ICP—AES法测定陶瓷二氧化铀芯块粉末标准物质中铝,钡,钴,钽,钛和钒

随着大型核电事业的发展,对核纯陶瓷二氧化铀芯块的质量控制、质量保证及对测试方法的校准和确认等方面,迫切需要研制核纯陶瓷二氧化铀芯块的杂质标准物质.测定铀及其化合物中痕量杂质元素,需预先将铀与杂质元素分离,国外大多采用萃取法,国内都采用萃取色谱法.所用萃取剂有TBP、TOPO以及TEHP等.本文用我院合成的237季铵萃取树脂进行分离富集,并用ICP-AES法同时测定陶瓷二氧化铀芯块粉末标准物质中铝、钡、钴、钽、钛和钒.     

四丁基脲从硝酸介质中萃取铀(VI)行为的研究

与常用的铀萃取剂磷酸三丁酯(TBP)相比较,酰胺的理化性质类似于TBP,其主要优点是：降解产物一般不影响裂片元素的去污,产物无固体生成,属于“可完全燃烧”萃取剂,可大大减少放射性废物量。本文用非光气法合成了N,N,N’,N’-正四丁基脲(以下简称TBU),并以无毒性的石油醚作稀释剂,其对铀的萃取规律类似于TBP,萃取能力略低于TBP,在各实验条件下均不出现三相,铀的溶剂化数为2。     

离线预富集电感耦合等离子体质谱法测定天然水体中溶解态硅

以Mg(OH)2共沉淀和阳离子交换树脂作为离线预富集方法,建立了天然水体中溶解态硅电感耦合等离子体质谱(ICP-MS)测定方法。实验采用NaOH作为Mg(OH)2沉淀引发剂,以共沉淀方式将溶解态硅元素从天然水体中分离富集,再利用阳离子交换树脂将基体Mg2 清除,并对洗脱液流速、共沉淀碱度等条件进行优化选择。结果显示:Mg(OH)2共沉淀步骤可定量回收溶解态硅,控制溶液通过阳离子交换树脂的速率可将硅元素与基体Mg2 完全分离而不会造成损失。不同基体的水样的加标回收率为99%~105%,方法检出限为4.5μg/L(3S,n=8),方法精密度RSD小于3%。     

植物样品中低水平铀同位素分析

建立了一种植物样品中痕量铀同位素(~(238)U、~(235)U和~(234)U)的分析方法。通过高温灰化去除植物样品中有机质,采用混合酸消解样品灰分,应用UTEVA萃取色谱分离和纯化铀。化学分离过程中铀的回收率达94%,对Na、K、Ca等基体和干扰元素的去除率超过99%。用高灵敏度ICP-MS/MS同时测定了3种天然铀同位素含量,对~(238)U、~(235)U、~(234)U的检出限分别为3.05、0.34和0.04 pg/g,其中对~(238)U和~(235)U的检出限比文献报道值低1个数量级。对小麦粉标准参考物质中~(238)U的分析结果与参考值吻合,表明本分析方法可靠。将本方法应用于中国西安地区植物样品中铀同位素的分析,结果表明,该地区植物中铀含量和铀同位素比值处于天然水平,未发现人为铀污染。这是中国植物样品中3种天然铀同位素水平的首次调查。     

电感耦合等离子体质谱法测定磷酸钡激光玻璃中超痕量铜

将高纯HF-HNO3组合试剂与高纯PFA低压密闭消解罐建立了针对目标高温烧结体的简洁、快速、低本底湿法样品处理流程。系统优化了组合消解试剂的用量和配比、样品消解温度和消解时间等因素,实现了在150℃消解温度时1.7 m L的总试剂消耗量下样品完全分解总耗时小于1 h,且无需对样品破碎至细颗粒,大大降低了样品制备中的玷污风险。以水杨醛肟类作萃取剂,建立了高效液液萃取分离富集法。以5 m L15%的萃取剂浓度在0.5%HNO3的萃取酸度和20%HNO3反萃取酸浓度下,实现了99.999%的基体分离效率,Cu2+富集10倍。优化了电感耦合等离子体质谱(ICP-MS)测定参数,在840 W低功率和低样品提取量时实现20%HNO3酸度下铜的高信背比检测,全流程方法检出限2.5 ng/g,平行测定RSD(n=6)为3.3%,加标回收率94.3%。基于所建立的方法实现了实际样品的准确测定,得出铜含量与激光能量衰减实验结果线性相关的结果。     

