Changli Bao

Jilin University, Jilin, Jilin Sheng, China

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Publications (14)30.88 Total impact

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    ABSTRACT: Graphene oxide (GO) was prepared and characterized by Fourier transform infrared spectrometry (FT-IR) and scanning electron micrographs (SEM). Batch adsorption studies were carried out to investigate the adsorption data, including the effects of pH, initial concentration, contact time, and temperature. The adsorption of Au(III), Pd(II), and Pt(IV) was optimum at pH 6.0. The adsorption isotherms all obeyed the Langmuir equation in the case of Au(III), Pd(II), and Pt(IV), and the maximum adsorption capacities were 108.342 mg·g–1, 80.775 mg·g–1, and 71.378 mg·g–1, respectively. The adsorption kinetics of Au(III), Pd(II), and Pt(IV) onto GO followed a pseudosecond-order kinetic model, indicating that the chemical adsorption was the rate-limiting step. Thermodynamic parameters such as Gibbs energy (ΔGo), enthalpy (ΔHo), and entropy (ΔSo) were calculated, indicating that the adsorption were spontaneous, endothermic, and feasible. The desorption studies showed that the best desorption reagents were 0.5 mol·dm–3 thiourea–0.5 mol·dm–3 HCl for Au(III) and 1.0 mol·dm–3 thiourea–0.5 mol·dm–3 HCl for both Pd(II) and Pt(IV).
    Journal of Chemical & Engineering Data 12/2012; 58(2):209–216. · 2.00 Impact Factor
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    ABSTRACT: In this work, graphene oxide (GO) was firstly prepared, following by element analysis. Glutaraldehyde cross-linked chitosan (GCCS) and chitosan/graphene oxide (CSGO) composite with three different amounts of GO (5 wt%, 10 wt% and 15 wt%) were also prepared for the adsorption of Au(III) and Pd(II) in aqueous solution. The properties of the adsorbents were investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and surface area analysis. Batch adsorption studies were carried out. The adsorption of Au(III) and Pd(II) onto CSGO composites was optimum at pH 3.0-5.0 for Au(III) and pH 3.0-4.0 for Pd(II), which was much wider than that of GCCS. The adsorption isotherms obeyed the Langmuir isotherm models for the adsorption of Au(III) and Pd(II). Chitosan with 5 wt% graphene oxide (CSGO(5)) composite had the largest adsorption capacity for Au(III) and Pd(II) compared with the other prepared adsorbents, where the maximum adsorption capacity were 1076.649 mg/g for Au(III) and 216.920 mg/g for Pd(II), respectively. The adsorption kinetics of Au(III) and Pd(II) onto CSGO(5) followed a pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step. Thermodynamic parameters, such as Gibbs energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°), were calculated, showing that the adsorption of Au(III) and Pd(II) onto CSGO(5) were spontaneous, endothermic and feasible. The desorption studies of Au(III) and Pd(II) onto CSGO(5) showed that CSGO(5) can be used repeatedly without significantly changing its adsorption capacity and desorption percentage after 3 cycles. Besides CSGO(5) was successfully applied for the determination and separation of Au(III) and Pd(II) in ore samples.
    Talanta 05/2012; 93:350-7. · 3.50 Impact Factor
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    ABSTRACT: An efficient and environmentally friendly analytical process based on cloud point extraction (CPE) has been developed for the determination of carbamate pesticides and phthalates in vegetables by high performance liquid chromatography (HPLC) separation and ultraviolet detection (UV). The readily biodegradable nonionic surfactant Tergitol 15-S-7 is chosen as extraction solvent. To obtain optimum extraction efficiency, several experimental parameters including surfactant concentration, salt concentration, equilibration temperature, equilibration time, and sample pH are identified. Under the optimum conditions, the linear regression coefficients of the standard curves are greater than 0.9984. The limits of detection for carbaryl, pirimicarb, dimethyl phthalate (DMP), and diethyl phthalate (DEP) are 0.003, 0.015, 0.012, and 0.006 µ g mL, respectively. The intra-day and inter-day relative standard deviations are less than 5.75% and 6.97%. The proposed method has been proven to be an efficient, green, rapid, and inexpensive approach for extraction and determination of target analytes present in vegetable samples.
