製備金奈米粒子-氧化鋁吸附劑及其在汞物種分析之應用

Synthesis of Gold Nanoparticles-Aluminium Oxide Adsorbents for Analysis of Mercury Species

羅雪怡(Sut-I Lo)

指導教授 ： 張煥宗

國立臺灣大學/理學院/化學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.00988

摘要

本研究開發一種新的複合材料，利用13-nm金奈米粒子(gold nanoparticles；簡稱Au NPs)吸附於活性氧化鋁(50-200 μm，Al2O3)粒子表面製備出奈米複合材料Au NPs─Al2O3，有效應用於水溶液中金屬離子的吸附以及汞物種的移除、濃縮和偵測。研究中比較三種不同的吸附材料：氧化鋁(Al2O3)、金奈米粒子(Au NPs)和金奈米粒子─氧化鋁(Au NPs─Al2O3)對鎘、鈷、鉻、鎳、鉛(Cd2+, Co2+, Cr3+, Ni2+, Pb2+)這五種重金屬離子和汞物種包括無機汞(mercury，Hg2+)、甲基汞(methylmercury，CH3Hg+)、乙基汞(ethylmercury，C2H5Hg+)和苯基汞(phenylmercury，C6H5Hg+)的吸附能力。由研究結果顯示，Au NPs對於Hg2+的親和力(Kd = 0.3 nM；Bmax = 3370 μmol/g Au NP)遠大於Al2O3 (Kd = 52.9 nM；Bmax = 130 μmol/g Al2O3)，Al2O3對於五種金屬離子的親和力(Cd2+：Kd = 4.1 nM；Co2+：Kd = 7.9 nM；Cr3+：Kd = 34.1 nM；Ni2+：Kd = 16.2 nM；Pb2+：Kd = 4.5 nM)遠大於Au NPs (皆無親和力)。而與上述兩種相較，Au NPs─Al2O3複合材料對汞物種(CH3Hg+：Kd = 6.9 nM；C2H5Hg+：Kd = 6.2 nM；C6H5Hg+：Kd = 7.9 nM；Hg+：Kd = 19.2 nM)和五種金屬離子(Cd2+：Kd = 5.5 nM；Co2+：Kd = 8.1 nM；Cr3+：Kd = 40.5 nM；Ni2+：Kd = 16.9 nM；Pb2+：Kd = 4.6 nM)具較佳之親和力。綜合上述結果，Au NPs─Al2O3有效移除分析樣品中的金屬離子和汞物種，可藉由吸附作用對四種汞離子進行預濃縮後，以感應耦合電漿質譜儀(ICP-MS)進行偵測，可到sub-fM。在真際樣品測量，Au NPs─Al2O3吸附劑可有效移除湖水、自來水和海水中的四種汞離子高達97%。利用Al2O3和Au NPs─Al2O3，我們可對魚肉標準品(DORM-2)中的無機汞和甲基汞分別定量，相信Au NPs─Al2O3吸附材料能廣泛應用於測量工業廢水和生物樣品中的汞。

關鍵字

汞 ； 甲基汞 ； 金奈米粒子 ； 氧化鋁

並列摘要

We report a new and effective adsorbent for removal of metal ions and mercury species. By mixing Au NPs (13 nm in diameter) with aluminum oxide particles (50-200 μm in diameter), Au NPs─Al2O3 adsorbents are easily prepared. Three adsorbents—Al2O3, Au NPs, and Au NPs─Al2O3—have been tested for removal of the metal ions (Cd2+, Co2+, Cr3+, Ni2+, Pb2+) and mercury species [Hg2+, methylmercury (CH3Hg+), ethylmercury (C2H5Hg+), and phenylmercury (C6H5Hg+)]. The Au NPs adsorbent has higher binding affinity toward Hg2+ ions (Kd = 0.3 nM; Bmax = 3370 μmol/g Au NP) than that of Al2O3 adsorbent (Kd = 52.9 nM; Bmax = 130 μmol/g Al2O3). Relative to the individual Al2O3 and Au NPs adsorbents, the Au NPs─Al2O3 adsorbents have higher affinity for mercury species (CH3Hg+: Kd = 6.9 nM; C2H5Hg+: Kd = 6.2 nM; C6H5Hg+: Kd = 7.9 nM; Hg+: Kd = 19.2 nM) and other tested metal ions (Cd2+: Kd = 5.5 nM; Co2+: Kd = 8.1 nM; Cr3+: Kd = 40.5 nM; Ni2+: Kd = 16.9 nM; Pb2+: Kd = 4.6 nM), respectively. The Au NPs─Al2O3 adsorbents provide a synergic effect and thus are effective for removal of most tested metal ions and organic mercury species. After preconcentration of mercury ions by Au NPs─Al2O3 adsorbent, inductively coupled plasma-mass spectrometry (ICP-MS) allows the detection of mercury ions down to sub-fM level in aqueous solution. The Au NPs─Al2O3 adsorbent allows effective removal of mercury species spiked in nature waters (lake water, ground water and sea water), with the efficiencies greater than 97%. We have used sequentially Al2O3 and Au NPs─Al2O3 adsorbents for selective removal of Hg2+ and CH3Hg+ ions from a certified fish sample (DORM-2). The ICP-MS has been applied to determine the concentrations of the preconcentrated Hg2+ and CH3Hg+ ions, with results that are in good agreement with the certified values. The low-cost, effective, and stable Au NPs─Al2O3 adsorbents show great potential for economic use in removal of metal ions and various mercury species.

並列關鍵字

mercury ； methylmercury ； gold nanoparticles ； aluminium oxide

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