A kind of hollow fiber polymer membrane, preparation method and its application in brine refining

Abstract

The invention provides a preparation method of a hollow fiber polymer membrane, particularly relates to a membrane filter using the membrane in the process field of brine refining, and belongs to thefield of polymer separation membrane preparation. ECTFE (ethylene-chlorotrifluoroethylene copolymer) is used as a membrane material for preparing the hollow fiber membrane; the hollow fiber membrane is applied to a brine refining process. The average pore diameter of the prepared hollow fiber membrane is 150 to 220nm; the tensile strength is 2.5 to 4.7MPa; the pure water flux at 25 DEG C is 320 to710L / (m2.h.bar). The ECTFE, a diluent and an inorganic additive are proportionally mixed; heating dissolving is performed; a prepared casting membrane solution is spun into a hollow fiber shape by aspinning machine; then, quenching is performed; the prepared membrane silk is firstly subjected to acid pickling; then, the diluent is extracted by a proper solvent; drying is performed to obtain an ECTFE hollow fiber membrane. The hydrophilicity of the membrane prepared by the method is improved; the tensile strength is high; the pure water flux of the membrane is great; the pore diameter is concentrated; the pollution resistant performance is good; a good application effect is realized in the brine refining process.

Description

technical field [0001] The invention relates to a method for preparing a hollow fiber membrane, in particular to a membrane filter using the membrane used in the field of brine refining technology, belonging to the field of polymer separation membrane preparation. Background technique [0002] The brine refining process is one of the main processes in the caustic soda production process. The technical and economic indicators and operating life of the diaphragm cell or ion membrane cell used in the brine electrolysis in the chlor-alkali industry are closely related to the quality of the brine entering the tank. High-quality brine is directly related to the power consumption of production and the life of the ionic membrane, so improving the quality of brine has always been the goal of the chlor-alkali industry. In the chlor-alkali production process, no matter which raw material is used in lake salt, sea salt or brine, they all contain inorganic impurities such as calcium and ...

AI Technical Summary

Problems solved by technology

[0006] However, the Gore membrane and the Kay membrane process have two common shortcomings: 1) The dead-end filtration method is adopted, which limits its further development

2) The pore size of the PTFE membrane used in the membrane filter is not easy to control, and the pore size distribution is wide, which aggravates the process of membrane fouling, resulting in a short service life of the PTFE membrane, which greatly limits its development in the market

In addition, the membrane filter components usually used in the process of treating refined brine by traditional membrane methods are tubular membranes, and the packing density of tubular membranes is small, and the membrane area is small, resulting in low water flux.

Due to the high packing density, the hollow fiber membrane is much larger than the membrane surface area of ​​the tubular membrane, and the water flux is large, but the strength of the traditional hollow fiber membrane is not high, and it is easy to break. These reasons are also the reasons why it has not been applied in the field of brine purification.

At present, there is no literature report on the application of ECTFE membrane in the brine refining process, but it is very meaningful to develop a ECTFE hollow fiber membrane and apply it in the brine refining process

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