微藻絮凝和沉淀：pH 值和钙离子浓度影响的时空评价。
Microalgal flocculation and sedimentation: spatiotemporal evaluation of the effects of the pH and calcium concentration.
机构信息
Graduate School of Engineering, Soka University, 1-236 Tangi-machi, Hachioji City, Tokyo, 192-8577, Japan.
Institute of Plankton Eco-Engineering, Soka University, 1-236 Tangi-machi, Hachioji City, Tokyo, 192-8577, Japan.
出版信息
Bioprocess Biosyst Eng. 2022 Sep;45(9):1489-1498. doi: 10.1007/s00449-022-02758-0. Epub 2022 Aug 3.
The high cost of harvesting microalgae is a major hurdle for the microalgae industry, and an efficient pre-concentration method is required. In this study, the effects of using different pH values (between pH 3 and 11) and calcium (Ca) concentrations (between 0 and 5 mM) on Chlorella vulgaris sedimentation were investigated by evaluating the spacio-temporal distributions of microalgae cells. Fast and efficient sedimentation occurred (within 10 min) at a high Ca concentration (5 mM) at pH 9 and 11. However, the sediment volume was lower at a Ca concentration of 3 mM than at a Ca concentration of 5 mM. This indicated that the Ca concentration strongly affected the sediment volume. Fast sedimentation and a low sediment volume were found at pH 7 and a Ca concentration of 5 mM, probably because of the neutral charge in the system (adhesion to calcium precipitates would have occurred at a high pH). The highest Ca recovery (82%) was achieved when sediment produced at pH 11 and a Ca concentration of 5 mM was acidified to pH 3.
藻种收获成本高是微藻产业面临的主要障碍，需要一种高效的预浓缩方法。本研究通过评估微藻细胞的时空分布，考察了不同 pH 值（3 至 11）和钙离子浓度（0 至 5mM）对小球藻沉淀的影响。在 pH 值为 9 和 11 时，钙离子浓度为 5mM 时，藻种能够快速高效地沉淀（在 10 分钟内完成）。然而，钙离子浓度为 3mM 时的沉淀体积小于钙离子浓度为 5mM 时的沉淀体积。这表明钙离子浓度强烈影响沉淀体积。在 pH 值为 7 和钙离子浓度为 5mM 时，发现沉淀速度快且沉淀体积小，这可能是由于系统带中性电荷（在高 pH 值下会发生与钙沉淀物的黏附）。当将在 pH 值为 11 和钙离子浓度为 5mM 条件下产生的沉淀酸化至 pH 值 3 时，可实现最高 82%的钙离子回收率。
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