Flocculation is regarded as an effective, convenient and promising means for microalgal harvesting of microalgal biomass. In this study three types of metal sulfates (aluminum sulfate, aluminum potassium sulfate and ferric sulfate) were applied as flocculants to harvest microalgae Chlorella vulgaris biomass. The optimal operating parameters such as dosage, rotation speed, flocculation time and sedimentation time during microalgal biomass harvesting were determined, and the effects of metal sulfate application as flocculants on lipid extraction were investigated. The results showed that the optimal dosage for the three flocculants to harvest microalgal biomass was identically 2.5 g L⁻¹, and the optimal rotation speeds for coagulation and flocculation were 150 and 25 rpm, respectively, while the flocculation time of 10 min was found to be appropriate. The findings also suggested that metal residuals in flocculated biomass would affect lipid extraction, resulting in 5.9%, 4.4% and 3.3% reduction of lipid contents for aluminum sulfate, aluminum potassium sulfate and ferrous sulfate, respectively. The contribution of this study lies in the provision of the optimal operating parameters during the microalgal biomass flocculation, thus potentially offering the technical guidance for the harvesting of microalgal biomass using metal sulfates as flocculants in practice.

絮凝被认为是收获微藻生物质的微藻的有效，方便和有前途的手段。在这项研究中，将三种类型的金属硫酸盐（硫酸铝，硫酸铝钾铝和硫酸铁）用作絮凝剂，以收获微藻小球藻生物质。确定了微藻生物质收获过程中的最佳操作参数，如剂量，转速，絮凝时间和沉降时间，并研究了金属硫酸盐作为絮凝剂对脂质提取的影响。结果表明，三种絮凝剂收获微藻生物量的最佳剂量相同为2.5 g L ^-1，絮凝和絮凝的最佳转速分别为150和25 rpm，而絮凝时间为10分钟是合适的。研究结果还表明，絮凝生物质中的金属残留物会影响脂质的提取，分别导致硫酸铝，硫酸铝钾和硫酸亚铁的脂质含量分别降低5.9％，4.4％和3.3％。这项研究的贡献在于在微藻类生物质絮凝过程中提供了最佳的运行参数，从而有可能为在实践中使用金属硫酸盐作为絮凝剂来收获微藻类生物质提供技术指导。