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作者曾报导了用偶氮氯膦I树脂分离富集微量UO_2~(2+)的研究。实验表明,含偶氮氯膦I基团的树脂对UO_2~(2+)有良好的吸附性能,可以从大体积溶液中定量富集微量UO_2~(2+)。为此我们研究了负载有偶氮氯膦I螯合剂的交换树脂的分析特性,并用于富集铀矿废水中微量UO_2~(2+)。实验部分 1.UO_2~(2+)标准溶液:称取一定量乙酸铀溶解于pH_4HAc-NaAc缓冲液中,制取10mg/ml铀标准溶液,临用时再以水稀释至适当浓度。 2.负载偶氮氯膦I树脂制备:称取湿D-290大孔阴离子交换树脂50g,加到含有一定量偶氮氯膦I的溶液中,搅拌,制得含有螯合剂量为75.1μM/g-干树脂的负载树脂(下称负载 相似文献
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环氧基磁性离子交换树脂的合成与表征 总被引:1,自引:0,他引:1
用r—三氧化二铁—二乙烯三胺—双酚A环氧树脂首次合成了环氧基磁性离子交换树脂。实验结果表明,磁性树脂微球尺寸和吸附容量决定于树脂制备过程中的各种因素。一批典型的环氧基磁性树脂平均直径为0.15mm、吸附容量为3.3meq/g—R,磁化率为8.2emu/g—R,在酸性或碱性介质中稳定。实验数据也证实了这是一类优良的螯合树脂,对Zn~(2+)、Cd~(2+)、Hg~(2+)、Co~(2+)、Ni~(2+)、Pb~(2+)和其他二价阳离子有适当的螯合能力。但不吸附碱土金属离子,这和聚多胺树脂相同。 相似文献
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本文根据单晶的X射线衍射及红外光谱法的实验结果,对铀冠醚配合物(DCH18C6·H_3O)_2UO_2Cl_4的约化配分函数比(RPFR)及各有关振动基频的贡献进行了详细的理论计算,从而估计了UO_2~(2+)(H_2O)_5-(DCH18C6·H_3O)_2UO_2Cl_4铀同位素化学交换体系的交换反应平衡常数K_(eq)(即同位素单级分离因子α,在12℃C和29℃下,分别得到α=1.000746和1,000672与实验值1.0010±0.0002和1.0012±0.0004相当接近。通过理论分析表明,铀的配位水在铀与冠醚形成配合物过程中被剥离,对体系的显著同位素效应起了关键作用。 相似文献
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本文证实了在高氯酸溶液中Rh(Ⅳ)主要以Rh(H_2O)_6~(4+)形式存在。研究了Rh(H_2O)_6~(4+)和Ir(H_2O)_6~(4+)在阳离子交换树脂上的行为。测定了两者在聚苯乙烯磺酸型阳离子交换树脂—HCIO_4间的分配比。根据Rh(H_2O)_6~(4+)和Ir(H_2O)_6~(4+)在阳离子交换柱上的洗脱曲线和回收率,讨论了在高氯酸溶液中Rh和Ir分离的可能性。 相似文献
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测定了弱酸性阳离子交换树脂对Eu~(3+)的交换容量(358.2mgEu~(3+)/g树脂),介质pH、温度、吸附时间等因素对吸附的影响。测得吸附速率常数K_(25℃)—1.66×10~(-3)S~(-1)、K_(28℃)—2.06×10~(-3)S~(-1)、K_(32℃)=2.44×10~(-3)S~(-1)。探讨了吸附机理。在不同浓度比范围,吸附过程中树脂功能基与Eu~(3+)的吸附摩尔比,[COOH]/[EU~(3+)],分别近于1、2、3。 相似文献
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用悬浮聚合法,将γ—Fe_2O_3加入苯乙烯和二乙烯苯(DVB)中可制得聚苯乙烯磁性树脂。本文详细研究了各种因素对合成的影响。实验制得一批典型树脂的磁粉含量为12.8%,粒度为80目。磺化后得到磺酸型阳离子交换树脂,其交换容量为3.22mmol/g—R。实验表明,该种磁性树脂有一定的磁化性能,且耐碱性较好。 相似文献
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研究了UO_2~(2+)-F~--5-Br-PADCAP体系的光度特性。结果表明,在pH 6.0~8.0,[F~-]/[UO_2~(2+)]=400~10000(摩尔比)范围内,试剂及配合物的最大吸收波长分别为456nm和580nm,UO_2~(2+)浓度在8~60μg/25ml范围内符合比耳定律,配合物的摩尔吸光系数为7.4×10~4,组成UO_2~(2+):F~-:R=1:3:1。将所确立的方法用于铀矿废水中铀含量的测定,结果令人满意。 相似文献
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二氧化钍(ThO_2)是一种锕系金属氧化物,作为吸附剂是其重要的应用方向之一,但其应用范围还较为有限,有待进一步拓宽。我们研究了水热法合成的多晶ThO_2纳米球在碳酸铀酰铵((NH_4)_4[UO_2(CO_3)_3])溶液中对铀的吸附性能。结果表明,在含有2 mmol/L NH_4HCO_3和20 mmol/L三羟甲基氨基甲烷-HCl的(NH_4)_4[UO_2(CO_3)_3]溶液(pH=8.45)中,ThO_2纳米球对铀的吸附符合准二级动力学吸附模型,在初始铀浓度为20 mg/L时,ThO_2纳米球对铀的吸附容量可以达到6.52 mg/g;ThO_2纳米球对铀的等温吸附符合Freundlich模型。吸附铀后的ThO_2纳米球可通过低浓度的盐酸进行高效洗脱。机理研究表明,在此实验条件下,ThO_2纳米球带负电荷,通过阳离子吸附机理吸附UO_2~(2+),容易受到Ca~(2+)、Cu~(2+)和Ni~(2+)等阳离子的竞争而出现吸附容量下降的情况。本文的研究工作对金属氧化物从弱碱性及中性放射性废液和海水中提取铀具有参考价值。 相似文献
