Department of Chemical Engineering, University of Jeddah, Jeddah, Saudi Arabia.
Department of Chemical, Polymer and Composite Materials Engineering, University of Engineering and Technology (New Campus) Lahore, Pakistan.
Chemosphere. 2023 Apr;321:138074. doi: 10.1016/j.chemosphere.2023.138074. Epub 2023 Feb 11.
A clean and sustainable energy source, biogas is widely accessible worldwide. The caloric value of biogas is related to its methane content, and therefore removal of other gases is essential for reaping the benefits of this cleaner resource. In contrast to other classical techniques, membrane technology is relatively new yet extremely promising for methane enrichment. The methane enrichment performance of polymeric membranes is constrained, hence newer material combinations have been investigated to enhance membrane performance. In this study, blend membranes comprised of polyetherimide (PEI) and polyvinyl acetate (PVAc) in varying proportions were prepared by adopting the wet-phase inversion technique. The generated pure, and blend membranes were characterized for the morphological, thermal, and structural study. The interactions of PEI and PVAc in blend samples were verified by FTIR analysis. On the other hand, SEM investigation indicated that the membranes have an anisotropic porous structure with a dense skin layer at the top. Subsequently, a single glass transition temperature (T), as validated by DSC analysis, indicates that the blended polymers are miscible. Furthermore, membranes' performance for gas separation was assessed regarding selectivity and permeance at feed pressures ranging from 2 to 6 bar. The permeation results showed that the CO permeance has increased by 40.47% with the addition of 4 wt % PVAc at 2 bar pressure. Furthermore, ideal selectivity improves as the blend ratio increases; nonetheless, the highest value for CO/CH ideal selectivity was attained with a 2 wt % PVAc addition and at 2 bar pressure, which is approximately 26% greater than the pure PEI membrane. At 4 bar pressure, optimum CO/N selectivity value of 22.50 was achieved. The findings indicate that PVAc is an excellent option for expanding the separation performance of blended polymeric membranes for biogas enrichment.
一种清洁且可持续的能源，沼气在全球范围内广泛存在。沼气的热值与其甲烷含量有关，因此去除其他气体对于利用这种更清洁的资源至关重要。与其他经典技术相比，膜技术相对较新，但对于甲烷浓缩极具应用前景。聚合膜的甲烷浓缩性能受到限制，因此研究了新的材料组合以提高膜性能。在这项研究中，采用湿法相转化技术制备了不同比例的聚醚酰亚胺（PEI）和聚醋酸乙烯酯（PVAc）共混膜。对生成的纯膜和共混膜进行了形态、热和结构研究。FTIR 分析验证了 PEI 和 PVAc 在共混样品中的相互作用。另一方面，SEM 研究表明，膜具有各向异性的多孔结构，顶部有致密的皮层。随后，DSC 分析验证了存在单一的玻璃化转变温度（T），表明共混聚合物是互溶的。此外，还评估了膜在 2 至 6 bar 进料压力下的气体分离性能，包括选择性和渗透性。渗透结果表明，在 2 bar 压力下，添加 4 wt%的 PVAc 可使 CO 渗透率提高 40.47%。此外，随着共混比的增加，理想选择性提高；然而，在添加 2 wt%的 PVAc 和 2 bar 压力下，CO/CH 理想选择性达到最高值，比纯 PEI 膜高约 26%。在 4 bar 压力下，获得了最佳的 CO/N 选择性值 22.50。这些发现表明，PVAc 是扩展用于沼气浓缩的共混聚合物膜分离性能的理想选择。
