Composite nanofiltration membrane with heavy metal interception capability

Abstract

The invention discloses a composite nanofiltration membrane with heavy metal interception capability. The composite nanofiltration membrane is obtained by depositing amino cucurbituril intercalated graphene on a porous base membrane, wherein the base membrane is a nanofiber membrane prepared by taking graphene oxide, tyrosine, carboxymethyl hydroxypropyl guar gum and polyacrylamide as raw materials and adopting an electrostatic spinning method. The composite nanofiltration membrane has good stability and high water flux, has good interception capability on divalent / high-valent anions, heavy metal ions and anionic dyes, and is expected to be applied to treatment of heavy metal and organic dye polluted wastewater.

Description

technical field [0001] The invention belongs to the field of preparation of nanofiltration membranes, in particular to a composite nanofiltration membrane with heavy metal retention capacity. Background technique [0002] In recent years, with the development of the economy and the advancement of global industrialization, industrial wastewater contains a variety of heavy metals and organic dyes and other refractory pollutants that pose a threat to human health; the treatment of industrial wastewater has become one of the environmental problems that need to be solved urgently. 1. With the development of membrane separation technology, the use of membrane separation technology to treat wastewater pollution is popular because of its low cost and environmental friendliness; [0003] Nanofiltration membranes are widely used in wastewater treatment because of their low energy consumption, high flux, and good retention capacity for ions and organics, but the existing single-layer n...

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Problems solved by technology

[0003] Nanofiltration membranes are widely used in wastewater treatment because of their low energy consumption, high flux, and good retention capacity for ions and organics, but the existing single-layer nanofiltration membranes cannot meet the requirements of good retention performance and high flux ; In order to solve this problem, a composite membrane is usually obtained by a composite method. The composite method refers to a separation layer with a micro-nano pore size on the ultrafiltration or microfiltration base membrane, and it can use different materials as the base membrane and the separation layer. , but there is often a large difference in swelling between the basement membrane and the separation layer, and the weak binding force between the two causes the separation of the separation layer and the basement membrane in the later use and cleaning process and reduces the membrane. Usability; at the same time, the separation layer will significantly affect the interception performance and flux of the composite membrane, so the preparation of a separation layer with good selective screening ability plays an important role; the traditional composite method includes interfacial polymerization or surface coating method, due to the structure The dense functional layer of the nanofiltration membrane is thicker, which will reduce the flux of the nanofiltration membrane. In order to obtain a higher flux, the operating pressure must be increased, which will increase the operating cost; in addition, the interfacial polymerization method needs to consume a large amount of organic solvents. Solvent residues will cause environmental pollution; at the same time, the traditional nanofiltration membrane liquid has a low interception rate for heavy metal ions or even cannot achieve interception; therefore, it is urgent to research and develop a composite nanofiltration membrane with heavy metal interception capacity

[0004] The electrospinning method is to make the charged polymer solution or melt flow and deform in the electrostatic field. When the electric field force is large enough, the polymer droplets can overcome the surface tension to form a jet stream, and then evaporate through the solvent or the melt Cooling and solidification to obtain fibrous substances, the preparation of nanofiber membranes by electrospinning has become a main method of nanofiber membranes at present. Nanofiber membranes have good adsorption and filtration capabilities due to their porous structure and large specific surface area, but Pure nanofibrous membrane as a filter membrane has the problem of low mechanical strength and poor separation performance; therefore, using an electrospun membrane as a base membrane to compound a functional layer on its surface can significantly improve the mechanical strength and separation performance of the composite membrane

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