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本文研究了7-碘-8-羟基喹啉-5-磺酸及8-羟基喹啉-5- 磺酸同金属离子形成的配合物在水溶液中被阴离子交换树脂吸附后所表现出来的室温磷光特性. 制作了测定Al^3^+,Ga^3^+,In^3^+,Zr^4^+和Hf^4^+等金属离子的室温磷光传感器.实验结果表明:离子交换树脂增稳的室温磷光对湿气不敏感,选择性高, 可用于发展一类新型的金属离子传感器 相似文献
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Taking soil colloid and hydrated silica (quartz sand) as the experimental material, the comparative study has been made on the kinetics of ion diffusion and ion exchange in charged colloid and charged coarse disperse systems. The results showed that ion exchange kinetics in the two systems conform to the kinetic law of ion diffusion. Besides, through this comparative study on the kinetics of ion exchange and ion diffusion, a method has been advanced theoretically to estimate the quantity of adsorbed ion that is located in the inner of the Helmholtz layer. As far as hydrated silica is concerned , there were about 33 per cent of the total adsorbed quantity of Mg2+that were located in the inner of the Helmholtz layer under the given experimental conditions, bu tfor soil colloid the percentage was only 7.5. 相似文献
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用同位素交换法研究了Eu3+离子在D72和D751树脂内的扩散过程.应用分步孔道扩散方程将粒内有效扩散系数De分解为孔道扩散系数Dp和固相扩散系数Dg,表明该方程可用于描述多孔树脂内的动力学过程.实验表明,De、Dp、Dg均随反应温度的升高而增大.计算了实验条件下的Eu3+的自扩散活化能;D72树脂的Dp和Dg对温度的响应比D751树脂大,其De、Dp、Dg值亦均大于D751树脂;Eu3+在溶液中的自扩散系数Ds>Dp,说明离子在树脂孔道内的自扩散不能完全等同于其在溶液中的自扩散. 相似文献
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消耗型化学发光传感器的研究 总被引:2,自引:0,他引:2
本文首次发展了多种消耗型化学发光传感器, 方法基于发光试剂通过电价键全部固定在阴、阳离子交换树脂上, 在不添加外来发光试剂的情况下, 可直接对待测物进行传感。该类型传感器固定化方法简单, 灵敏度高, 还可通过控制洗脱剂的浓度精确控制发光试剂的释放量, 进而控制固定化试剂柱的使用寿命。所设计的六种类型的传感器均已成功地应用于样品中待测物的测定。 相似文献
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用H^+和NO3^-离子选择电极组成的电池用电势法测定了HNO3-UO2(NO3)2-H2O系统在25°C时的HNO3的平均活度系数, 求得了同时含有^E0和 ^S0-I关系式的Pitzer方程中的两粒子和三粒子作用参数(^s0(0), ^s(1),Ψ)。用Pitzer方程计算了该系统中水的活度, 并用Pitzer方程、Mckay-Perring方法和Harned方程分别计算了系统中HNO3和UO2(NO3)2的平均活度系数。 相似文献
