Adsorption Characteristics of a Nanodiamond for Oxoacid Anions and Their Application to the Selective Preconcentration of Tungstate in Water Samples
Adsorption Characteristics of a Nanodiamond for Oxoacid Anions and Their Application to the Selective Preconcentration of Tungstate in Water Samples
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DOI：
10.2116/analsci.22.357
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发表时间：
2006-03
影响因子：
1.6
通讯作者：
H. Sakurai;Noboru Ebihara;E. Ōsawa;M. Takahashi;M. Fujinami;K. Oguma
中科院分区：
文献类型：
--
作者：
H. Sakurai;Noboru Ebihara;E. Ōsawa;M. Takahashi;M. Fujinami;K. Oguma
用爆轰法制备了平均粒径为4 nm的纳米金刚石，并对其进行了表征，将其用作水样中钨酸盐的捕收剂。发现纳米金刚石的水溶液在3至10的pH范围内是稳定的。纳米金刚石的凝结可以通过添加电解质溶液来实现。通过元素分析数据和在弱酸性介质中测量的zeta电位，阐明了纳米金刚石的吸附特性归因于其表面的氨基。将纳米金刚石对含氧酸阴离子的独特吸附性能应用于水样中钨酸根的选择性富集。将适量的纳米金刚石加入到pH 5的样品溶液中，并加入氯化钙溶液以聚集纳米金刚石。然后将样品溶液静置2 h并离心。将纳米金刚石转移到膜过滤器上，用稀氯化钙溶液洗涤，并在ICP-AES测量之前通过以下程序中的任一个进行处理：（a）用超声洗涤器将纳米金刚石再分散到稀硝酸中，和（B）在700 ℃下灰化膜过滤器和凝结的纳米金刚石，然后用盐酸和酒石酸处理灰。在0.25ppm水平下，100 ml人工河水中钨酸盐的平均回收率为99%，RSD为2.2%（n = 3）。目前的集中系数为10。
A nanodiamond with a mean particle size of 4 nm, which was prepared by the detonation of a nanodiamond, has been characterized and used as a collector for tungstate in water samples. An aqueous solution of nanodiamond was found to be stable over the pH range from 3 to 10. Coagulation of the nanodiamond could be brought about by adding an electrolyte solution. The adsorption characteristics of nanodiamond have been elucidated to be attributable to amino groups on its surface by the elemental-analysis data and the zeta potential measured in weak acid media. The unique adsorption properties of the nanodiamond for oxoacid anions were applied to a selective preconcentration method for tungstate in water samples. An appropriate amount of nanodiamond was added to a sample solution at pH 5 and a calcium chloride solution was added to aggregate nanodiamond. The sample solution was then allowed to stand for 2 h and centrifuged. The nanodiamond was transferred onto a membrane filter, washed with a diluted calcium chloride solution and treated in advance of an ICP-AES measurement by either of the following procedures: (a) redispersion of the nanodiamond into dilute nitric acid with an ultrasonic washer and (b) ashing of the membrane filter and the coagulated nanodiamond at 700°C, followed by a treatment of the ash with hydrochloric and tartaric acids. The average recovery of tungstate from 100-ml artificial river-water was found to be 99% at the 0.25 ppm level with an RSD of 2.2% (n = 3). The concentration factor at present is 10.