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Preparation of crosslinked chitosan azo compounds and metals separation and determination of precious metals commonly used in the separation and detection methods, the preparation of chitosan derivatives and its applications in precious metals separation Overview; using chitosan as maternal synthesis of the two azo crosslinked chitosan derivative, 4'-nitro-4 - the aminoazobenzene crosslinked chitosan (CS-PANAB) and 3'-nitro-4 - aminoazobenzene benzene crosslinked chitosan (CS-MANAB), noble metal ions were measured by atomic absorption spectrophotometry. By FT-IR, SEM adsorbent characterization, effects of adsorbent expensive so the static adsorption behavior of metal ions in the hydrochloric acid solution, the pH of the solution, adsorption time, initial concentration of metal ions, desorption, etc. impact on the kinetics and thermodynamics of noble metal ions adsorption behavior are discussed, and finally using standard ore samples investigated the feasibility of this method, as follows: (1) CS-PANAB of Au (Ⅲ). Pd (Ⅱ) The best adsorption acidity pH 3.0,2.0; optimum acidity, was to Dao CS-PANAB Au (III), Pd (II) the maximum adsorption capacity were 69.9300mg / g, 58.5800 mg / g. The CS-MANAB Au (III), Pd (II), Pt (Ⅳ) white spoon optimum adsorption acidity, the pH 5.0,4.0-6.0,3.0; the CS-MANAB of Au (Ⅲ). Pd (Ⅱ). Pt (IV) The maximum adsorption capacity were 35.7142 mg / g, 29.3255 mg / g, 43.1034 mg / g. (2) Langmuir and Freundlich the thermodynamics adsorption model fitting analysis of the experimental data, C S-PANAB follow the Langmuir equation for the adsorption of Au (Ⅲ), Pd (II) adsorption followed Langmuir and Freundlich isotherm equation ; CS-MANAB Au (III) Pd (II), Pt (IV) adsorption followed the Langmuir thermodynamic model. (3) The proposed second-order kinetic model and intraparticle diffusion model were used to dig in the number of dynamics discussed. CS-PANAB adsorption of Au (III), Pd (II) the pseudo-second kinetic equation fitting correlation coefficient, the adsorption process is affected by the concentration changes affect the larger: CS-MANAB Pd (II) Pt ( Ⅳ) adsorption behavior by pseudo-second-order kinetics model fitting results, the adsorption of Au (III) with a particle diffusion model fitting straight line through the origin. (4) in the two-component experiments, the synthesis of the two adsorbents of Au (Ⅲ), Pd (Ⅱ), Pt (Ⅳ) with a good choice of performance of other base metal ions adsorbed amount with little or no adsorption. (5) with different concentrations of thiourea, thiourea - hydrochloric acid solution desorption behavior of noble metal ions. It was found that: 1.00 mol / L thiourea and 0.50 mol / L thiourea is desorbed from the CS-PANAB Au (III), Pd (II) the appropriate desorbent, the desorption rate of 82.97%, 87.73% ; 0.20 mol / L thiourea -0.50 mol / L hydrochloric acid solution from the CS-MANAB Au (III), Pd (II) and Pt (IV) desorption most effective desorption rates were 92.21%, 90.40% and 93.38%. (6) ore sample analysis CS-PANAB, determination of Au (Ⅲ), Pd (Ⅱ) The relative standard deviation (n = 6) were 2.76%, 4.33%; For CS-MANAB, the relative standard deviation (n = 6) were 5.10% (Pd), 3.76% (Pt), 3.64% (Au, GBW (E) 070015), 4.63% (Au, MG-1); Au (Ⅲ), Pd (Ⅱ), Pt (IV) detection limit of 0.010 mg / L, 0.015 mg / L, 0.024 mg / L. The experimental results show that the synthesis two adsorbents the CS-PANAB and the the CS-MANAB of Au (Ⅲ), Pd (Ⅱ) and Pt (Ⅳ) with high selective adsorption performance, strong anti-jamming capability, the recycling rate advantages can be successfully used for ore samples and the separation and detection of precious metal ions in solution, the separation and extraction of the precious metal ions has a certain theoretical and practical significance.
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