Charged TiO2/polyelectrolyte composite nanofiltration membrane as well as preparation method and application thereof

Abstract

The invention discloses a charged TiO2 / polyelectrolyte composite nanofiltration membrane as well as a preparation method and an application thereof, and belongs to the technical field of membrane separation. The preparation method comprises the following steps: firstly, the surface of a base membrane is charged, so that the base membrane and polyelectrolytes can conveniently generate an electrostatic effect; secondly, the composite nanofiltration membrane is prepared with a method for alternatively depositing anionic and cationic polyelectrolytes and performing electrostatic layer-by-layer self-assembly. Inorganic nanoparticles adopted in the preparation method are modified negatively charged / positively charged TiO2 nanoparticles; as TiO2 has the advantages of good photocatalytic performance, good hydrophilicity and the like, TiO2 is combined with layer-by-layer self-assembly to prepare the TiO2 / polyelectrolyte composite nanofiltration membrane; the preparation method is simple and convenient to operate and is an environment-friendly preparation method; moreover, the prepared TiO2-containing composite nanofiltration membrane has very good hydrophilicity and charge performance, has good pollution resistance, is uniform in structure and can be used for removing divalent metal ions such as Ni<2+> and the like in wastewater as well as dye molecules such as dimethylphenol orange, eriochrome black T and the like at the same time, thereby having a good application effect.

Description

technical field [0001] The invention belongs to the technical field of membrane separation and relates to a charged TiO 2 / Polyelectrolyte composite nanofiltration membrane, preparation method and application. Background technique [0002] Nanofiltration (NF) membrane is a pressure-driven membrane between ultrafiltration (UF) membrane and reverse osmosis (RO) membrane, which was developed in the early 1980s. Due to its special charging performance and membrane pore size distribution, nanofiltration membranes play an irreplaceable role in the fields of food processing, biopharmaceuticals, petrochemicals, and wastewater treatment. At present, the preparation of nanofiltration membranes is mostly to cover a very thin selective separation layer on the surface of the base membrane with better strength and larger flux. The preparation methods mainly include coating method and phase inversion method (such as patent CN 102091539A ), interfacial polymerization (such as patent CN 10...

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Problems solved by technology

At present, the preparation of nanofiltration membranes is mostly to cover a very thin selective separation layer on the surface of the base membrane with better strength and larger flux. The preparation methods mainly include coating method and phase inversion method (such as patent CN 102091539A ), interfacial polymerization (such as patent CN 101254419 A, CN 101559334 A), etc., surface grafting method (such as patent CN 102000511 A, CN 102068912 A), etc., but these methods have higher requirements on the base film and many side reactions. It is difficult to obtain nanofiltration membranes with ultra-thin layers; layer-by-layer self-assembly technology is an important ultra-thin film preparation technology that has developed rapidly in recent years. Separation layer, and finally a composite nanofiltration membrane is prepared

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