Fe_(3)O_(4)@植物多酚收集微藻的磁泳过程机制研究

Magnetophoresis Process Mechanism of Harvesting Microalgae by Use of Fe_(3)O_(4)@Plant-Polyphenol

文章利用植物多酚作为功能化材料和调控配体,一步自组装制备出Fe_(3)O_(4)@植物多酚(Fe_(3)O_(4)@PP)收集产油微藻,通过粒子图像测速技术(PIV)对Fe_(3)O_(4)@PP收集产油微藻的磁泳流场演化进行了研究,并采用光学显微镜图像技术对磁藻聚集体形态进行了观测。在不同Fe_(3)O_(4)@PP投加量和不同磁场强度条件下,测试了磁收集过程的容器纵截面的流场数据和演化特征。结果表明,磁藻聚集体在磁场作用下会在近磁铁端形成涡流区,并经历加速、平缓和减缓3个阶段的运动规律,流速随Fe_(3)O_(4)@PP投加量的增加而增大,随磁场强度的减弱而减小,磁泳时间随磁场强度的减弱而延长。采用光学显微镜观测磁藻聚集体形态在搅拌和磁收集阶段的变化,发现在搅拌剪切力作用下Fe_(3)O_(4)@PP与微藻细胞碰撞形成小尺寸磁藻聚集体,并在磁力作用下聚集形成链簇微结构,磁藻聚集体在成链簇和运动过程中进一步碰撞并结合藻细胞以及链簇密集时网捕扫掠游离藻细胞从而完成微藻的磁收集。

This paper described a bench-scale experimental study, which was involving plant polyphenol that was chosen as functional materials and regulatory ligands, as well as the one-step self-assembly to prepare a sort of plant polyphenols(Fe_(3)O_(4)@PP) for harvesting oleaginous microalgae. The magnetophoretic flow field of the oleaginous microalgae harvest by use of Fe_(3)O_(4)@PP was studied with particle image velocimetry(PIV), and the morphology of magnetic aggregates was detected with optical microscope image technology. The flow field data and characteristics in longitudinal section of the container in the magnetic harvesting process were tested under the conditons of different Fe_(3)O_(4)@PP dosages being added and of the different magnetic field intensities being exerted. As a result, the experimental study showed that the magnetic algae aggregate formed an eddy current region near the magnet, and experienced three stages of acceleration, stabilization and deceleration;in addition, increasing the dosage of Fe_(3)O_(4)@PP could increase the flow velocity, and the flow velocity would decrease with the decline of magnetic field intensity;and the magnetophoresis time prolonged with the decrease of magnetic field intensity. In addition, the variation of the morphology of magnetic algae aggregates during the stirring and magnetic harvesting stages was observed using optical microscope. It was found that Fe_(3)O_(4)@PP collided with microalgae cells to form small-size aggregates under the action of stirring shear force, and it further gathered to form chain cluster microstructure under the action of magnetic force. Then the aggregates collided and were combined with microalgal cells in the process of cluster formation and movement, which also netted and swept free microalgal cells when clusters were dense, thus achieving magnetic microalgal harvesting.