Ghasemian Samaneh, Sahari Mohammad Ali, Barzegar Mohsen, Ahmadi Gavlighi Hasan
Department of Food Science and Technology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.
Department of Food Science and Technology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.
Food Chem. 2017 Sep 1;230:454-462. doi: 10.1016/j.foodchem.2017.02.135. Epub 2017 Mar 1.
In this study, polyvinylidene fluoride (PVDF) and nano-porous silica particle were used to fabricate an asymmetric nano-composite membrane. Silica particles enhanced the thermal stability of PVDF/SiO membranes; increasing the decomposition temperature from 371°C to 408°C. Cross sectional morphology showed that silica particles were dispersed in polymer matrix uniformly. However, particle agglomeration was found at higher loading of silica (i.e., 20 by weight%). The separation performance of nano-composite membranes was also evaluated using the omega-3 polyunsaturated fatty acids (PUFA) concentration at a temperature and pressure of 30°C and 4bar, respectively. Silica particle increased the omega-3PUFA concentration from 34.8 by weight% in neat PVDF to 53.9 by weight% in PVDF with 15 by weight% of silica. Moreover, PVDF/SiO nano-composite membranes exhibited enhanced anti-fouling property compared to neat PVDF membrane. Fouling mechanism analysis revealed that complete pore blocking was the predominant mechanism occurring in oil filtration.
The concentration of omega-3 polyunsaturated fatty acids (PUFA) is important in the oil industries. While the current methods demand high energy consumptions in concentrating the omega-3, membrane separation technology offers noticeable advantages in producing pure omega-3 PUFA. Moreover, concentrating omega-3 via membrane separation produces products in the triacylglycerol form which possess better oxidative stability. In this work, the detailed mechanisms of fouling which limits the performance of membrane separation were investigated. Incorporating silica particles to polymeric membrane resulted in the formation of mixed matrix membrane with improved anti-fouling behaviour compared to the neat polymeric membrane. Hence, the industrial potential of membrane processing to concentrate omega-3 fatty acids is enhanced.
在本研究中，使用聚偏氟乙烯（PVDF）和纳米多孔二氧化硅颗粒制备了一种不对称纳米复合膜。二氧化硅颗粒提高了PVDF/SiO膜的热稳定性，将分解温度从371°C提高到408°C。横截面形态表明二氧化硅颗粒均匀地分散在聚合物基质中。然而，在较高二氧化硅负载量（即20重量%）下发现颗粒团聚。还分别在30°C和4巴的温度和压力下，使用ω-3多不饱和脂肪酸（PUFA）浓度评估了纳米复合膜的分离性能。二氧化硅颗粒使ω-3PUFA浓度从纯PVDF中的34.8重量%提高到含15重量%二氧化硅的PVDF中的53.9重量%。此外，与纯PVDF膜相比，PVDF/SiO纳米复合膜表现出增强的抗污染性能。污垢机理分析表明，完全堵塞孔是油过滤中发生的主要机理。
ω-3多不饱和脂肪酸（PUFA）的浓度在石油工业中很重要。虽然目前的方法在浓缩ω-3时需要高能耗，但膜分离技术在生产纯ω-3PUFA方面具有显著优势。此外，通过膜分离浓缩ω-3会产生具有更好氧化稳定性的三酰甘油形式的产品。在这项工作中，研究了限制膜分离性能的污垢详细机理。将二氧化硅颗粒掺入聚合物膜中导致形成混合基质膜，与纯聚合物膜相比，其具有改善的抗污染行为。因此，膜处理浓缩ω-3脂肪酸的工业潜力得到增强。
