Investigation On The Adsorption Removal Of Silver And Gold Nanoparticles From Aqueous Water

With the development of nanotechnology, the impact of the increasing use of nanomaterials on the ecological environment and the biological health has gradually been concerned. The anomaterial in the environment can enter into the human body through the food chain and produce toxic effects, leading to a serious threat to human health. Hence, it is urgent to study the methods for the removal of nanoparticles. In this thesis, the adsorption properties of carbon materials such as activated carbon and PEI-Fe3O4-GO for silver nanoparticles and gold nanoparticles in water were studied, and the influence of various factors on the adsorption was investigated. The major contents are summarized as follows:1. In this experiment, we use activated carbon to remove the silver nanoparticles. The adsorption behavior of silver nanoparticles onto activated carbon was studied. The effects of solution pH, salt concentration, humic acid, temperature and different ligands indicated were investigated. The result indicated that the good adsorption of silver nanoparticles occurred at pH 6. The increase in temperature promoted the adsorption of silver nanoparticles onto active carbon. The adsorption capacity decreased in the presence of humic acid. The ligands have significant effect on the adsorption of silver nanoparticles onto active carbon. The adsorption of silver nanoparticles with large particle size by active carbon is poorer, whereas, it is better for the silver nanoparticles with smaller particle size. Adsorption kinetics and isotherms have also been studied in experiment.Kinetics of nanoparticles adsorption was found to follow the pseudo-second-order rate equation and the adsorption process was fit well with the Langmuir adsorption isotherm, the maximum adsorption capacity can reach 68.4 mg/g, that activated carbon as an adsorbent can effectively remove silver nanoparticles in water.2. The PEI-Fe3O4-GO was prepared by ligand exchange method and characterized by TEM, FT-IR, Raman, VSM, zeta potential determination. The adsorption removal of Cir-Ag NPs by PEI-Fe3O4GO was investigated under different pH, humic acid, salt and ligands. The result indicated that the good adsorption of silver nanoparticles occurred at pH 6. The adsorption capacity decreased in the presence of salt and humic acid. Kinetics of nanoparticles adsorption was found to follow the pseudo-second-order rate equation and the adsorption process was fit well with the Langmuir adsorption isotherm, the maximum adsorption capacity can reach 132.28 mg/g. And PEI-Fe3O4-GO can be rapid separated with the help of external magnet from aqueous solution.Therefore, PEI-Fe3O4-GO can be used as an effective adsorbent for the removal of silver nanoparticles in water.3. The PEI-Fe3O4-GO was used for adsorption of Cir-Au NPs from aqueous. Various factors including solution pH, humic acid, concentration of salt, different ligands affecting the adsorption were explored. The result indicated that the good adsorption of gold nanoparticles occurred at pH 6. The adsorption capacity decreased in the presence of salt and humic acid.Kinetics of nanoparticles adsorption was found to follow the pseudo-second-order rate equation and the adsorption process was fit well with the Langmuir adsorption isotherm, the maximum adsorption capacity can reach 236.96 mg/g. And PEI-Fe3O4-GO can be rapid separated with the help of external magnet from aqueous solution. Therefore, PEI-Fe3O4-GO can be used as an effective adsorbent for the removal of gold nanoparticles in water.