| Based on the overview of the characteristic of nano-sized magnesium hydroxide and its development of synthetic method and the theories of adsorption, the dissertation included following contents:1. Two kinds of nano-sized magnesium hydroxide powder were prepared by magnesium chloride, sodium chloride and sodium hydroxide using the solid phase method without solvent. A comparison of puity, crystal form and other characteristic for two samples was characterized by XRD and SEM.2. The adsorption property of Co(II) in aqueous solution by nano-sized magnesium hydroxide powder was studied with spectrophotometry. The effect of pH, adsorption time, temperature, adsorbent dosage and initial Co(II) concentration were investigated. And the optimum conditions were obtained under the conditions at pH=6.3, temperature of 298K, adsorption time of 15min and adsorbent dosage of 2g/L. The adsorption process can be simulated by Langmuir isotherm. Thermodynamic parameters such as free energy change, enthalpy change and entropy change were calculated. The adsorption seems to be a spontaneous and endothermic process and the process is a physical adsorption. Moreover, this adsorption fits pseudo-second-order model in kinetics.3. The adsorption property of Ni(II) in aqueous solution by nano-sized magnesium hydroxide powder was studied with spectrophotometry. And the experimental results showed that the optimum conditions were pH=6, temperature of 298K and the adsorption time of 30min by experiments. The adsorption process fits Langmuir isotherm very well. The thermodynamic parameters such as free energy change, enthalpy change and entropy change were calculated. The results show that the adsorotion process is a physical, spontaneous and endothermic process. And the kinetics experiments show the adsorption is a pseudo-second order process.
|
PDF Full Text Request