| Adsorption thermodynamics and kinetics of metal thiosulfate complex on activated carbon were studied.The influence of mole ratio,pH value and temperature on the adsorption process were examined,and the optimum adsorption conditions were selected.Under the optimal adsorption condition,the saturated adsorption capacity of activated carbon for copper,silver,gold thiosulfate complex is 85.6 mg/g,18 mg/g,and 0.762 mg/g respectively.It is concluded that the relationship of three kinds of metal complex adsorption capacity is copper>silver>gold.The adsorption kinetics was investigated.The results showed that the adsorption process of copper,silver and gold thiosulfate complex conform to the quasi-secondary adsorption dynamics.Furthermore,activated carbon adsorption of copper and silver thiosulfate complex process is in line with the Freundlich model,and activated carbon adsorption gold thiosulfate complex process is in line with the Langmuir model.In order to exqplore the mechanism of adsorption further more,the activated carbon after adsorption were characterized by scanning electron microscope(SEM),Fourier transform infrared spectrometer(FT-IR),X-ray photoelectron spectrometer(XPS)respectively.As indictaed by SEM,the surface of activated carbon between before and after adsorption was significantly changed.Before the adsorption,the activate carbon surface is rich in microporous,with clear texture,wheras,after adsorption,some carbon skeleton structure has begun to be corrosion,and the pore structure is damaged.The functional groups on the surface of activated carbon was deterimined by FT-IR.The surface both before and after adsorbtion are with hydroxyl and carbonyl.The bond between carbon and oxygen in copper system is almost disappear after adsorption.XPS was used to study the chemical status of the elements on active carbon surface after adsorption.Combined with infrared spectrum analysis,the mechanism of activated carbon adsorption was discussed. |
PDF Full Text Request