Patent ID: 9533266
Date: 2017-01-03
CPC Classifications: B01D

Claim:
1. A method for preparing a homogeneous tubular braid-reinforced (EMIR) PPTA hollow fiber membrane, which combines PPTA hollow tubular braids with PPTA surface separation layer, wherein the method comprises the following steps of: (1) preparing PPTA hollow tubular braids, wherein: the PPTA hollow tubular braids which are made from PPTA filament yarns are woven by a two-dimensional braided method, and they are served as a reinforced matrix for HMR PPTA hollow fiber membranes, wherein an outer diameter of the PPTA tubular braids is 1-2 mm; a filament yarn denier is 50-800 D; a woven pitch is 5-20 mm; (2) preparing the PPTA surface separation layer, wherein: dried PPTA resin, pore-forming agents and inorganic particles are mixed into an inorganic acid solvent, stirred for 1-3 hours at 70° C.-90° C. to form homogeneous and transparent casting solution, wherein components of casting solution and a mass fraction of surface separation layer are: wherein a logarithmic specific concentration viscosity of the PPTA resin is 4-10 dL/g; wherein the pore-forming agents are water-soluble macromolecule, which is polyethylene glycol (PEG) with an average molecular weight of 600-20000, or polyvinylpyrrolidone (PVP) with an average molecular weight of 10000-100000, or a mixture of the PEG and the PVP with a ratio of (4:1)-(10:1) by weight; wherein the inorganic particles are selected from a group consisting of silicon dioxide, titanium dioxide and graphene oxide; wherein the inorganic acid solution is concentrated sulfuric acid with a mass concentration at a range of 98-106 wt %; and (3) preparing reinforced PPTA hollow fiber membrane, wherein: the casting solution is evenly coated on the surfaces of the PPTA hollow tubular braids through spinneret, and then they are passed through an air bath of 1-10 cm under the winding tension, afterwards they are immersed in a coagulation bath of 0-50° C. for solidified formation, so as to obtain the HMR PPTA hollow fiber membranes, wherein a spinning temperature is kept at 60-80° C., a speed of winding tension is 1-30 m/h, a coagulation bath is a sulfuric acid solution with a mass fraction of no more than 30%.