    Analytical Letters 01/2012; · 0.97 Impact Factor
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    ABSTRACT: 3′-Nitro-4-amino azobenzene modified chitosan has been prepared and characterized by FT-IR. The adsorption data have been investigated including the effects of pH, initial concentration, and contact time by batch method. The adsorption of Pd(II) and Pt(IV) was best in the pH range of 4.0–6.0 for Pd(II) and at pH 3.0 for Pt(IV), where the maximum mass adsorption were (29.33 and 43.10) mg·g–1, respectively. The adsorption isotherms obeyed the Langmuir equation for the adsorption of Pd(II) and Pt(IV). The adsorption kinetic data were fitted with a pseudosecond-order model and an intraparticle diffusion model. The results indicated that the adsorption of Pd(II) and Pt(IV) followed a pseudosecond-order model. The adsorbent shows high affinity for Pd(II) and Pt(IV) in binary systems containing each noble metal ion and other base metal ions. The optimal desorption reagent was 0.20 mol·L–1 thiourea + 0.50 mol·L–1 HCl solution for both Pd(II) and Pt(IV). The method was successfully applied for the determination and separation of Pd(II) and Pt(IV) in ore samples.
    Journal of Chemical & Engineering Data. 10/2011; 56(11).
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    ABSTRACT: In the present study, sec-nonylphenoxy acetic acid (CA100) and its mixtures with four neutral organophosphorus extractants, tri-butyl-phosphate (TBP), 2-ethylhexyl phosphonic acid di-2-ethyl ester (DEHEHP), Cyanex923, and Cyanex925 have been applied to the extraction of rare earths. Results show that all the four mixing systems do not have evident synergistic effects on the extraction of rare earths. The different extraction effects have been considered to the separation of rare earths. The four mixtures may be applied to the separation of yttrium from some certain lanthanoids at proper mole fractions of CA100.
    Russian Journal of Inorganic Chemistry 01/2011; 56(7):1157-1161. · 0.42 Impact Factor
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    ABSTRACT: In this study, a novel method for the determination of nitroanilines in hair dye samples has been developed based on poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction (PMME) and high-performance liquid chromatography (HPLC) analysis. Four nitroanilines, p-nitroaniline (PNAL), m-nitroaniline (MNAL), o-nitroaniline (ONAL), and 2,4-dinitroaniline (DNAL), are studied as representatives. To obtain optimum extraction efficiency, several experimental parameters including sample flow rate, sample volume, sample pH, and eluent flow rate have been investigated. Under the optimal experimental conditions, the linear regression coefficients of the standard curves are greater than 0.9990. The limits of detection for p-nitroaniline, m-nitroaniline, o-nitroaniline, and 2,4-dinitroaniline are 0.012, 0.008, 0.018, and 0.005 μg/mL, respectively. The intraday and interday relative standard deviations are less than 3.1 and 5.4%, respectively. The proposed method is simple, rapid, sensitive, and competent when used for the determination of nitroanilines in hair dye samples and the accuracy is assessed through recovery experiments.
    Journal of Separation Science 01/2011; 34(6):675-80. · 2.59 Impact Factor
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    ABSTRACT: A method for the synthesis of chitosan crosslinking 2,5-dimercapto-1,3,4-thiodiazole (CTS-DMTD) adsorbent and the determination of trace amount of palladium in geological samples was established. It was found that the adsorption capacity was significantly affected by the solution pH, with optimum pH value of 2.0, the saturated adsorption capacity was 16.2 mg · g−1 for Pd(II). The studies of desorption were carried out using various reagents and the optimum effect obtained by using thiourea. Under the optimized conditions, the detection limit (3σ) for Pd(II) was 0.015 mg · L−1 and the relative standard deviation was 4.7%.
    Analytical Letters 08/2010; 43(12):1857-1868. · 0.97 Impact Factor
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    ABSTRACT: The determination of triazine herbicides by ultrasonic-assisted ionic liquid microextraction coupled with high-performance liquid chromatography was described. 1-Hexyl-3-methylimidazolium hexafluorophosphate ([C6MIm][PF6]) was used as the extraction solvent and some extraction parameters, including volume of [C6MIm][PF6], extraction temperature and time, salt concentration and pH values of sample solution, were examined and optimized. The isolation of the target compounds from the matrix was found to be efficient when triazines in 10 mL of sample solution was extracted with 100 µL of [C6MIm][PF6] for 40 min at 50°C. The detection limits for the triazine range from 0.36 to 1.41 µg·L−1. The satisfactory recoveries (82.3% –120.3%) with relative standard deviations ≦10.1% were obtained for the four triazine herbicides from six kinds of practical water samples.