磷钇精矿中少量铀和钍的测定

矿石中少量铀和钍一般采用分别比色测定的方法,但同时测定铀、钍显得操作冗长。本文在前人工作基础上,采用三辛基氧膦(TOPO)作为萃取剂,在2N硝酸介质中同时萃取铀和钍,使之与大量稀土和铁等伴生元素分离。此时,锆也被萃取,并严重干扰钍的测定,但可借助磷钇矿中大量磷酸根,在浓度大的酸溶液中使锆成磷酸锆沉淀而除去。铀钍萃取液用乙醇使之与水互溶,以常用的显色剂直接进行分光测定。本法与其它方法对照,结果吻合,相对标准偏差不超过5%。方法简便、快速。试剂:缓冲液—200毫升三乙醇胺与600毫升水混匀,用高氯酸调至pH8～8.3,加水至1升;混合掩蔽剂—取5克氟化钠,34.6克CyDTA及40克磺     

N,N,N′,N′-四丁基丙二酰胺萃取Tb(Ⅲ)的研究

取代酰胺类萃取剂因其易合成、分解产物易除去而不影响萃取工艺流程等优点 ,在核燃料后处理方面显示出很好的应用前景。国内外在该类萃取剂萃取铀 (Ⅵ )、钍 (Ⅳ )以及硝酸的性能研究方面已经做了大量工作[1 ,2 ] ,但对高放废液中共存稀土元素的萃取研究报道较少[3] 。本文报道Ｎ ,Ｎ ,Ｎ′ ,Ｎ′ 四丁基丙二酰胺 (ＴＢＭＡ)在不同稀释剂中萃取Ｔｂ(Ⅲ )的性能。1　实验1 1　试剂和仪器试剂均为ＡＲ级。ＴＢＭＡ实验室合成 ,减压蒸馏提纯 ,经元素分析、红外光谱等检验产品为目标产物 ,纯度高于 98%。ＦＴＳ 1 65红外光谱仪 (美国Ｂｉｏ Ｒ…     

烷基膦酸功能型离子液体合成、表征及对铀（遇）的萃取性能

以咪唑和吡啶作为阳离子基体,设计合成了3种具有烷基膦酸功能基团的功能型离子液体,利用傅里叶变换红外( FTIR)光谱、核磁共振氢谱(1 H NMR)和元素分析对离子液体的结构进行了确认,测定了离子液体的相转变温度、热稳定性、密度和黏度等物理性能,并对硝酸介质中萃取铀酰离子进行了研究。结果表明,所制备的功能离子液体可同时作为稀释剂和萃取剂,在室温环境下实现对铀(Ⅵ)的萃取,萃取率可达到90%以上。     

铜、钴、镍同时分离工艺的研究

稀土体系三种元素同时分离的工艺最近已有发表,但非稀土方面的工作尚未见报导.对Cu、Co、Ni三种元素,通常是将Cu、Co作为一个组份与Ni分离.本工作对组成为Cu:Co:Ni=1:1:1的水相合成料液设计了两种工艺,进行了串级实验,实现了该三种元素的同时分离, 串级实验以HEH(EHP)作萃取剂,煤油为稀释剂,其它试剂均用分析纯.     

烷基膦酸功能型离子液体合成、表征及对铀(Ⅵ)的萃取性能

以咪唑和吡啶作为阳离子基体,设计合成了3种具有烷基膦酸功能基团的功能型离子液体,利用傅里叶变换红外(FTIR)光谱、核磁共振氢谱(1H NMR)和元素分析对离子液体的结构进行了确认,测定了离子液体的相转变温度、热稳定性、密度和黏度等物理性能,并对硝酸介质中萃取铀酰离子进行了研究.结果表明,所制备的功能离子液体可同时作为稀释剂和萃取剂,在室温环境下实现对铀(Ⅵ)的萃取,萃取率可达到90%以上.     

