Preparation And Characterization Of Ionic Liquid Modified PVDF/TiO₂ Nano Membrane

Membrane techhology as a new type of water treatment technology that is low energy consumption and non-pollution has become a hot spot in the field of scientific research, and the application has become more and more widely. For organic materials, the defect such as mechanical strength and chemical stability limits the scope of application of organic membrane. Organic-inorganic membrane although can improve the performance, but there are still some problems difficult to overcome such as the reunion of inorganic paticles and insufficient ideal effect of modification, which limit the actual production of these membranes. In order to overcome the limitation of the material in membrane preparation and improve its performance in water treatment, reseatchers have continued carring out the modification of inorganic paticles and then hybrid to the membrane. As a green solvent, ionic liquids have good chemical stability and the structure can be designed, which have great potentiality in improving the physicochemical properties of inorganic nano-paticles and further improving the performance of organic-inorganic hybrid membranes. Based on this, we carried out the research of ionic liquid modified PVDF/TiO₂ nano-membrane.The traditional heating reflux method was used to preparate the ionic liquid, and then the ionic liquid was introduced in the preparagion of the nano-TiO₂ paticles. It was found that the ionic liquid is a high asymmetric satructure and the carboxyl of ionic liquid happened deprotonation and polycondensation in the modification process of nano-TiO₂, then bonded with it and formed TiO₂-IL particles.Thermally induced phase separation (TIPs) was used to preparate PVDF/TiO₂ and PVDF/TiO₂-IL membranes. It was found in the characterization of these membranes that the existence of ionic liquid enhanced the force between nanopaticles and the diluent (DMP), hindered the reunion of nano-particles. The addition of TiO₂ dose not changed the crystal of PVDF and was physical blend, but the addition of TiO₂-IL induced the formation ofβ-PVDF.The water treatment performance of PVDF/TiO₂-IL membranes was inspected, the results showed that the membrance have very good remvol efficiency of turbidity and Fe, but poor remvol efficiency of organic matter and Mn. The addition of nano TiO₂-IL particles made the water flux and water treatment performace of the membrane with an improvent in some extend.