A kind of nanocellulose-composite nanofiltration membrane (cnf-nf) and preparation method thereof

Abstract

The invention relates to the field of polymer separation membranes, in particular to a nanocellulose-composite nanofiltration membrane (CNF-NF), comprising a bottom membrane, a main support layer and a separation skin layer, which are arranged in sequence and have decreasing pore diameters in sequence; There is an aqueous binder between the base film and the main support layer; the base film, the main support layer and the separation skin layer are respectively a polyacrylonitrile film, a cellulose nanocrystalline layer and a polyamide layer. The invention adopts a multi-layer composite structure, wherein the cellulose nanocrystals are one-dimensional nanomaterials with good hydrophilicity, mechanical strength and swelling resistance; the introduction of the cellulose nanocrystal intermediate layer can provide physical support for the cortex; the The preparation process of the nanofiltration membrane is simple to operate, the reaction conditions are mild, and it has a good industrial production basis and broad application prospects.

Description

technical field [0001] The invention relates to the field of polymer separation membranes, in particular to a nanocellulose-composite nanofiltration membrane (CNF-NF) and a preparation method thereof. Background technique [0002] Nanofiltration membrane is a new type of separation membrane with a pore size between reverse osmosis membrane and ultrafiltration membrane. still has a high desalination rate. Compared with ultrafiltration and reverse osmosis, nanofiltration has selectivity for the retention of inorganic salts. , so nanofiltration membranes can be used to separate salt ions of different valence states. In addition, the relative molecular weight of nanofiltration membrane is between 200 and 1000 Da, so it has a good interception effect on small molecular organic compounds with molecular weight above 200 Da. [0003] At present, nanofiltration membrane technology has been widely used in water softening and brackish water desalination, drinking water purification,...

AI Technical Summary

Problems solved by technology

Although the nanofiltration membrane prepared by traditional organic membrane materials has excellent mechanical properties and selectivity, there are also disadvantages: most organic matter is obtained from fossil resources through a series of reactions, and the increasing shortage of resources will inevitably restrict the development of membranes; There will be certain environmental problems in the process of membrane production and the treatment stage of the life cycle of polymers, such as the difficulty of degrading waste membrane materials, etc.