Preparation And Characterization Of Functionalized Nano-adsorbent And Investigation Of Its Adsorption Property

Owing to its excellent physical and chemical properties, nanomaterial attracts wide interests from researchers of different areas. Compared to the corresponding material at macroscopic scale, nanomaterial exhibits many excellent characters in the field of magnetics, optics, thermology, and electricity, due to its large ratio of surface area to volume, large fraction of surface atoms to that in its bulk, and small size. Therefore, nanomaterial is extensively used in biological probe, imaging, drug delivery, magnetic hyperthermia, catalysis and adsorption. In the present thesis, chapter1is the review of preparation and characterization of functionalized nano-adsorbent and applications of nanomaterial in adsorption of contaminated substances in aqueous solution; based on chapter1, chapter2-4are some original research works during the study of master’s degree.Chapter1:The concept, properties, synthetic methods and characterization techniques of nanomaterial, knowledge of adsorption and applications of nanomaterial in adsorption of contaminated substances in aqueous solution were introduced and reviewed.Chapter2:Based on the optimization of the preparation and adsorption conditions of the adsorbent, hexadecyl functionalized magnetic silica nanoparticles (C16/SiO2-Fe3O4NPs) was prepared by a facile method and characterized by X-ray diffractometer, transmission electron microscope, Fourier transform infrared spectrometer and vibration sample magnetometer. The adsorbent prepared maintaining volume ratio of tetraethylorthosilicate to hexadecyltrimethoxysilane at1:0.5and their total volume at1100μL exhibited high adsorption capacity. The optimum pH value for the adsorption experiments was11.00. The adsorption behavior of Rhodamine6G onto C16/SiO2-Fe3O4NPs obeyed pseudo-second-order kinetic model and Langmuir isotherm model. Thermodynamic data indicated that the adsorption process was spontaneous and exothermic. The adsorption capacity of the adsorbent could reach to35.6mg·g-1, owing to the hydrophobic attraction and the enhanced electrostatic attraction. The saturation magnetization of the magnetic adsorbent was35emu·g-1, which ensured the convenient magnetic separation after adsorption.Chapter3:A new multifunctional mesoporous nano-adsorbent, amino and phenyl functionalized CTAB doped mesoporous silica nanoparticles (APCMSN), was synthesized by a one-step method without template extraction. The adsorbent was characterized by X-ray diffractometer, transmission electron microscope and Fourier transform infrared spectrometer. The adsorption of APCMSN for m-nitrophenol and bisphenol A was investigated with respect to different conditions, including initial solution pH, agitating time and KCl concentration. Experimental results demonstrated that;m-nitrophenol and bisphenol A could be effectively adsorbed by APCMSN in aqueous solution without adjusting solution pH. The adsorption of APCMSN for m-nitrophenol and bisphenol A obeyed pseudo-second-order kinetic model and showed agreement with both Langmuir and Freundlich isotherm model. Adsorption capacity of APCMSN for m-nitrophenol and bisphenol A could reach63.7mg·g-1and128.9mg·g-1, respectively. Thermodynamic parameters indicated the adsorption was feasible, spontaneous and endothermic.Chapter4:Fe3O4/graphene nanocomposite was prepared by solvothermal method and characterized by transmission electron microscope, Fourier transform infrared spectrometer and vibration sample magnetometer. Effects of solution pH, agitating time and adsorbate concentration on adsorption capacity of Fe3O4/graphene nanocomposite for aniline and p-chloroaniline was investigated. Experimental results demonstrated that aniline and p-chloroaniline could effectively be removed from aqueous solution within60min by Fe3O4/graphene nanocomposite without adjusting solution pH. The adsorption of aniline and p-chloroaniline onto Fe3O4/graphene nanocomposite obeyed pseudo-second-order kinetic model and Freundlich isotherm model. The saturation magnetization of the Fe3O4/graphene nanocomposite was about120emu·g-1, which ensured the convenient magnetic separation after adsorption.