The uranium-Xylidyl Blue I complex and its application in linear sweep polarography

The linear sweep polarographic wave of the uranium-Xylidyl Blue I complex in ethylenediamine-1,10-phenanthroline-hydrochloric acid medium has been studied. The complex, corresponding to UO(2)(XBI)(2-)(2) with log beta' = 9.09 (by polarography), 8.81 (by spectrophotometry), is strongly adsorbed on the surface of the mercury electrode. The polarographic wave is attributed to the reduction of Xylidyl Blue I in the complex. The method is very sensitive with a detection limit of 3 x 10(-8)M. The wave height is proportional to the concentration of uranium over the range 8 x 10(-8)-7 x 10(-6)M. Solvent extraction is used to separate possible interferences. The recommended procedure has been applied to the determination of trace amounts of uranium in ores.     

Spectrophotometric determination of uranium using chromotrope 2R complexes

A simple, fast and reliable spectrophotometric method for the determination and microextraction of trace amounts of uranium using chromotrope 2R as a chelating agent and 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid (IL) was used as an extractant solvent. Influence variables such as pH, volume of ligand and IL were inspected by full factorial design. In the view of Pareto chart a contour plot was studied to examine the significant variables and their interactions. The detection limit and the preconcentration factor were found to be 0.87 and 50 μg L^?1, respectively. The developed method was successfully applied to ore samples.     

色谱分离ICP-AES法测定高纯度八氧化三铀中的13种微量杂质

采用磷酸三丁酯（TBP）萃淋树脂色层分离铀，用电感耦合等离子体-原子发射光谱法测定分离后的离纯度铀氧化物的杂质元素Al、Ca、Cr、Cu、Fu、Mn、Mo、Ni、P、Ti、V、Zn、Zr，除Al、Fe、Mo外的其余10种元素的测定结果符合标准物质定值的要求。     

Progress in neutron activation analysis for uranium

A new type of extractant, sym-dibenzo-16-crown-5-oxyhydroxamic acid (HL) is introduced. The extractions of UO22+, Na+, K+, Sr2+, Ba2+ and Br- were studied with HL in chloroform. The results obtained show that UO22+ can be quantitatively extracted at pH values above 5, whereas the extractions of K+, Na+, Sr2+, Ba2+ and Br- are negligible in the pH range of 2 - 7. The dependence of the distribution ratio of U(VI) on both the concentration of the HL and pH are linear, and they have the same slope of 2. This suggests that U(VI) appears to form a 1:2 complex with ligand. Uranium(VI) can be selectively separated and concentrated from interfering elements such as Na, K, Sr and Br by solvent extraction with HL under specific conditions. The recovery of uranium is nearly 100% and the radionudear purity of uranium is greater than 99.99%. Therefore, neutron activation analysis has greatly improved the sensitivity and accuracy for the detection of trace uranium from seawater.     

Determination of trace uranyl ions in aquatic medium by a useful and simple method

Determination of trace uranyl ions was performed by using mixed micellar system and spectrophotometric determination. The method is based on cloud point extraction of uranyl ions after formation of an ion-association complex in the presence of Celestine Blue and sodium dodecyl sulfate. Then, the formed complex was extracted to non-ionic surfactant phase of Triton X-114 at pH 8.0. The optimal extraction and reaction conditions (e.g. concentrations and types of surfactants, concentration of complex forming agent, incubation conditions) were studied and analytical characteristics of the method (e.g. limit of detection, linear range, pre-concentration factor) were obtained by experimental studies. Linearity was obeyed in the range of 50–1,500 ng mL^?1 for uranium(VI) ion and the detection limit of is 14.20 ng mL^?1. The interference effects of common ions were also tested and validation studies were performed by using recovery test. The method was applied to the determination of uranium(VI) in several real samples.     

Poly(amidoxime)-reduced graphene oxide composites as adsorbents for the enrichment of uranium from seawater

The development of efficient materials for high extraction of uranium(UO22+) from seawater is critical for nuclear energy. Poly(amidoxime)-reduced graphene oxide(PAO/rGO) composites with excellent adsorption capability for UO22+ were synthesized by in situ polymerization of acrylonitrile monomers on GO surfaces, followed by amidoximation treatment with hydroxylamine. The adsorption capacities of PAO/rGO composites for UO22+ reached as high as 872 mg/g at pH 4.0. The excellent tolerance of these composites for high salinity and their regeneration-reuse properties can be applied in the nuclear-fuel industry by high extraction of trace UO22+ ions from seawater.     

