Manipulating membrane surface porosity via deep insight into surfactants during nonsolvent induced phase separation

Kong, Xiaole; Shu, Guiming; Lu, Xiaolong; Wu, Chunrui; Gai, Yu

doi:10.1016/j.memsci.2020.118358

Cited by 32 publications

(21 citation statements)

References 33 publications

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“…[ 21,33 ] The surfactants play an intermediate role of water and the polymer solution. The hydrophilic ends of the surfactants induce water into the polymer solution, [ 18,34 ] thus promoting the mutual diffusion of water and polymer solution. [ 21 ] More importantly, elevating surfactant SA (i.e., ∆γ value decreases) enhances the intermediate role of the surfactants further.…”

Section: Resultsmentioning

confidence: 99%

“…[21] The channel that PEG is leached out of the polymer solution and the channel that water is attracted into the polymer solution during the membrane formation process forms the membrane pores. [34,35] Hence, the surface porosity is improved notably. Meanwhile, beyond −5.50 mN m -1 , with the continuous elevation of surfactant SA (i.e., with the decrease of ∆γ value) the surface porosity of the hollow fibers remains unchanged.…”

Section: Influence Of Surfactant Sa On the Surface Pore Of Pvdf Hfmsmentioning

confidence: 99%

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Improved Desalination Performance of Polyvinylidene Fluoride Hollow Fiber Membranes by the Intermediate Role of Surfactants

Kong

Liu

et al. 2020

Macro Materials & Eng

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Polymer hollow fiber membranes (HFMs) are the core or base membranes of various membrane processes (e.g., ultrafiltration and membrane distillation). Preparing polymer HFMs with higher water flux helps improve the efficiency of the membrane processes. Using pore‐forming additives is the commonly used and efficient method to improve the water flux. The current dilemma is that the conventional methods that increase the amounts or the molecular weight of the additives to improve the water flux usually lead to the decrease in membrane mechanical strength. Herein, different from the conventional research strategy, increasing the surfactant surface activity (SA) is first found to deeply promote the core of nonsolvent‐induced phase separation (NIPS) that of the mutual diffusion between water and dopes. As a result, this method distinctly improves the surface porosity (from 0.8% to 9.7%) and optimizes the pore size distribution of polyvinylidene fluoride (PVDF) HFMs. Benefit from these, the water flux of ultrafiltration (3.1‐fold increase, maximally) and direct contact membrane distillation (2.3‐fold increase, maximally) are increased greatly. Moreover, the mechanical strength is not negatively affected due to the additive amount of small molecule surfactants is constant and small (2.0 wt%).

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Section: Resultsmentioning

confidence: 99%

Section: Influence Of Surfactant Sa On the Surface Pore Of Pvdf Hfmsmentioning

confidence: 99%

Improved Desalination Performance of Polyvinylidene Fluoride Hollow Fiber Membranes by the Intermediate Role of Surfactants

Kong

Liu

et al. 2020

Macro Materials & Eng

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“…The overall porosity of the hollow fiber membranes was measured based on the weighting method (Mansourizadeh & Ismail 2010;Kong et al 2020). To measure weight of the wet samples, three hollow fibers with the length of 50 cm were immersed in distilled water for three days.…”

Section: Characterization Of the Hollow Fiber Membranesmentioning

confidence: 99%

Modification of porous polyetherimide hollow fiber membrane by dip-coating of Zonyl® BA for membrane distillation of dyeing wastewater

Mousavi

Aboosadi

Mansourizadeh

et al. 2021

Water Science and Technology

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Wetting and fouling have significantly affected the application of membrane distillation (MD). In this work, a dip-coating method was used for improving surface hydrophobicity of the polyetherimide (PEI) hollow fiber membrane. An air gap membrane distillation (AGMD) process was applied for treatment of the methylene blue (MB) solution. The porous PEI membrane was fabricated by a dry-wet spinning process and the hydrophobic 2-(Perfluoroalkyl) ethanol (Zonyl® BA) was used as the coating material. From FESEM, the modified PEI-Zonyl membrane showed an open structure with large finger-like cavities. The modified membrane displayed a narrow pore size distribution with mean pore size of 0.028 μm. The outer surface contact angle of the PEI-Zonly membrane increased from 81.3° to 100.4° due to the formation of an ultra-thin coated layer. The pure water flux of the PEI-Zonyl membrane was slightly reduced compared to the pristine PEI membrane. The permeate flux of 6.5 kg/m2 h and MB rejection of 98% was found for the PEI-Zonyl membrane during 76 h of the AGMD operation. Adsorption of MB on the membrane surface was confirmed based on the Langmuir isotherm evaluation, AFM and FESM analysis. The modified PEI-Zonyl membrane can be a favorable alternative for AGMD of dyeing wastewaters.

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“…However, asymmetric membranes prepared by phase inversion usually have dense epidermis and porous sublayers, resulting in low permeability and low‐solute selectivity, which hinders their wide application in industry 21 . In phase transformation technology, the pore size of membrane plays an important role in the performance of membrane, and pore‐forming agent plays a key role in the formation of pore size in asymmetric membrane 22,23 . Polyvinylpyrrolidone (PVP) is a good pore forming agent, which is easily soluble in water and various organic solvents, and has good solubility 24,25 .…”

Section: Introductionmentioning

confidence: 99%

“…21 In phase transformation technology, the pore size of membrane plays an important role in the performance of membrane, and pore-forming agent plays a key role in the formation of pore size in asymmetric membrane. 22,23 Polyvinylpyrrolidone (PVP) is a good pore forming agent, which is easily soluble in water and various organic solvents, and has good solubility. 24,25 Therefore, PVP can be used to modify the membrane structure of PVC and CA to improve membrane permeability.…”

Section: Introductionmentioning

confidence: 99%

Improvement of filtration performance of polyvinyl chloride/cellulose acetate blend membrane via acid hydrolysis

Zhang

Tan

Yao

et al. 2020

J of Applied Polymer Sci

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Based on the hydrophilicity and biodegradability of cellulose acetate (CA), polyvinyl chloride (PVC)/CA blend membrane was prepared by solution comixing and phase transformation method. Then the CA in the blend membrane was partially hydrolyzed under acidic conditions to improve the hydrophilicity of the blend membrane, so as to improve the filtration performance of the PVC/CA blend membrane. The properties of the membranes were systematically characterized by Fourier transform infrared spectroscopy, differential scanning calorimeter, and scanning electron microscopy (SEM). The porosity, water contact angle, pure water flux (PWF), protein retention rate, and mechanical properties of the membrane were measured, and the effect of hydrolysis on the filtration performance of the blend membrane was analyzed.

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Manipulating membrane surface porosity via deep insight into surfactants during nonsolvent induced phase separation

Cited by 32 publications

References 33 publications

Improved Desalination Performance of Polyvinylidene Fluoride Hollow Fiber Membranes by the Intermediate Role of Surfactants

Improved Desalination Performance of Polyvinylidene Fluoride Hollow Fiber Membranes by the Intermediate Role of Surfactants

Modification of porous polyetherimide hollow fiber membrane by dip-coating of Zonyl® BA for membrane distillation of dyeing wastewater

Improvement of filtration performance of polyvinyl chloride/cellulose acetate blend membrane via acid hydrolysis

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