Entity

Time filter

Source Type


Yang Y.,Kunming University of Science and Technology | Li Z.,Kunming University of Science and Technology | Zhen W.,Kunming Fruit Business and Economics Co. | Tai Z.,Kunming University of Science and Technology | And 2 more authors.
Asian Journal of Chemistry | Year: 2013

A simple and practical preconcentration method was developed for the cloud point extraction of gold and silver. The method is based on the formation of hydrophobic complexes of gold and silver ions with sodium diethyldithiocarbamate (Na-DDTC) and Dow Corning DC- 193 was added as a non-ionic surfactant. The phase diagrams of the binary system, water-surfactant (DC-193) and the ternary system, water-surfactant-fatty acids (nonanoic acid), were determined. Under the optimal conditions, the calibration curves were linear in the range of 10-500 μg/L and 10-800 μg/L with the detection limits of 3.4 μg/L and 2.7 μg/L for gold and silver, respectively. The enrichment factors are 25 and 20 for gold and silver, respectively. The relative standard deviations are 3.6 % for gold and 3.4 % for silver (n = 11). The method was successfully applied to the determination of gold and silver in water samples. Source


Lian Y.,Kunming University of Science and Technology | Zhen W.,Kunming Fruit Business and Economics Co. | Tai Z.,Kunming University of Science and Technology | Yang Y.,Kunming University of Science and Technology | And 2 more authors.
Rare Metals | Year: 2012

Cloud point extraction (CPE) with Tergitol TMN-6 was applied for the extraction of trace amounts of palladium (Pd(II)), platinum (Pt(IV)), and gold (Au(III)) in the soil of industrial sewage. Ammonium pyrolysine dithiocarbamate (APDC) was adopted as the chelating agent prior to CPE and then was detected by atomic absorption spectrometry (AAS). Different parameters such as the concentration of surfactants, chelating agent and salt, sample pH, equilibration temperature and time, centrifugation time and rates, and the effect of foreign ions were studied. Under optimum conditions, the low limits of detections are 1.4, 2.8 and 1.2 ng·ml-1 and the enrichment factors are 21, 12, and 24 for Pd(II), Pt(IV), and Au(III), respectively. The relative standard deviations vary from 0.6% to 1.0% (n=11). All correlation coefficients of the calibration curves are >0.9960. The proposed method was successfully applied for the determination of Pd(II), Pt(IV), and Au(III) in the real soil of industrial sewage samples. © The Nonferrous Metals Society of China and Springer-Verlag Berlin Heidelberg 2012. Source


Song J.,Kunming University of Science and Technology | Zhen W.,Kunming University of Science and Technology | Zhen W.,Kunming Fruit Business and Economics Co. | Li Z.,Kunming University of Science and Technology | And 2 more authors.
Water Science and Technology | Year: 2012

A novel method for the determination of nickel was established by ultrasonic-assisted cloud point extraction (UA-CPE) prior to flame atomic absorption spectrometry (FAAS) analysis. The nickel reacted with N,N′-bis(salicylidene)-1,2-ethanediamine (BSE) to form hydrophobic chelates, which were extracted into the micelles of alpha-[3,5-dimethyl-1-(2- methylpropyl)hexyl]-omega-poly(oxy-2-ethanediyl) (Tergitol TMN-6). Tergitol TMN-6 was used as green nonionic surfactant. BSE was synthesized and checked by nuclear magnetic resonance (NMR) spectra. The phase diagrams of the binary system, water-surfactant (Tergitol TMN-6), and the ternary systems, water-surfactant-salt, were determined. The effects of experimental conditions including pH of sample solution, concentration of chelating agent and surfactant, ultrasonic power, equilibration temperature and incubation time were evaluated in order to enhance sensitivity of the method. Under the optimal conditions, the calibration graph was linear in the range of 10-500 μg L -1. The values obtained for the limit of detection and enrichment factor were 1.0 μg L-1 and 30, respectively. The method was successfully applied to the analysis of nickel in water samples. © IWA Publishing 2012. Source

Discover hidden collaborations