Multi-functional Water Purifier For Disinfection And Removal Of Dyes And Metal Ions And Self-assembly Of Poly(Vinylidene Fluoride)Block Copolymers In Solution

The thesis includes two parts:one is multi-ffunctional water purifier for disinfection and removal of dyes and metal ions,the other is self-assembly of poly(vinylidene fluoride)block copolymers in solution.1.In this study,we describe a sophisticated preparation of an inorganic/organic composite sample for the simultaneous removal of anionic dyes and metal ions,as well as disinfection.The sample has a stable structure formed by the covalent connection between a magnetic silica(MS)core and a polyethylenimine derived quaternary ammonium compound(QAC)corona.We characterized the sample in details by SEM,TEM,EDX,FT-IR,XRD,TGA and VSM.We then demonstrated the excellent adsorption abilities of the QAC-MS product towards two pollutants,i.e.Cu2+ and acid fuchsin(AF)as representatives of metal ions and dyes,as well as its disinfection ability towards Escherichia coli(E.colt).The adsorption experiment results showed that the QAC-MS exhibited maximum adsorption capacities of 653 mg/g for AF and 73.0 mg/g for Cu2+.In regards to the data fitting by the intra-particle diffusion model,we know that the whole adsorption process might be jointly controlled by external mass diffusion and intra-particle diffusion.The disinfection experiment results demonstrated a high bactericidal performance towards E.coli.Moreover,the QAC-MS exhibited an excellent stability and reusability for both adsorption and disinfection experiments over five cycles due to its ultra-stable structure.2.We report the first preliminary and extensive study on the solution self-assembly behaviors of poly(vinylidene fluoride)-b-polystyrene(PVDF-PS)block copolymers.The two PVDF-PS polymers we examined have the same length of PVDF block with number averaged repeating unit of 180,but distinctly different lengths of PS block with number averaged repeating unit of 125 and 1202.The self-assembly experiments were carried out in a series of mixture solutions containing a good solvent N,N-dimethylformamide and a selective solvent with different ratios.Our results showed that the self-assembly process was greatly affected by the two factors we examined,i.e.the length of the PS block and the solvent composition.We hope that our study could stimulate more research on the self-assembly of PVDF-containing polymer in solution.