| Photocatalyst TiO2 has become a research hot spot in environmental and material field, because of its high photocatalytic activity, chemical stability, low cost, and nontoxicity in water treatment, air purification, etc. Using the photocatalytic of TiO2 nanoparticles with the polymer as carrier, the high photochemical catalysis and the high selectivity would be suggested, the catalysis efficiency is enhanced very much.TiO2/activated carbon composite nano-membrane were prepared by electrospinning technique, pre-oxidation, carbonization, activation.The solution prepared for spinning concludes PAN, DMF and the sol-gel of Ti(OH)4 for TiO2 particle, the homogeneous nanometer fiber mats whose diameter is about 700nm. The TGA,FTIR, XRD, and the contact angle indicated the physicochemical properties of the nanofiber, it also explained the difference during the period of the composite nano-membrane between pre-oxidation and carbonization. The equilibrium and dynamic adsorption experiments of simulated water of Methylene Blue are carried out to indicate the performance and the regeneration of TiO2/activated carbon composite nano-membrane. We studied the conditions which affected the removal efficiency of MB and the adsorption kinetics. The dynamic adsorption column was prepared to indicate the adsorption efficiency and the ability and regeneration of TiO2/activated carbon composite nano-membrane in different irradiations of solar energy and UV light.Micro-structrue and properties of the composite nano-membrane were characterized by Thereto-Gravimetr Analysis (TGA),Fourier transform infrared spectroscopy (FTIR),X-ray diffraction (XRD) and the water contact angle (CA) method,and so on. Structure of composite nano-membrane have been formed ladder structure in the period of stabilization process at 280℃, oxidation degree of fibers is suitable. Internal microstructure of stabilization composite nano-membrane has changed hexatomic ring-like and graphite-like structure in the process of carbonization at 500℃.It is show that composite nano-membrane change into TiO2/activated carbon composite nano-membrane completely.When using energy spectrum analysis, we can find that the amount of Ti in every point of the nanofiber belt is similar and uniform.The loaded amount of TiO2 is around 6%, the water contact angle is 135.1°, the composite nano-membrane shew a strong hydrophobic characteristics, but after pre-oxidation, activation and adsorption saturation, contact angle and hydrophobic characteristics were changed. The adsorption capacity of TiO2/activated carbon composite nano-membrane is about 23mg/g, the composite nano-membrane has the largest removal efficiency when pH=6-9, initial concentration of MB is 5mg/L, and the amount of TiO2/activated carbon composite nano-membrane is 1g. In addition, the kinetic data were fitted by Langmuir isotherm model, Freundlich isotherm model, pseudo-first-order equation, pseudo-second-order equation, and intra-particle diffusion model were presented. The results showed that the adsorption data fitted Freundlich isotherm model, and the maximum adsorption capacity of methylene blue would increase with the temperature increasing. Furthermore, the pseudo-second-order equation and intra-particle diffusion model generated the best agreement with the experimental data for the adsorption systems. The intra-particle diffusion was the main rate controlling step. When using both polar energy and UV light to regeneration, the zeta potential of TiO2/activated carbon composite nano-membrane stays stabale, the composite nano-membrane retained high photocatalytic activity even after 8 uses.In conclusion, this new material has its unique advantage in water purification, because of its feasibility in the separation and in photocatlyst recycling, and increases the applicability in practical application. TiO2/activated carbon composite nano-membrane guarantee its higher photocatalytic properties because of synergistic effect of TiiO and ACF. In addition, TiO2/activated carbon composite nano-membrane can save energy because it can take advantage of natural light to photocatalyze and regenerate, and provide a theoretical basis for the study of catalysis. TiO2/activated carbon composite nano-membrane has a good prospect in water treatment and waste water purification.----(Environmental Science) Supervised by----...
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