Detection of uranium in industrial and mines samples by microwave plasma torch mass spectrometry

Microwave plasma torch (MPT), traditionally used as the light source for atomic emission spectrophotometry, has been employed as the ambient ionization source for sensitive detection of uranium in various ground water samples with widely available ion trap mass spectrometer. In the full‐scan mass spectra obtained in the negative ion detection mode, uranium signal was featured by the uranyl nitrate complexes (e.g. [UO₂(NO₃)₃]^?), which yielded characteristic fragments in the tandem mass spectrometry experiments, allowing confident detection of trace uranium in water samples without sample pretreatment. Under the optimal experimental conditions, the calibration curves were linearly responded within the concentration levels ranged in 10–1000 µg·l^?1, with the limit of detection (LOD) of 31.03 ng·l^?1. The relative standard deviations (RSD) values were 2.1–5.8% for the given samples at 100 µg·l^?1. The newly established method has been applied to direct detection of uranium in practical mine water samples, providing reasonable recoveries 90.94–112.36% for all the samples tested. The analysis of a single sample was completed within 30 s, showing a promising potential of the method for sensitive detection of trace uranium with improved throughput. Copyright © 2016 John Wiley & Sons, Ltd.     

Fluorescence determination of trace amounts of uranium(VI) in various materials by a repetitive laser technique

A laser-induced fluorescence method (LFM) is described for determination of trace amounts of uranium(VI), with a detection limit of 4 x 10(-11) g/ml. A repetitive pulsed laser, time discrimination and an averaging technique are used. The optimum time discrimination is obtained when the uranyl ion is complexed with phosphoric acid or sodium polysilicate. LFM does not need a preconcentration step or separation of uranium from interfering elements. The time needed for analysis is only 1-2 min.     

Determinations of uranium at trace and subtrace levels in organic substances by wet ashing-Arsenazo III method

A method was developed for the determination of trace and subtrace amounts of uranium in organic substances used during the industrial process of nuclear fuel production. The method is based on decomposing 50 g of the sample by wet ashing with 25 g conc. sulfuric acid. The residue from the ashing process was ignited at 525 °C to remove all carbonaceous materials. The residue was boiled with 10 ml of 11 nitric acid. The resulting solutions was analyzed for uranium concentration using a modification of the arsenazo III method which allows for uranium determination after separating it by TBP extraction from all the interfering elements. The proposed method proved to be sensitive (detection limit: 15 ppb). The relative standard deviation of the method for a sample containing 200 ppb uranium is 5%. The dynamic range of the method is wide, since the method is applicable. for trace and subtrace levels of uranium in organic substances.     

Detection of uranium with a wireless sensing method by using salophen as receptor and magnetic nanoparticles as signal-amplifying tags

A new wireless sensing method for the detection of uranium in water samples has been reported in this paper. The method is based on a sandwich-type detection strategy. Salophen, a tetradentate ligand of uranyl ion, was immobilized on the surface of the polyurethane-protected magnetoelastic sensor as receptor for the capture of uranyl ion. The phosphorylated polyvinyl alcohol coated magnetic Fe₃O₄ nanoparticles were used as signal-amplifying tags of uranyl ion. In a procedure of determining uranium, firstly uranyl ion in sample solution was captured on the sensor surface. Then the captured uranyl bound the nanoparticle through its coordination with the phosphate group. The amount of uranium was detected through the measure of the resonance frequency shift caused by the enhanced mass loading on the sensor surface. A linear range was found to be 0.2–20.0 μg/L under optimal conditions with a detection limit of 0.11 μg/L. The method has been applied to determine uranium in environmental water samples with the relative standard deviations of 2.1–3.6 % and the recoveries of 98.0–101.5 %. The present technique is one of the most suitable techniques for assay of uranium at trace level in environmental water samples collected from different sources.