Eco-friendly solvents and their mixture for the fabrication of polysulfone ultrafiltration membranes: An investigation of doctor blade and slot die casting methods
Eco-friendly solvents and their mixture for the fabrication of polysulfone ultrafiltration membranes: An investigation of doctor blade and slot die casting methods
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DOI：
10.1016/j.memsci.2020.118510
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发表时间：
2020-11-15
影响因子：
9.5
通讯作者：
Escobar, Isabel C.
中科院分区：
文献类型：
--
作者：
Dong, Xiaobo;Jeong, Tae J.;Escobar, Isabel C.
非溶剂诱导相分离法已广泛应用于聚合物膜的制备。常见溶剂，如二甲基乙酰胺（DMAc）和N-甲基-2-吡咯烷酮（NMP），是有毒的，不环保的;因此，生态友好的替代品是必要的。已经研究了生态友好的溶剂，例如Rhodiasolv（R）PolarClean（PolarClean）和γ-戊内酯（GVL），以在实验室规模上替代DMAc和NMP;然而，在生产规模上没有广泛使用。在这项工作中，制造聚砜（PSF）超滤膜使用环保溶剂在实验室和生产规模的可行性进行了研究。首先，确定了将GVL添加到PolarClean的涂料溶液中可以在450 RPM的旋转速度下将原始制备时间减少三分之二，并且在600 RPM下减少四分之三。此外，涂料溶液表现出牛顿流体行为。分别采用刮刀挤出法和辊对辊（R2 R）系统结合狭缝压铸法制备了实验室规模和生产规模的PSf超滤膜，并对所得膜的结构、形态和操作性能进行了比较，膜的化学结构不受不同溶剂的使用和制备规模的影响。另一方面，横截面图像显示膜的结构是不同的，最可能是由于不同溶剂/共溶剂到非溶剂水中的扩散速率的差异。此外，已经观察到，膜相对于制造工艺的粗糙度值是不同的，这可能是由于所需蒸发时间的差异。所有膜显示相似的操作参数，即，牛血清白蛋白（BSA）过滤过程中的通量下降、渗透性和恢复。因此，该研究表明，使用环保溶剂混合物制造的PSf膜与使用石油衍生溶剂铸造的传统膜相当，并且使用R2 R上的狭缝压铸可扩展。
Nonsolvent induced phase separation has been widely used to fabricate polymeric membranes. Common solvents, such as dimethylacetamide (DMAc) and N-Methyl-2-pyrrolidone (NMP), are toxic and not environmentally friendly; therefore, eco-friendly alternatives are needed. Eco-friendly solvents, such as Rhodiasolv (R) PolarClean (PolarClean) and gamma-valerolactone (GVL), have been investigated to replace DMAc and NMP at the laboratory scale; however, not extensively at the production scale. In this work, the feasibility of fabricating polysulfone (PSf) ultrafiltration membranes using eco-friendly solvents at laboratory and production scales is investigated. First, it was determined that the addition of GVL to dope solutions of PolarClean could reduce the original preparation time at a rotation speed of 450 RPM by two-thirds, and by three-quarters at 600 RPM. Furthermore, dope solutions exhibit Newtonian fluid behavior. Doctor blade extrusion and a roll-to-roll (R2R) system integrated with slot die casting are used to fabricate the PSf ultrafiltration membranes at laboratory and production scales, respectively, and the resulting membranes are compared structurally, morphologically and operationally.The chemical structure of membranes is not affected by the use of different solvents or by the differences in fabrication scale. On the other hand, cross-sectional images show that the structures of the membranes are different, most likely due to differences in diffusion rates between the different solvents/co-solvents into the nonsolvent, water. Furthermore, it has been observed that the roughness values of the membranes relative to the fabrication process is different, possibly due to differences in the required evaporation time. All membranes display similar operational parameters, i.e., flux decline, permeability and recovery, during bovine serum albumin (BSA) filtration. Therefore, this study shows that PSf membranes fabricated using eco-friendly solvent mixtures are comparable to traditional membranes, cast using petroleum-derived solvents, and are scalable using slot die casting on a R2R.