CTS@Fe_(3)O_(4)-COOH对低pH值Chlorella vulgaris采收性能及机理

The harvesting performance and mechanism of CTS@Fe_(3)O_(4)-COOH on low pH Chlorella vulgaris

采用共沉淀法制备得到磁性材料壳聚糖@柠檬酸改性Fe_(3)O_(4)(CTS@Fe_(3)O_(4)-COOH),通过单因素与正交试验考察了不同条件下其对小球藻(Chlorella vulgaris)的采收效率.结合XRD、FT-IR和VSM等材料的结构性质表征、表面Zeta电位及Derjaguin-Landau-Verwey-Overbeek(DLVO)理论分析,探讨CTS@Fe_(3)O_(4)-COOH对小球藻的絮凝采收机理.结果表明,CTS@Fe_(3)O_(4)-COOH对小球藻具有高效采收效率,与未改性相比采收效率提高约30%.单因素试验表明材料投加量与pH值对小球藻采收效率的影响较大;正交试验表明当CTS@Fe_(3)O_(4)-COOH投加量为4.5g/L时,在pH 4的条件下,经500r/min快搅3min后再70r/min慢搅5min,对小球藻的采收效率高达98.35%.DLVO等理论分析表明,CTS@Fe_(3)O_(4)-COOH对小球藻的采收机理为电荷中和、静电修补、吸附架桥与整体絮凝联合作用.本文结果为CTS@Fe_(3)O_(4)-COOH采收固定烟气能源微藻的实际应用提供数据支持.

The magnetic material chitosan@citric acid modified Fe_(3)O_(4)(CTS@Fe_(3)O_(4)-COOH)was synthesized by co-sedimentation method.The harvesting efficiency of Chlorella vulgaris under different conditions was investigated by single-factor and orthogonal tests.The combination with the structural property characterization of XRD,FT-IR and VSM,surface Zeta potential and the Derjaguin-Landau-Verwey-Overbeek(DLVO)theory analysis to investigate the flocculation harvesting mechanism of CTS@Fe_(3)O_(4)-COOH on Chlorella vulgaris.The results implied that CTS@Fe_(3)O_(4)-COOH had high harvesting efficiency for Chlorella vulgaris,with an increase in harvesting efficiency of about 30%compared to unmodified.The single-factor test showed that the magnetic material dosage and pH had a greater effect on the harvesting efficiency of Chlorella vulgaris.The orthogonal test showed the best flocculation conditions of investigated variables were:4.5g/L of CTS@Fe_(3)O_(4)-COOH,pH=4,rapid stirring at 500r/min in 3min,slow stirring 70r/min in 5min and the harvesting efficiency can reach 98.35%.Theoretical analyses such as DLVO suggested the harvesting mechanisms of CTS@Fe_(3)O_(4)-COOH on Chlorella vulgaris were charge neutralization,electrostatic path,adsorption bridging and sweeping flocculation.The results provide data support for the practical application of CTS@Fe_(3)O_(4)-COOH harvesting of fixed flue gases from energy microalgae.