Preparation of Hollow Fiber Membranes by Nonsolvent Induced Phase Separation along with Hydrogen Gas Formation Using a Single Orifice Spinneret

Abstract

air gap distance, [7][8][9] flow rates of polymer solution, [10][11][12] and bore fluid, [13][14][15] phase behavior of polymer/solvent/nonsolvent ternary system, and rheology of polymer solution. [16,17] Composition, temperature, and pH of coagulation bath are also impor tant parameters that influence the mor phologies and properties of HFMs. [18][19][20] HFMs were fabricated by phase inver sion process of polymer solutions in late 1950s, which were mainly intended for a wide variety of purification and separation processes. [21] So far, many different types of HFMs have been manufactured by this method. [22,23] HFMs are mainly fabricated by nonsolvent induced phase separa tion (NIPS) and thermally induced phase separation techniques, which are effective strategies to produce HFMs with desirable structures and properties, in both labora tory and industrial scales. In a typical solution spinning and phase inversion process, an HFM is fabricated by extruding a concentrated polymeric solution through an annular gap of a concentric orifice spin neret into the external coagulation bath. [21] NIPS process is based on the exchange of solvent present inside the polymer solution with the nonsolvent in the coagulation bath to induce a phase separation of polymer solution from a liquid disper sion to a solid state. [24,25] In the wet spinning method, the dia meter and wall thickness of the HFMs mainly depends upon the inner/outer diameter of the spinneret and the properties of poly mer solution, since the stretching of the fibers is quite limited in this process. Efforts were made to overcome the for mation of irregular surface at high speed spinning rate. [26] In fact, the fabrication process of HFMs faces significant challenges. On the one hand, there is a need to redesign and fabricate fine spinnerets and replace them to regulate hollow fiber membranes. On the other hand, high quality pumps are required to obtain continuous and stable flow in order to ensure the stability of the hollow fiber membranes. These dif ferent factors limit the applicability of traditional techniques to produce HFMs.Lately, a new strategy was developed to solve these problems. HFMs were fabricated by a modified NIPS process, by using a spinneret with ingle orifice. Yao et al. [27] added organic oil to the polymer dope solution as a boreforming agent. The oil was pushed by the external coagulant (water) to the center of the fiber, and thus the HFMs could be obtained by washing away Hollow Fiber MembranesTraditional nonsolvent induced phase separation (NIPS) process for fabrication of hollow fiber membranes (HFMs) faces challenges, like design and manufacture of spinneret with two concentric orifices to provide parallel and continuous feed of polymer solution and bore fluid at specific rates. These factors limit the use of traditional technique to produce HFMs. Here, a new direct spinning method for fabricating HFMs by feeding a polymer solution, containing a gas producing agent using single orifice spinneret is reported. Polysulfone-dimethylacet...

Catalytic and Photocatalytic Electrospun Nanofibers for Hydrogen Generation from Ammonia Borane Complex: A Review

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Continuous and Controllable Preparation of Sodium Alginate Hydrogel Tubes Guided by the Soft Cap Inspired by the Apical Growth of the Plant

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ETA‐m‐PAN and its Composite Membrane with High Performance Prepared by In Situ Modification/NIPS Principle

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