Nanocellulose-compound nanofiltration membrane (CNF-NF) and production method thereof

Abstract

The invention relates to the field of polymeric separation membrane, in particular to nanocellulose-compound nanofiltration membrane (CNF-NF). The nanocellulose-compound nanofiltration membrane (CNF-NF) comprises base membrane, a main supporting layer and a separation skin layer which are sequentially arranged, wherein pore diameters of the base membrane, the main supporting layer and the separation skin layer decrease progressively; a water-based binder located between the base membrane and the main supporting layer is arranged on the main supporting layer; and the base membrane, the main supporting layer and the separation skin layer are polyacrylonitrile membrane, a cellulose nanocrystalline layer and a polyamide layer respectively. The nanocellulose-compound nanofiltration membrane (CNF-NF) is of a multi-layer compound structure, wherein cellulose nanocrystalline is a one-dimensional nanometer material, and has good hydrophilicity, mechanical strength and resistance to swelling; byintroducing the cellulose nanocrystalline middle layer, physical support can be provided for the skin layer; and a production process of the nanofiltration membrane is simple to operate and mild in reaction condition, and the nanofiltration membrane has a good industrial production basis and wide 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] The nanofiltration membrane is a new type of separation membrane with a pore size between the reverse osmosis membrane and the ultrafiltration membrane. It still has a high desalination rate. Compared with ultrafiltration and reverse osmosis, nanofiltration is selective for the interception of inorganic salts. Its rejection rate for monovalent salts is relatively low, and its rejection rate for divalent or multivalent salts is relatively high, usually higher than 90%. , so nanofiltration membranes can be used to separate salt ions of different valence states. In addition, the relative molecular weight cut-off of the nanofiltration membrane is between 200 and 1000 Da, so it has a good cut-off effect on small molecular organic substances with a mol...

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.