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This study consists of two parts: The first part comprised an experimental determination of the kinetic parameters for the exchange of water between UO2(H2O)5(2+) and bulk water, including an ab initio study at the SCF and MP2 levels of the geometry of UO2(H2O)5(2+), UO2(H2O)4(2+), and UO2(H2O)6(2+) and the thermodynamics of their reactions with water. In the second part we made an experimental study of the rate of water exchange in uranyl complexes and investigated how this might depend on inter- and intramolecular hydrogen bond interactions. The experimental studies, made by using 17O NMR, with Tb3+ as a chemical shift reagent, gave the following kinetic parameters at 25 degrees C: kex = (1.30 +/- 0.05) x 10(6) s(-1); deltaH(not equal to) = 26.1 +/- 1.4 kJ/mol; deltaS(not equal to) = -40 +/- 5J J/(K mol). Additional mechanistic indicators were obtained from the known coordination geometry of U(VI) complexes with unidentate ligands and from the theoretical calculations. A survey of the literature shows that there are no known isolated complexes of UO2(2+) with unidentate ligands which have a coordination number larger than 5. This was corroborated by quantum chemical calculations which showed that the energy gains by binding an additional water to UO2(H2O)4(2+) and UO2(H2O)5(2+) are 29.8 and -2.4 kcal/mol, respectively. A comparison of the change in deltaU for the reactions UO2(H2O)5(2+)--> UO2(H2O)4(2+) + H2O and UO2(H2O)5(2+) + H2O --> UO2(H2O)6(2+) indicates that the thermodynamics favors the second (associative) reaction in gas phase at 0 K, while the thermodynamics of water transfer between the first and second coordination spheres, UO2(H2O)5(2+) --> UO2(H2O)4(H2O)2+ and UO2(H2O)5(H2O)2+ --> UO2(H2O)6(2+), favors the first (dissociative) reaction. The energy difference between the associative and dissociative reactions is small, and solvation has to be included in ab initio models in order to allow quantitative comparisons between experimental data and theory. Theoretical calculations of the activation energy were not possible because of the excessive computing time required. On the basis of theoretical and experimental studies, we suggest that the water exchange in UO2(H2O)5(2+) follows a dissociative interchange mechanism. The rates of exchange of water in UO2(oxalate)F(H2O)2- (and UO2(oxalate)F2(H2O)2- studied previously) are much slower than in the aqua ion, kex = 1.6 x 10(4) s(-1), an effect which we assign to hydrogen bonding involving coordinated water and fluoride. The kinetic parameters for the exchange of water in UO2(H2O)52+ and quenching of photo excited *UO2(H2O)5(2+) are very near the same, indicating similar mechanisms. 相似文献