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Li D.,Lanzhou University | Li D.,Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization | Chang X.,Lanzhou University | Chang X.,Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization | And 8 more authors.
Talanta | Year: 2011

A new material has been synthesized using dry process to activate bentonite followed by N-(2-hydroxyethyl) ethylenediamine connecting chlorosilane coupling agent. The synthesized new material was characterized by elemental analysis, FT-IR and thermogravimetry which proved that bentonite was successfully modified. The most interesting trait of the new material was its selective adsorption for rare earth elements. A variety of conditions of the new material were investigated for adsorption. The optimal conditions were determined with respect to pH and shaking time. Samarium (Sm) was quantitatively adsorbed at pH 4 and shaking time of 2 min onto the new material. Under these conditions the maximum static adsorption capacity of Sm(III) was found to be 17.7 mg g -1. The adsorbed Sm(III) ion were quantitatively eluted by 2.0 mL 0.1 mol L-1 HCl and 5% CS (NH2)2 solution. According to IUPAC definition, the detection limit (3σ) of this method was 0.60 ng mL-1. The relative standard deviation (RSD) under optimum conditions was less than 3% (n = 8). The new material also was applied for the preconcentration of trace Sm(III) in environmental samples with satisfactory results.© 2010 Elsevier B.V. All rights reserved. Source


Chai X.,Lanzhou University | Chai X.,Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization | Chang X.,Lanzhou University | Chang X.,Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization | And 8 more authors.
Talanta | Year: 2010

In this work, a new 2-(2-oxoethyl)hydrazine carbothioamide modified silica gel (SG-OHC) sorbent was prepared and applied for preconcentration of trace mercury(II) prior to the measurement by inductively coupled plasma atomic emission spectrometry (ICP-AES). The optimization of some analytical parameters affecting the adsorption of the analyte such as acidity, shaking time, sample flow rate and volume, eluent condition, and interfering substances were investigated. At pH 3, the maximum static adsorption capacity of Hg(II) onto the SG-OHC was 37.5 mg g-1. The quantitative recovery (>95%) of Hg(II) could be obtained using 2 mL of 0.5 mol L-1 HCl and 1% CS(NH2)2 solution as eluent. Common coexisting substances did not interfere with the separation of mercury(II) under optimal conditions. The detection limit of present method was 0.10 ng mL-1, and the relative standard deviation (RSD) was lower than 4.0% (n = 8). The prepared sorbent was successfully applied for the preconcentration of trace Hg(II) in certified and water samples with satisfactory results. © 2010 Elsevier B.V. Source


Zhang S.,Lanzhou University | Zhang S.,Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization | He Q.,Lanzhou University | He Q.,Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization | And 10 more authors.
Materials Letters | Year: 2011

Luminescence carbon nanoparticles (CNPs) have been prepared by refluxing the combustion soot of kerosene in nitric acid, and this approach can be used for milligram-scale synthesis of water-soluble particles. These fluorescent CNPs were stable in water for more than 3 months without fluorescence decreasing. Diameter of the water-soluble fluorescent CNPs obtained by scanning electron microscope was about 50 nm. In order to improve CNPs' properties, they were modified with thiocarbamide. The effect of adsorption and deposition for metal ions could be measured by inductively couple plasma atomic emission spectrometry. In addition, the responses to pH of thiocarbamide-modified CNPs were different from the responses of CNPs. © 2011 Elsevier B.V. All rights reserved. Source

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