Preparation of Porous Polymer Membrane with Controllable Pore Size via Spray Spinning

Polymer membranes with fixed pore size or narrow pore size distribution can be used for special separation. However, polymer membranes prepared by conventional method usually have wide pore size distribution and the pore size is hard to control. Here we prepared a porous polymer membrane with uniform pore size via spraying a blend of polystyrene (PS) and polyethylene oxide (PEO) on a filtration paper. Dissolving the water-soluble component (PEO) forms the pore and varying the ratios of PEO in the blend controls the pore size. The pore size and size distribution are also affected by processing parameters, such as the flow rate of solution and carrier gas, and gap length. The morphologies of the membrane are observed using scanning electron microscopy (SEM). The novel polymer membrane with controllable and uniform pore size will be used for the separation of solutes with predictable sizes.

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Dehydrogenation of Propane to Propene over Mesoporous ZrO2-Supported VCrO Catalysts

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1008-1009.290 ◽

2014 ◽

Vol 1008-1009 ◽

pp. 290-294

Author(s):

Bao Agula ◽

Si Qin Dalai ◽

Yue Chao Wu

Keyword(s):

Pore Size Distribution ◽

Pore Size ◽

Size Distribution ◽

Mesoporous Structure ◽

Molar Ratio ◽

Impregnation Method ◽

Size Distributions ◽

Tem Analysis ◽

Surfactant Assisted ◽

Uniform Pore Size

Mesoporous ZrO2with narrow mesopore size distributions has been prepared by the surfactant-assisted method of nanoparticle assembly. A series of VCrO/ZrO2catalysts with different V/Cr molar ratio (0.3, 0.6, 1.0, 1.3 and 1.6) were prepared by the wetness impregnation method and characterized by XRD, N2adsorption and TEM techniques. N2adsorption and TEM analysis revealed that the surfactant-assisted method prepared VCrO/ZrO2catalysts have wormhole-like mesoporous structure with uniform pore size distribution. VCrO/ZrO2catalysts have been applied for direct dehydrogenation of propane to propene. The optimistic catalyst was V/Cr-0.6 with highest yield of 41.7% the corresponding conversion of propane was 44.1% and selectivity to propene was 94.5% at 550 °C.

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Preparation of an Ultrafiltration (UF) Membrane with Narrow and Uniform Pore Size Distribution via Etching of SiO2 Nano-Particles in a Membrane Matrix

Membranes ◽

10.3390/membranes10070150 ◽

2020 ◽

Vol 10 (7) ◽

pp. 150

Author(s):

Bushra Khan ◽

Sajjad Haider ◽

Rooha Khurram ◽

Zhan Wang ◽

Xi Wang

Keyword(s):

Pore Size Distribution ◽

Pore Size ◽

Size Distribution ◽

Nano Particles ◽

Coagulation Bath ◽

Inversion Method ◽

Permeate Flux ◽

Membrane Matrix ◽

Etched Membrane ◽

Uniform Pore Size

The UF membrane with a narrow and uniform pore size distribution and a low tendency to foul has significant applications in wastewater treatment. A major hindrance in the preparation of the UF membrane with these features is the lack of a scalable and economical membrane fabrication method. Herein, we devise a new strategy to prepare a high-quality polyvinylidene fluoride/polymethyl acrylate/cellulose acetate (PVDF/PMMA/CA) blend UF membrane via a combination of the etching mechanism with the traditional Loeb–Sourirajan (L-S) phase inversion method. Different concentrations of silicon dioxide (SiO2) nanoparticles (NP) in the membrane matrix were etched by using a 0.2 M hydrofluoric acid (HF) solution in a coagulation bath. This strategy provided the membrane with unique features along with a narrow and uniform pore size distribution (0.030 ± 0.005 μm). The etched membrane exhibits an increase of 2.3 times in pure water flux (PWF) and of 6.5 times in permeate flux(PF), with a slight decrease in rejection ratio (93.2% vs. 97%) when compared to than that of the un-etched membrane. Moreover, this membrane displayed outstanding antifouling ability, i.e., a flux recovery ratio (FRR) of 97% for 1000 mg/L bovine serum albumin (BSA) solution, a low irreversible fouling ratio of 0.5%, and highly enhanced hydrophilicity due to the formation of pores/voids throughout the membrane structure. The aforementioned features of the etched membrane indicate that the proposed method of etching SiO2 NP in membrane matrix has a great potential to improve the structure and separation efficiency of a PVDF/PMMA/CA blend membrane.

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