能源微藻表面特性对其气浮采收效率的影响

选取小球藻与鱼腥藻为代表藻种,结合微藻的表面特性与XDLVO理论,研究了影响微藻浮选采收的关键因素,根据微藻表面的电负性,用阳离子表面活性剂C16TAB浮选两种藻.结果表明,pH为4~10时,两种藻的Zeta电位在-6.72~-15.01 m V之间,均显电负性;小球藻的黏附自由能为1.21 m J/m2,显亲水性,鱼腥藻的黏附自由能为-55.85 m J/m2,显疏水性.相同条件下,疏水性的鱼腥藻回收率始终高于亲水性的小球藻.小球藻和鱼腥藻在Zeta电位最大的pH处(分别为7和8)富集比最高(分别为12.45和1.3),而回收率在pH=10时最高,表明由于液膜的排液行为,回收率和富集比无法同时达到最大值.C16TAB对微藻表面疏水性有修饰作用,加入80 mg/L C16TAB后,小球藻疏水率从19%提高到64%,回收率提高了67.38%.

Influences of Surface Characteristics of Energy Microalgae on Its Harvesting Performance by Air Flotation

Two algal species Chlorella vulgaris and Anabaena vasriabilis were chosen as typical energy microalgae to investigate the surface characteristics of microaglae. The surface potential and hydrophobicity was examined based on the extend XDLVO theory. According to the Zeta potential, hexadecyl trimethyl ammonium bromide (C16TAB) was used as cationic surfactant for flotation. The results showed that both two strains carried with negative charge, and free energy of cohesion for C. vulgaris was 1.21 mJ/m2, and ?55.85 mJ/m2 for A. varsriabilis, which meant hydrophilicity and hydrophobicity respectively. A. varsriabilis performed better harvesting rate than C. vulgaris. The maximums concentration factor (12.45 for C. vulgaris and 1.3 for A. varsriabilis) toped at the pH which charged most negatively (pH=7 for C. vulgaris and pH=9 for A. varsriabilis). Nevertheless, harvesting rate toped at pH=10, which meant it could not reach the maximum with the concentration factor in the same condition, may owing to the drainage of the tonoplast. Meanwhile, after adding 80 mg/L C16TAB into the algal solution, the hydrophobicity rate for C. vulgaris raised from 19% to 64%, and the harvesting rate increased by 67.38%.