    Chinese Journal of Chemistry 06/2010; 28(5):785 - 790. · 0.92 Impact Factor
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    ABSTRACT: A new chemically modified chitosan hydrogel with 2,5-dimercapto-1,3,4-thiodiazole (CTS-DMTD) has been synthesized. The structure of CTS-DMTD was confirmed by elemental analysis and FTIR. It was found that adsorption capacities were significantly affected by the pH of solution, with optimum pH values of 3.0 for Au(III), 2.0 for Pd(II) and Pt(IV). The saturated adsorption capacities were 198.5 mg/g for Au(III), 16.2 and 13.8 mg/g for Pd(II) and Pt(IV), respectively. Langmuir and Freundlich isotherm adsorption models were applied to analyze the experimental data. The results showed that adsorption isotherms of Pd(II) and Pt(IV) could be well described by the Langmuir equation. The adsorption kinetic investigations indicated that the kinetic data correlated well with the pseudo-second-order model. The recovery experimental data showed that CTS-DMTD had a higher affinity toward Au(III), Pd(II), and Pt(IV) in the coexistence system containing Cu(II), Fe(III), Cd(II), Ni(II), Mg(II), and Zn(II). The studies of desorption were carried out using various reagents and the optimum effect was obtained using thiourea. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
    Journal of Applied Polymer Science 01/2009; 113(3):1604-1610. · 1.40 Impact Factor
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    ABSTRACT: The ultrasonic nebulization extraction (UNE) was developed and applied to extract anthraquinones (emodin, aloe-emodin and rhein) from Rheum palmatum L. Several parameters of UNE, including type of extraction solvent, concentration of extraction solvent, volume of extraction solvent, extraction time and ultrasonic power, were studied and the optimized parameters were selected. The operation conditions of micellar electrokinetic capillary chromatography (MEKC) were also studied. Under the selected conditions, contents of emodin, aloe-emodin and rhein obtained from different cultivated areas of R. palmatum L. were 1.08-2.04 mg/g, 0.65-1.16 mg/g and 0.70-2.90 mg/g, respectively. The relative standard deviations (RSDs) for emodin, aloe-emodin and rhein were 1.3-2.4%, 1.9-4.7% and 1.3-3.9%, respectively. Compared with maceration extraction (ME), reflux extraction (RE), stirring extraction (SE) and ultrasonic extraction (UE), the proposed method was more efficient, faster and easier to be operated and lower equipment costs and lower extraction temperature were required. The results indicated that UNE was a good alternative method for extracting anthraquinones from R. palmatum L. Compared with traditional extractions, the proposed extraction has a potential in on-line sampling, especially when the gas is used as the carrier of sample.
    Ultrasonics Sonochemistry 08/2008; 15(5):738-46. · 3.52 Impact Factor
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    ABSTRACT: A dynamic ultrasonic extraction (DUE) coupled with on-line detection by spectrophotometry is proposed for the determination of total flavonoids (calculated against scutellarin) in Scutellaria barbata D. Don. The extraction was performed in a common self-made extraction vessel put in an ultrasonic bath and a peristaltic pump was used to deliver the extraction solvent. Several experimental parameters of DUE, including flow rate and concentration of extraction solvent, ultrasonic power and sample amount, were optimized. In this work an on-line method was provided with the advantages of minimum sample amount (5 mg), on-line monitoring the extraction process and time saving (12.5 min). Compared with off-line method, the proposed method would be more convenient for obtaining continuous measurements and rapid optimization of the extraction process.
    Analytica chimica acta 04/2008; 610(2):217-23. · 4.31 Impact Factor
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    ABSTRACT: Crosslinked chitosan was modified with 4-amino-4′-nitroazobenzene and characterized by FT-IR and SEM. The adsorption of Au(III) and Pd(II) was optimum at pH3.0 for Au(III) and at pH2.0 for Pd(II), where maximum mass adsorption were 69.93mgg−1 and 58.58mgg−1, respectively. The adsorption isotherms obey the Langmuir equation in case of Au(III), and the Freundlich and Langmuir equations in case of Pd(II). The adsorption kinetics follows a pseudo-second-order model. This new adsorbent shows high affinity for Au(III) and Pd(II), while the adsorption is negligible for K , Na and Ca and no adsorption of several other metal ions occurs. The method was successfully applied to the determination and separation of Au(III) and Pd(II) in aqueous samples and ore.
    Microchimica Acta 168(1):99-105. · 3.43 Impact Factor
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    Microchimica Acta 170(1):189-189. · 3.43 Impact Factor
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    ABSTRACT: A simple, cheap, and nonpolluting method was developed for the cloud point extraction of gold (Au) and palladium (Pd). It is based on the complexation reaction of Au and Pd with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) and micelle mediated extraction of the complex using the non-ionic surfactant poly(ethylene glycol) mono-p-nonylphenyl ether (PONPE 7.5). Under the optimized experimental conditions, the enrichment factors are 16 and 17 for Au and Pd, respectively, for 15mL of preconcentrated solution. The limits of detection are 3.8μg L−1 and 1.8μg L−1 for Au and Pd, respectively. The relative standard deviations are 1.4% for Au and 0.6% for Pd (n = 11). The method was successfully applied to the determination of Au and Pd in certified reference materials and mine samples. FigureCPE of gold(III) and palladium(II) KeywordsGold–Palladium–Cloud point extraction–Flame atomic absorption spectrometry
    Microchimica Acta 172(1):95-102. · 3.43 Impact Factor