8种不同絮凝剂对埃氏小球藻絮凝效应的研究

Eight different flocculants study of Chlorella emersonii flocculation effect

[目的]建立简易高效收集能源微藻的技术体系。[方法]以埃氏小球藻(Chlorella emersonii)为目标藻株,选取金属盐类(氯化铁、硫酸铁、氯化铝、硫酸铝钾,)、碱类(氢氧化钠、氢氧化钙)和有机高分子化合物类(聚丙烯酰胺、壳聚糖)为絮凝剂比较分析其在小球藻采收时絮凝效率和相应的絮凝条件。[结果]综合考虑絮凝效果和絮凝剂用量,这8种絮凝剂里硫酸铁、硫酸铝钾,氢氧化钙和氢氧化钠可以有效地絮凝小球藻,具体结果为:静置80min,硫酸铁浓度为0.3g·L-1,絮凝效率为95%;硫酸铝钾浓度为0.7g·L-1,絮凝效率95%;氢氧化钙浓度为0.5g·L-1,絮凝效率97%;氢氧化钠浓度为0.9g·L-1,絮凝效率93%。[结论]综合成本、絮凝效率、环境影响等因素,氢氧化钙是最佳的采收小球藻的絮凝剂,其最佳絮凝条件为藻液pH=8,OD680=1.2,搅拌速率150r·min-1,搅拌时间2min。

[Objective]Flocculation was distinguished as a promising method in microalgae harvest for its low cost and easy operation. For the establishment of a simple and efficient system to collect microalgae. [Methods]Eight flocculant including metal salts （ferric chloride, ferric sulfate, aluminium chloride and aluminium potassium sulphate）, alkaline （sodium hydroxide and calcium hydroxide）, and organic polymer compounds （polyacrylamide and chitosan）, were cho- sen to flocculate Chlorella emersonii in this study, moreover, the flocculated efficiency using different flocculants and appropriate conditions were explored. [Results]Ferric sulfate, aluminium potassium sulphate, sodium hydroxide and calcium hydroxide were effective flocculant for microalgae flocculation considering their flocculation efficiency and con- sumption. The flocculation efficiency could reached 95% after 80 minutes standing with 0. 3 g L -1 ferric sulfate or 0.7 g L-1 aluminium potassium sulphate. When using calcium hydroxide and sodium hydroxide as flocculants, the floccula- tion efficiency achieved 97% and 93% with the concentration of 0.5 and 0. 9 g L-1 respectively. [Conclusion]In view of efficiency, cost and environmental, effect in Chlorella floceulation, calcium hydroxide was selected as the optimal floe- culant and other experimental conditions were also optimized then. Results indicated that optimum conditions for floc- culation were pH =8, algae solution OD680 =1.2, stirring speed 150 r min-1 and mixing time 2 min.