共查询到20条相似文献，搜索用时 15 毫秒
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关于海水中铀(Ⅵ)与水合氧化钛的作用、国内外已有许多报导,内容包括水合氧化钛制备方法的不同对交换铀量的影响,水合氧化钛和海水中铀的基本物理—化学性质的研究及它们在反应过程中物理—化学性质变化规律的研究,海水中铀与水合氧化钛作用机理的研究等等。但对这一反应的动力学研究文献上报导极少,除了在本研究Ⅰ、Ⅱ和Ⅲ中报导的反应机理的研究[1,2]证明反应过程的速率由液膜扩散所控制之外,关于这一离子交换过程的反应级数和活化能的研究却至今未见有文献报导。 相似文献
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The adsorption behaviour for uranium of four kinds of amidoxime resinst RNH, RCH, RAH and RPH in seawater has been investigated. It has been found that all these resins are capable of adsorbing rapidly uranium from U-cnriched seawater with a high uranium uptake.RNH was able to adsorb uranium satisfactorily from natural seawater, and the uranium uptake of RNH with a degree of cross-linking of 3-5 mol % was above 200 μg/g-R (adsorption for 15 days). The uranium uptakes of RCH, RAH and RPH from natural seawater were much lower than the uranium uptake of RNH. The factors which caused the difference between resins RCH, RAH, RPH and resin RNH are discussed. 相似文献
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This article deals with a new method of analysing in seawater, i. e. the uranium is concentrated with an aqueous suspension of basic zinc carbonate, subsequently isolated and determined by extraction-photometric method. In concentrating uranium such factors as stirring time, amount of adsorbent used, acidity of seawater were studied and conditions suitable for analysis were found. This method is simple, accurate and good in reproducibility. It is not necessary to adjust the pH of seawater before analysis. This technique can also be applied to determination of uranium in river or lake. 相似文献
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MECHANISM OF URANIUM ADSORPTION ON AMIDOXIME RESIN 总被引：1，自引：0，他引：1
The mechanism of uranium adsorption from seawater by polyacrylamidoxime resin is investigated by means of the experiments of adsorption isotherm and adsorption rate. The uranium uptake increases with the adsorption temperature and varies with the pH of seawater. Thermochemical and kinetic calculation show that the enthalpy change (△H) and the activation energy (E) of the uranium adsorption are 42.4 42.4 kJ mol-1 and 41.2 kJ mol-1 respectively, indicating that the uranium adsorption on the resin proceeds via a certain complex chemical reaction in which the amidoxime group in the resin chelates uranyl ions. 相似文献
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A procedure is suggested for direct determination of Sr in seawater using diluted seawater sample and background emission correction by FES. The standard deviation for 8 ppm Sr is better then 2 %, and the recovery of the added Sr is 97-105 %. 相似文献
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A method of electrodeposit-PbSO4 precipitation-β counting has been developed for the determination of 210Pb in marine sediments. The chemical yield of lead is 85-90%, coincident with radiochemical yield. The decontamination factors for 90Sr, 106Ru, 137Cs, 60Co, 65Zn, 55+59Fe and 54Mn are greater than 103. The precision is 2.9%. The typical 210Pb profiles of five cores were successfully obtained in the Changjiang Estuary and adjacent continental shelf. The sedimentation rates of the cores from five stations of G8132, G8133.G8134, G8135 and G8139 are 0.72, 0.86, 0.37, 0.33 and 0.42 cm/yr respectively. 相似文献
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1. The adsorption action of basic zinc carbonate adsorbent on uranium in natural seawater can be expressed with the following formula of adsorption isotherm:C=k(U*)n = 8.51× 10-1(U*)0.49,where C is the concentration of uranium on adsorbent; U* is content of uranium in natural seawater employed.2. when the quantity of basic zinc carbonate adsorbent (T) is constant, with the increase of natural seawater quantity through the adsorption column (G), also increased are the adsorption content of uranium of the adsorbent (U), the concentration of uranium on the adsorbent (C) and the concentration of residual uranium (C0*) in natural seawater after adsorbing uranium, while the rate of recovery of uranium (R) is decreased. With the increase of (G) the coefficient of distribution (Kd) decreases to a certain value and then a little rises again. 相似文献
