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首页> 外文期刊>Analytical Sciences >Study on Multi-walled Carbon Nanotubes On-line Separation/ Preconcentration of Chromium(III) and Chromium Speciation
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Study on Multi-walled Carbon Nanotubes On-line Separation/ Preconcentration of Chromium(III) and Chromium Speciation

机译：多壁碳纳米管在线分离/富集铬（III）和铬形态的研究

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Using multi-walled carbon nanotubes (MWCNTs) as an adsorbent has been established for the on-line separation and preconcentration Cr(III) and chromium speciation. The surface functional groups and negative charges of MWCNTs are beneficial to the adsorption of Cr(III). At pH 3.0 – 6.0, a discrimination of Cr(III) and Cr(VI) is achieved on the MWCNTs surface. Cr(III) ions are adsorbed onto the oxidized MWCNTs surface, while Cr(VI) has no affinity for the MWCNTs. The adsorbed Cr(III) is quantitatively eluted by 10% (v/v) nitric acid with detection by flame atomic absorption spectrometry. By loading a 6.0-ml sample solution, an enrichment factor of 22, a detection limit (3σ) of 1.15 μg l~(?1) and a precision of 1.7% RSD at the 30 μg l~(?1) level (n = 7) are achieved for Cr(III) within a linear range of 5 – 200 μg l~(?1) (r = 0.9994). After Cr(VI) has been reduced to Cr(III) with hydroxylamine hydrochloride, the total amount of chromium is obtained, and the content of Cr(VI) is given by subtraction. The procedure is validated by analyzing chromium in a certified reference material, and is further applied for the speciation of chromium in electroplating wastewater samples with satisfactory results.
机译：已经建立了使用多壁碳纳米管（MWCNT）作为吸附剂的在线分离和预富集Cr（III）和铬形态的方法。 MWCNT的表面官能团和负电荷有利于Cr（III）的吸附。在pH 3.0 – 6.0时，在多壁碳纳米管表面可以识别出三价铬和六价铬。 Cr（III）离子吸附在氧化的MWCNTs表面，而Cr（VI）对MWCNT没有亲和力。吸附的Cr（III）用10％（v / v）硝酸进行定量洗脱，并通过火焰原子吸收光谱法进行检测。通过加载6.0 ml的样品溶液，富集系数为22，检测限（3σ）为1.15μgl〜（？1），在30μgl〜（？1）水平下的精密度为1.7％（< Cr（III）在5 – 200μgl〜（？1）的线性范围内（r = 0.9994）达到i> n = 7）。用盐酸羟胺将Cr（VI）还原为Cr（III）后，获得了铬的总量，并通过减法给出了Cr（VI）的含量。该方法通过分析认证参考材料中的铬而得到验证，并进一步用于电镀废水样品中铬的形态分析，结果令人满意。

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