CTS@Fe3O4-COOH对低pH值Chlorella vulgaris采收性能及机理

采用共沉淀法制备得到磁性材料壳聚糖@柠檬酸改性Fe₃O₄(CTS@Fe₃O₄-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@Fe₃O₄-COOH对小球藻的絮凝采收机理.结果表明,CTS@Fe₃O₄-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@Fe₃O₄-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@Fe₃O₄-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@Fe₃O₄-COOH采收固定烟气能源微藻的实际应用提供数据支持.

The harvesting performance and mechanism of CTS@Fe3O4-COOH on low pH Chlorella vulgaris

The magnetic material chitosan@citric acid modified Fe₃O₄ (CTS@Fe₃O₄-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@Fe₃O₄-COOH on Chlorella vulgaris. The results implied that CTS@Fe₃O₄-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@Fe₃O₄-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@Fe₃O₄-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@Fe₃O₄-COOH harvesting of fixed flue gases from energy microalgae.