Elucidation of Dynamics in Advanced Separation of Soft Colloid

近年来，颗粒-流体分离技术在生物技术、生物质工业、功能食品、生物医药、生物有机体等领域得到了广泛的应用。因此，对易变形、难分离的微生物、凝胶颗粒、乳状液、生物大分子、团聚颗粒等软胶体的先进分离技术的发展迫在眉睫。本研究的主要目的是阐明软胶体分离动力学。以微生物、水凝胶、乳状液为样品进行过滤、表达、沉淀、离心。确定了对分离性能有显著影响的颗粒的分离行为、变形特征以及颗粒(饼和沉淀物)胶状聚集体的性质。结果表明，由软胶体组成的滤饼和沉淀物具有极高的可压缩性。研究还表明，由于软颗粒在固体压缩压力作用下的变形，软胶体的滤饼和沉淀物呈现出小于未变形球体的六角形紧密堆积的孔隙率。因此，优选在相对较低的压力下进行软胶体的分离，因为压力的增加不一定导致分离性能的改善。这些发现为优化操作的设计和新型分离技术的开发提供了有价值的信息，并将极大地促进与软胶体分离相关的各个领域的发展。

In recent years, particle-fluid separation such as filtration, expression, sedimentation and centrifugation is becoming widely accepted in such diversified fields as the biotechnology, biomass industry, functional food, biomedicine, living organism. Therefore, development of advanced separation technology for soft colloids such as microorganism, gel particle, emulsion, biomacromolecule, agglomerated particle, which are deformable and difficult-to-separate particles, is strongly desired.The main purpose of this research is to clarify the dynamics of separation of soft colloids. Filtration, expression, sedimentation and centrifugation were conducted using microorganism, hydrogel, emulsion as test sample. We have ascertained separation behaviors, deformation characteristic of particles and the properties of gelatinous aggregates of particles (cake and sediment) which had a significant influence on separating function. It was revealed that the filter cake and sediment composed of soft colloids have extremely high compressibility. It was also shown that the cake and sediment of soft colloids exhibited the porosity which was less than hexagonal close packing of undistorted spheres because of the deformation of the soft particles under the action of the solid compressive pressure. Consequently, it is preferred that separation of soft colloids is conducted under the relatively low pressure since the increase in the pressure does not necessarily lead to the improvement of the separation properties. These findings provide a valuable information for design of optimum operation and development of novel separation technology, and will be greatly contributed to advancement of diverse fields associated with separation of soft colloids.