Development of novel layer-by-layer assembled nanofiltration hollow fiber membranes for water treatment

Hollow fiber membranes are of great commercial interest with several applications at the forefront of research to carryout bioseparations, drinking water purification, wastewater treatment besides liquid phase separations and gaseous separations. An experimental study was carried out to synthesize hollow fiber membranes from polyethersulfone (PES) and polyacrylonitrile (PAN) polymers to fabricate modules for surface water treatment and clarification of fungal enzyme broth. Design drawings of a manual hollow fiber spinning machine and spinneret were prepared to fabricate the necessary equipment for extrusion of hollow fibers. Effect of various spinning conditions on specific macroscopic fiber properties, such as outer diameter and wall thickness and membrane pore structure was studied. Concentrations of 15–20 wt% PES in n-methylpyrrolidone (NMP) and PAN in dimethyl formamide (DMF) solvents with important additives and pore formers were prepared. These polymer solutions were extruded through the spinneret and subjected to phase inversion in a water bath. The membranes were characterized by scanning electron microscopy (SEM) and pure water flux studies. PAN and PES exhibited 99.8 and 95.4% turbidity rejection. PAN exhibited a 5 log reduction of Escherichia coli bacteria for surface water treatment at a low hydraulic pressure of 1 bar with a flux of 54.2 L/m2 h at a water recovery of 80% whereas PES gave a flux of 36.6 L/m2 h with 4 log reduction of E. coli. PAN and PES membranes exhibited 54.9 and 69.3% xylanase enzyme recoveries from fungal broth at reasonable flux with turbidity rejection of 94.8 and 95.7% respectively.

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Preparation for PTFE Hollow Fiber Membranes Used in Water Treatment and Optimization for its Extrusion Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.750-752.828 ◽

2013 ◽

Vol 750-752 ◽

pp. 828-831 ◽

Cited By ~ 1

Author(s):

Chao Zhuang ◽

Zhi Qing Luo ◽

Wen Qing Chen

Keyword(s):

Water Treatment ◽

Hollow Fiber ◽

Retention Rate ◽

Pure Water ◽

Water Flux ◽

Chemical Properties ◽

Hollow Fiber Membranes ◽

High Fracture ◽

Processing Methods ◽

Fiber Membranes

For their excellent physical and chemical properties, PTFE hollow fiber membranes can be used in harsh environment of water treatment. But the membranes cannot be prepared by conventional methods, such as the melting processing methods and the dry-wet spinning processing methods, because of a high melting point of 327°C and chemical stability. In this paper a method of extrusion-stretching-sintering is used, and using this method we get the membranes with high fracture strength (10MPa) and high pure water flux (1500L/(m2*h)), also the retention rate of bovine serum albumin reaching 50%, which meets the laboratory microfiltration membrane requirements.

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Surface Modified Polysulfone Hollow Fiber Membranes for Ethane/Ethylene Separation Using Gas-Liquid Membrane Contactors with Ionic Liquid-Based Absorbent

Fibers ◽

10.3390/fib7010004 ◽

2019 ◽

Vol 7 (1) ◽

pp. 4 ◽

Cited By ~ 6

Author(s):

Margarita Kostyanaya ◽

Stepan Bazhenov ◽

Ilya Borisov ◽

Tatiana Plisko ◽

Vladimir Vasilevsky

Keyword(s):

Hollow Fiber ◽

Liquid Membrane ◽

Membrane Contactor ◽

Layer By Layer ◽

Hollow Fiber Membranes ◽

Acrylic Copolymer ◽

Promising Alternative ◽

Silver Salts ◽

Fiber Membranes ◽

Membrane Contactors

Olefin/paraffin separation is an important technological process. A promising alternative to conventional energy-consuming methods is employment of gas-liquid membrane contactors. In the present work, the membranes used were polysulfone (PSf) asymmetrical porous hollow fibers fabricated via the NIPS (non-solvent induced phase separation) technique in the free spinning mode. The surface of the fine-pored selective layer from the lumen side of the fibers was modified by layer-by-layer deposition of perfluorinated acrylic copolymer Protect Guard® in order to hydrophobized the surface and to avoid penetration of the liquid absorbent in the porous structure of the membranes. The absorbents studied were silver salts (AgNO3 and AgBF4) solutions in five ionic liquids (ILs) based on imidazolium and phosphonium cations. The membranes were analyzed through gas permeance measurement, SEM and dispersive X-ray (EDXS). Contact angle values of both unmodified and modified membranes were determined for water, ethylene glycol, ILs and silver salts solutions in ILs. It was shown that the preferable properties for employment in membrane contactor refer to the PSf hollow fiber membranes modified by two layers of Protect Guard®, and to the absorbent based on 1 M AgNO3 solution in 1-ethyl-3-methylimidazolium dicyanamide. Using the membrane contactor designed, ethylene/ethane mixture (80/20) separation was carried out. The fluxes of both components as well as their overall mass transport coefficients (MTC) were calculated. It was shown that the membrane absorption system developed provides absorption of approx. 37% of the initial ethylene volume in the mixture. The overall MTC value for ethylene was 4.7 GPU (gas permeance unit).

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