), U(VI) and HNO₃ at low temperatures and its treatment with DIST code revealed that a high U (VI)-loading of 30% TBP in n-dodecane splits Pu(IV) down to the aqueous phase more strongly than do at 25°C. Based on these findings, flowsheet conditions to separate Pu(IV) from U(VI) were investigated with EXTRA.M code including the distribution equations obtained above. And tentative flowsheets for non-reductive Pu-splitting process at a temperature of 5°C were proposed for fuel reprocessing mainly based on the effects of U (VI)-loading in the solvent and temperature on distribution ratios of Pu(IV) and U(VI). Distribution ratios of the fission products, Zr, Nb, Ru and Ce were also measured to assess their decontamination from U or Pu products in the above process. Finally behavior of Np, in the proposed partitioning process was discussed by analysis with EXTRA. M code and a redox reaction model.