用新型的二氧化硅改性的热还原石墨烯为吸附剂采用固相萃取法和紫外可见分光光度法痕量测定环境水样中的铬vi含量.ppt
《用新型的二氧化硅改性的热还原石墨烯为吸附剂采用固相萃取法和紫外可见分光光度法痕量测定环境水样中的铬vi含量.ppt》由会员分享,可在线阅读,更多相关《用新型的二氧化硅改性的热还原石墨烯为吸附剂采用固相萃取法和紫外可见分光光度法痕量测定环境水样中的铬vi含量.ppt(11页珍藏版)》请在三一文库上搜索。
1、Trace determination of chromium(VI) in environmental water samples using innovative thermally reduced graphene (TRG) modified SiO2 adsorbent for solid phase extraction and UVvis spectrophotometry 用新型的二氧化硅改性的热还原石墨烯为吸附剂采用固相萃取法和紫外可见分光光度法痕量测定环境水样中的铬(VI)含量,姓名:汤娟 专业:化学工程,Abstract,An innovative thermally r
2、educed graphene (TRG) modified silica-supported 3-aminopropyltriethoxysilane (SiO2-APTES) composite was synthesized and characterized using Fourier transform-infrared spectroscopy (FT-IR) and scanning electron microscopy SEM techniques. The adsorbent was then used in the solid phase extraction (SPE)
3、 of Cr (VI) as the Cr (VI)-diphenylcarbazide (DPC) complex with the subsequent measurement by UVvis spectrophotometry. The adsorbent surface was activated by addingsodium dodecyl sulfate (SDS) to the sample solution. The effect of the main experimental parameters such as type and volume of the extra
4、ction solvent, pH, dosage of DPC, SDS, the adsorbent, time of the extraction, and salt concentration on the extraction efficiency were investigated and optimized. A linear dynamic range of 1.3-40 ng mL-1 with a satisfactory determination coefficient (R2) of 0.9930 was obtained. A detection limit of
5、0.4 ng mL-1 Cr (VI) was attained when a sample volume of 25 mL was used. Intraday and inter-day precisions were obtained equal to 2.3% and 7.9%, respectively. The enrichment factor (EF) was calculated to be equal to 167. The technique was applied successfully to the determination of Cr (VI) at trace
6、 levels in tap, river, sewage and ground water samples and the relative recoveries of the added chromium were in the range of 92.6109.9%.,Introduction,In recent years, large number of carbon-based nanomaterials including fullerene, carbon nanotubes, graphene and graphene oxide have been investigated
7、 as adsorbent in SPE due to their excellent adsorption capacity, large surface area, ease of surface modification, chemical stability, durability, corrosion resistance,unique mechanical and electrochemical properties. Graphene(G) is a two-dimensional monolayer of carbon atoms that has ultrahigh surf
8、ace area and high chemical stability. Strong vander waals interactions between G sheets reduce its solubility insolvents and consequently reduce the adsorption of organic compounds or metal ions. Graphene oxide (GO) is the oxidized derivative of G which contains oxygen atoms (as epoxy,hydroxyl, and
9、carboxyl groups) on the surface of carbon sheets. Therefore, GO is much more hydrophilic than G and can provide formation of hydrogen bonding or electrostatic interactions with organic compounds or metal ions. In order to use both ultrahigh surface area of G and oxygen containing groups of GO,using
10、thermally reduced GO (TRG) sheets is a good idea. TRG is a single or few-layer oxygen-functionalized graphene sheets which has far less amount of oxygen-containing groups compared to GO and takes the advantages of both G and GO.,In this work, we prepared a novel adsorbent by attaching TRG on silica-
11、supported 3-aminopropyltriethoxysilane (SiO2-APTES)surface, and used for extraction of Cr (VI) in environmental water samples. The selectivity of the adsorbent toward the Cr (VI) species was improved by formation of a Cr (VI)-diphenylcarbazide complex prior to the adsorption. Complex formation betwe
12、en Cr(VI) and DPC is an interesting reaction for spectrophotometric determination of Cr(VI). This reaction has high selectivity for Cr (VI) versus Cr (III). The adsorbent has surface characteristics of graphene and graphene oxide such as large contact surface area and high amounts of polar groups on
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- 新型 二氧化硅 改性 还原 石墨 吸附剂 采用 萃取 紫外 可见 分光光度法 痕量 测定 环境 水样 中的 vi 含量
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