| 摘要 | In order to develop efficient membrane based harvesting techniques to accelerate microalgal commercialization, macrofiltration membranes of mixed cellulose with pore sizes of 0.45, 1.2, 3, 5, and 8 mu m were evaluated for Scenedesmus acuminatus harvesting. The influences of pore size on the changes in membrane flux and flux recovery were investigated, followed by a SEM analysis of the fouled membranes. The performance of S. acuminatus harvesting using the 5 mu m membrane was then compared with an ultrafiltration membrane, with both operating under a cross-flow mode. Macrofiltration operated with dead-end mode was further developed to achieve higher flux and higher solid content in the harvested biomass. The results showed that the 5 mu m mixed cellulose membrane achieved the highest average flux due to its excellent anti-fouling performance. SEM images revealed that the presence of non-cellular and cellular foulants were responsible for the fouling of the smaller sized membranes, and membranes larger than 5 mu m, respectively. Macrofiltration membrane harvesting was more efficient when a dead-end rather than a cross-flow operation was used. The average flux from a multiple - times filtration cycle reached 1845 +/- 105 L.m(-2).h(-1) for the dead-end operated 5 mu m macrofiltration membrane, which was 16-fold higher than that obtained using a cross-flow ultrafiltration membrane (107 +/- 14 L.m(-2).h(-1)). The solid content of macrofiltration-harvested biomass was 24%. This high flux and high solid content achieved through macrofiltration represents a great leap towards high-efficiency microalgal harvesting. |