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东海外陆架及钓鱼岛以北海域鱼类、底栖生物的痕量金属测定 总被引：1，自引：0，他引：1
从海洋生物生态学本身的研究,生物体常量,微量元素的测定,前人已作了很多的工作。随着国防、工业及海上交通运输不断高速发展,各种工业废物大量抛入海洋,海洋污染日趋严重。为此,许多海洋学者又从海洋环境保护出发,对各个海域里的生物成分进行了监测,特别对生物体痕量金属的测定已作了大量工作[3-6]。测定的范围是广范的,从大洋到极地,从深海到岸边,而对受污染严重的港湾及河口的生物毒物研究得更多。 相似文献
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DIRECT AND SIMULTANEOUS DETERMINATION OF Zn, Cd, Pb, Cu and Bi IN SEAWATER BY DERIVATIVE-VOLTAMMETRY
吕荣辉 《海洋学报(英文版)》1985,4(4):557-563
This paper suggests direct and simultaneous determinations of the reducible species of Zn, Cd, Pb, Cu and Bi in seawater made by the derivative-differential pulse anodic stripping voltammetry with a hung mercury drop electrode. The influence of Cu on the determination of Zn in this experiment condition has been studied, of which both the accuracy and precision are satisfactory. The procedure of determination is so quick, simple and convenient that the background concentration of these five elements in coastal seawaters can be determined only by adjusting the acidity of seawater to pH 2.5 and by taking 10-minutes plating time. Actual measurement time of these five elements for every sample is approximately 25 min. 相似文献
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海水样品用乙酸乙酯萃取后，萃取液加入乙酸和氧化铬，在１００℃下回流３０ｍｉｎ，再用正己烷萃取，干燥，浓缩，定容后进行色谱测定，方法简便易行，准确度高，该法已用于青岛胶州湾海水中有机氯农药残留量的测定进行验证。 相似文献
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An analytical method is proposed for the direct determination of Cd in seawater by differential pulse anodic stripping voltammetry and the derivative technique with a hanging mercury drop electrode. The process of determination is quick, simple and convenient. The concentration of Cd in seawater is only determined by adjusting the acidity of seawater to pH 2 and by taking three minutes' plating time. Sensitivity of the method is about 1×10-10M, and accuracy of that satisfactory. Relative standard deviation is about 12% when the concentration of Cd in seawater is approximately 0.04 ppb. A good agreement was obtained by a standard curve and a standard addition technique respectively from determining Cd in the same seawater. Actual measurement time per sample is about 10 min. 相似文献
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研究用交流示波极谱测定海水中钾的方法。海水试样用NaOH调节pH约12,加入过量四苯硼化钠标准溶液,用微孔滤膜(或滤纸)过滤沉淀。收集游液,用TI(Ⅰ)标准溶液滴定过量的四苯基硼离子。方法回收率为99.5％。测定结果与四苯硼化钾重量法结果一致。海水中共存离子不干扰测定,并可用于海水及多种盐溶液中钾的测定。本法因其简便、快速、准确而易于推广。 相似文献
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Li Jinxia 《海洋学报(英文版)》1989,8(3):401-408
Isotope dilution mass spectrometry (IDMS) and ultra-clean room approach are successfully used in the determination of Cd, Pb and Zn in seawater and the sample pretreatment of analysis. The precision in the determination of Cd, Pb and Zn in seawater is better than±3% and the limits of detection are 6×10-12, 6×10-11 and 2.4×10-10 respectively. The effects of sample pretreatment such as filtration and acidification on the results of determination of Cd- Pb and Zn in seawater are disscussed. 相似文献
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用自装的BET容量法装置测定了几种粒状钛型吸附剂的比表面及其孔径分布。测定是在常温减压下进行的。结果表明:钛型吸附剂在加铀海水中的吸铀量与样品的比表面及孔径分布有一定的内在联系。这种表面性质的研究对吸附剂的筛选有重要的指导意义。 相似文献
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目前,化学法测定海水中的钙时,锶往往同时被测定,因此,海洋调查中,钙含量也包含了锶。如果能准确地测定锶,就可以使钙镁的结果更加准确。因此,建立一个准确、快速测定海水中锶的方法是很必要的。 通常锶的测定采用火焰光度法,或直接用石墨炉原子吸收光谱法,然而,前者需经离 相似文献