PSF/PES共混膜的制备与优化

实验以聚砜(PSF)、聚醚砜(PES)为膜材料,N-甲基吡咯烷酮(NMP)为溶剂,水为凝胶剂,采用L-S相转化法制备了复合膜用共混基膜.按照均匀设计方法优化制膜条件,用SPSS软件处理实验结果得到模型方程,方程反映了各种因素及其交互作用对膜透水性能的影响规律,模型计算值与实验值吻合良好.对于给定的PES含量,随着共混物中PSF /PES 总量的增大,优化计算得到的PVP含量和丙酮含量增大,但相应的膜水通量减小.在上述理论指导下,实验制备基膜的纯水通量为290.6 L·m-2·h-1,对牛白蛋白的截留率达到88.2%.     

Construction of membrane formation system with low critical solution temperature for preparing hydrophilic polysulfone membrane via modified reverse thermally induced phase separation process

This paper presents a novel method to construct a membrane formation system featuring a low critical solution temperature (LCST) by incorporating hydroxy terminated hyperbranched polyester (HBPE) into polysulfone (PSF) casting solution. PSF membranes were developed by modified reverse thermally induced phase separation (m-RTIPS) process while the introduction of HBPE improved the hydrophilicity of the membrane. The critical properties of the flat-sheet PSF membranes were discussed in detail. The cloud point decreased as the HBPE concentration was increased. When membranes were prepared via m-RTIPS, the region of bicontinuous finger-like pores in the sublayer gradually broadened. The membranes showed better permeation properties, larger pore size, and better mechanical properties than those of the membranes prepared via non-solvent-induced phase separation (NIPS) process. Furthermore, no matter the enhanced hydrophilicity of membrane or m-RTIPS membrane-forming mechanism was beneficial to the anti-fouling properties. In general, the membrane MPSF-8-b had relatively high flux, good hydrophilicity and excellent mechanical properties at 0.8 wt.% HBPE content, and the pure water flux recovery of the membrane was increased to 55.2%.     

Optimization of electro-blown polysulfone nanofiber mats for air filtration applications

Durable, robust, and hydrophobic air filtration media was produced via electro-blow spinning (EBS) technique using polysulfone (PSU) due to its superior properties. To our knowledge, this is the first optimization study of PSU nanofiber production via EBS technique for air filtration applications. Concentration, air pressure, and voltage were determined as independent variables for the optimization based on “smaller is the better” approach of Taguchi Design of Experiment. The optimized values which supplied the smallest average fiber diameter (AFD) possible were obtained as 13 wt% PSU, 3 bar, and 7.5 kV. The AFD of the sample obtained from the confirmation experiment was calculated as 105 ± 34 nm. Surface morphologies, porosity values, and wettability behaviors of the samples were investigated by using scanning electron microscopy, gravimetric method, and water contact angle measurements, respectively. PSU nanofiber mats exhibited superhydrophobic behavior (water contact angle values up to 159.8°) which is important for various separation processes. Samples prepared at different deposition times (15, 30, 45, and 60 min) were investigated in terms of particle capture efficiency and pressure drop. The 0.3 μm particle filtration efficiency was found to be 98.09% at an expense of 202 Pa pressure drop which would be suitable for various respiratory and HVAC filter applications.     

Asymmetric oxygen-functionalized carbon nanotubes dispersed in polysulfone for CO2 separation

Carbon dioxide separation from flue gases is an important challenge to be faced. Membrane processes are a promising alternative to increase technical and economical constraints once the development of materials with superior characteristics are attained. Integrally asymmetric mixed matrix membranes (MMMs) were prepared by dry/wet phase inversion process of polysulfone (PSF) containing oxygen-functionalized multiwalled carbon nanotubes (MWNT-O). Fourier transform infrared (FTIR) spectroscopy confirmed the presence of MWNT-O in MMMs. Thermal gravimetric analysis (TGA) showed that MMMs are stable up to 150°C. Photomicrographs from scanning electron microscopy (SEM) revealed that MMMs consist of an asymmetric structure with a skin layer supported on a sponge-like substructure. The pore size of the support of MMMs increased with MWNT-O content from 0.4 to 0.8 wt.% and the thickness of the dense layer decreased. However, when the content of MWNT-O increased to 1 wt.%, the pore size decreased, and the dense layer increased. Therefore, MMMs changed CO₂ separation performance. For 1 wt.% MWNT-O loading compared to the neat polymer, CO₂ permeance and CO₂/N₂ selectivity was increased from 1.5 to 2.7 GPU, and from 9.5 to 14.3, respectively.     

磁场诱导低维磁性碳材料对聚砜膜结构及流通特性的影响

目的 在膜的形成过程中，利用磁场力将亲水性磁性碳纳米材料吸引至膜表面，可以在膜表面附加亲水性和磁性，提高膜的渗透通量和截留率，改善膜污染问题。方法 将氧化石墨烯/碳纳米管混合溶液与Fe³⁺和Fe²⁺的混合溶液通入微反应器中预混合后，利用一步水热法引入四氧化三铁(Fe₃O₄)，制备具有优异磁性能的磁性碳纳米材料(MCN)，并将其共混于聚砜(PSF)基底中，采用磁场诱导非溶剂致相分离法(NIPS)制备磁性混合基质膜(PSF/MCN)。对MCN的形貌结构及磁性等进行表征，并通过改变PSF的浓度研究磁场作用下MCN的定向迁移对膜表面形貌结构及性能的影响。结果 亲水性磁性MCN的饱和磁化强度高达53.17 emu/g(1 emu/g=1 A·m²/kg)，表现出超顺磁性，且MCN在磁场作用下向膜表面定向移动。在相同的磁场强度下，不同聚砜浓度的膜表面表现出不同的形貌特征，并在聚砜的质量分数从15%升至17.5%的过程中，膜表面粗糙度的构成由细微密集的波动形貌转变为宽泛的浮动形貌。此外，MC...