| Summary: | 碩士 === 國立臺灣海洋大學 === 生物科技研究所 === 101 === (1) Selective tellurium nanowire-based sensors for mercury(II) in aqueous solution
We have developed a simple, colorimetric, and label-free tellurium nanowire (Te NW)-based probe for the detection of mercury ions (Hg(II)) in aqueous solution, operating on the principle of strong hybridization and galvanic replacement reaction of Te‒Hg. The Te NWs (length: 920 nm; diameter: 20 nm) reacted with Hg(II) to induce dissolution and aggregation of the Te NWs. As a result, the absorption band of the Te NWs in a solution undergoes a decrease in the presence of Hg(II). Energy-dispersive X-ray spectroscopy and surface-assisted laser desorption/ionization measurements demonstrated the presence of Hg on the Te NWs. The Te NW probe specifically and sensitively detected Hg(II) ions under optimal concentrations of pH, temperature, and sodium dodecyl sulfate (SDS) concentration. When using a mixture of Te NWs (3.0 nM) and SDS (5 M) in 5 mM sodium phosphate (pH 4) at 50 °C, this sensor provides a limit of detection of 0.5 nM for Hg(II) (signal-to-noise ratio of 3) with high selectivity (at least 100 fold over other metal ions). Our approach abrogates the need for complicated chemosensors or sophisticated equipment. This cost-effective sensing system allows the rapid and simple determination of the concentrations of Hg(II) ions in real samples (in this case, river, lake, and tap water samples).
(2) Synthesis of tellurium nanotubes via a green approach for detection and removal of mercury ions
In the present study, we develop a green approach for the preparation of tellurium nanotubes (Te NTs) by a simple fructose-mediated reduction of Te ions in an alkaline aqueous solution. The influence of reaction conditions, including the types of saccharides involved, reaction temperature, and fructose and NaOH concentrations on the size and morphology of Te nanostructures are investigated and the structural evolution with respect to different growth rates are illustrated. It is proposed that a low reduction reaction rate plays a significant role in the controlled growth mechanism of Te NTs. A simple gel-based membrane is also developed for removal and sensing of mercury ions (Hg(II)) in aqueous solutions. An agarose gel is used to trap as-prepared Te NTs, leading to the preparation of a nanocomposite film composed of Te-NTs-modified agarose gel membrane (Te NTs‒AGM) for removing Hg(II) in the solution via the strong hybridization and galvanic replacement reaction of Te‒Hg. The Te NTs‒AGM adsorbent allows effective removal of mercury species spiked in tap, stream, and sea waters with efficiencies greater than 97%. In addition, Te NTs allow for the rapid and simple detection of Hg(II) at concentrations as low as 10 nM. We validate the practicality of the use of Te NTs–AGM in this application through analyses of Hg(II) in tap water, stream water, and sea water samples. The low-cost, effective, and stable Te NTs‒AGM nanocomposite shows great potential for detection and economical removal of Hg(II).
Keyword: Te NWs, Te NTs, Sensors, Mercury ions, Green chemistry
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