One of the most noticeable steps in the microalgae biomass production is the harvesting of cells from a very dilute slurry culture medium, which accounts for 20–30% of the whole process operating cost. In the present study, Chlorella vulgaris microalgae of the Persian Gulf, as a type of stable colloidal particles, were initially cultivated in an f/2 culture medium. The dispersed biomass was then harvested using the methods of autoflocculation–sedimentation in the jar test setup and electrocoagulation–flotation in a laboratory-scale horizontal electrodes’ plexiglass container. In this regard, the affecting factors on their harvesting efficiency were optimized and modelled applying response surface methodology. Considering the autoflocculation–sedimentation process and design of experiments results, the maximum harvesting efficiency of 66.00% was obtained under optimum conditions of pH = 12, mixing rate of 20 rpm, and 30 min sedimentation time. In the electrocoagulation–flotation under the optimum conditions of pH = 8.00 and 4.00 v/cm, DC electric field intensity between aluminium electrodes, the harvesting efficiency of 99.55% was achieved within 6 min. However, under the same operating conditions, for the first time in this study, by replacing the aluminium electrodes with the carbon cloth covered by a thin layer of filter paper as the anode, and the stainless-steel cathode, the 98.00% flotation efficiency was attained. Compared to the aluminium electrodes, the carbon cloth/stainless-steel set exhibited the lowest pollution, due to less electrodes’ corrosion. Chlorella vulgaris microalgae of the Persian Gulf was initially cultivated. Autoflocculation-sedimentation and ECF were used for harvesting of microalgae. Affecting factors on harvesting efficiency were modelled applying RSM. In autoflocculation maximum harvesting was 66.00% at pH=12, within 30 min. In ECF with Al-anode maximum harvesting was 99.55% at pH=9, within 6 min. In ECF with carbon cloth anode harvesting was 98% but fewer ion contamination. Chlorella vulgaris microalgae of the Persian Gulf was initially cultivated. Autoflocculation-sedimentation and ECF were used for harvesting of microalgae. Affecting factors on harvesting efficiency were modelled applying RSM. In autoflocculation maximum harvesting was 66.00% at pH=12, within 30 min. In ECF with Al-anode maximum harvesting was 99.55% at pH=9, within 6 min. In ECF with carbon cloth anode harvesting was 98% but fewer ion contamination.

中文翻译：

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自絮凝-沉淀法和电凝-浮选法从稀浆中收获海洋小球藻微藻的比较研究

微藻生物质生产中最引人注目的步骤之一是从非常稀的浆液培养基中收获细胞，这占整个过程运营成本的 20-30%。在本研究中，波斯湾的普通小球藻微藻作为一种稳定的胶体颗粒，最初在 f/2 培养基中培养。然后使用罐测试装置中的自絮凝-沉淀和实验室规模水平电极的有机玻璃容器中的电凝聚-浮选方法收获分散的生物质。在这方面，应用响应面方法对影响其收获效率的因素进行了优化和建模。考虑到自絮凝沉淀过程和实验结果设计，最大收获效率为 66。在pH = 12、混合速率为20 rpm、沉降时间为30分钟的最佳条件下获得00%。在pH = 8.00和4.00 v/cm的最佳条件下的电凝-浮选中，铝电极之间的直流电场强度在6分钟内达到99.55%的收获效率。然而，在相同的操作条件下，本研究首次将铝电极换成覆盖有一层薄薄滤纸的碳布作为阳极，不锈钢阴极，浮选效率达到98.00%。达到。与铝电极相比，碳布/不锈钢电极组的污染最低，因为电极的腐蚀较少。最初栽培波斯湾的普通小球藻微藻。自絮凝沉淀和 ECF 用于收获微藻。应用 RSM 对影响收获效率的因素进行建模。在自絮凝中，在 pH=12 时，30 分钟内的最大收获率为 66.00%。在具有铝阳极的 ECF 中，在 pH=9 时，6 分钟内的最大收获率为 99.55%。在带有碳布阳极的 ECF 中，收集率为 98%，但离子污染较少。最初栽培波斯湾的普通小球藻微藻。自絮凝沉淀和 ECF 用于收获微藻。应用 RSM 对影响收获效率的因素进行建模。在自絮凝中，在 pH=12 时，30 分钟内的最大收获率为 66.00%。在具有铝阳极的 ECF 中，在 pH=9 时，6 分钟内的最大收获率为 99.55%。在带有碳布阳极的 ECF 中，收集率为 98%，但离子污染较少。