原位气浮藻水分离过程中改性剂-气泡-藻细胞间界面作用机制研究

The seasonal algal bloom in eutrophic water seriously affects the ecosystem and threatens the safety of drinking water. According to our previous study, efficient on-site separation of algae-water could be achieved by the application of functional bubbles, and this technology may be applied for the emergency treatment of algal bloom. However, the mechanisms of interfacial interaction between the modifier-bubble-algal cell are still not clear, which restricts the application of on-site flotation for the bloom control. In this study, the interfacial interaction mechanism between the modifier and bubble will be explored based on the adsorption properties of the modifier on the bubble surface using Al-NMR technique, and the quantitative relationship between the surface properties of functional bubble and dosage of modifiers will be developed. To reveal the mechanism driving the attachment between functional bubble and microalgae cell, a high-speed micro visualization system will be employed to study the attachment behavior, and the attachment and detachment force between functional bubble and cell will be quantified using AFM. Furthermore, the regulating strategies for the enhancement of interface interactions between modifier-bubble, functional bubble-algal cells will be developed for efficient and cost effective on-site algal flotation. This study will provide critical information to break through the technical bottlenecks of on-site algal flotation by strengthen the modifier-bubble-cell surface interaction for the efficient algal cell capture, and thus promote the application of on-site flotation for algae bloom control.

富营养化水体中藻类的季节性暴发严重影响水生生态系统，也威胁到广大群众的饮用水安全。我们前期的研究发现利用功能化气泡可以实现藻水的原位气浮分离，该技术有望应用于藻类水华的应急处理。然而原位气浮藻水分离过程中改性剂-气泡-藻细胞间的界面作用机制尚不明晰，制约了原位气浮在藻类水华控制上推广应用。本项目拟通过Al-NMR等手段研究改性剂在气泡表面的吸附特性，及其与气泡表面性质间的定量关系，揭示改性剂对气泡功能化修饰的作用机理；通过可视化气泡-藻细胞粘附行为测试系统、AFM界面力学分析等手段研究功能化气泡与藻细胞间的粘附行为和力学特性，明确功能化气泡-藻细胞间的粘附驱动机制；在此基础上构建原位气浮藻水分离过程中的界面作用的强化调控策略。该研究有望突破原位气浮藻水分离的技术瓶颈，实现气泡的定向功能化修饰，强化气泡对藻细胞的捕集能力，推进原位气浮这一新技术在藻类水华应急处理上的推广应用。

富营养化水体中藻类的季节性暴发严重威胁到水生生态系统健康和广大群众的饮用水安全，原位气浮技术可以实现水体中藻类的快速原位清除，可有效解决藻类水华带来的水环境问题。本项目系统研究了藻细胞原位气浮的影响因素及其作用规律，探索了改性剂在气泡表面的吸附特性及其作用后气泡表面性质的响应，搭建了藻细胞-气泡间作用的可视化研究系统，解析了功能化气泡粘附藻细胞的驱动机制。主要结论有：探明了藻源有机物是影响藻细胞原位气浮的关键因子，其组成组分中的由糖醛酸构成的多糖分子上的羧基由于静电作用会与藻细胞竞争改性剂的正电荷位点，降低藻细胞与气泡间的作用，从而抑制原位气浮效率；Al3+类改性剂主要以无定形态吸附在气泡上，使气泡被改性成正电性，且可通过相互间桥接，使其具有网捕藻细胞的性能；溶液中的正电性金属离子会通过竞争吸附作用影响改性剂在气泡上的吸附，且会阻碍气泡液膜排液，从而影响原位气浮性能；改性剂通过静电作用或疏水作用会优先吸附在气泡上，使气泡表面带正电性，然后再通过静电作用与藻细胞直接粘附，从而实现藻细胞原位气浮。基于上述研究，本项目开发了基于原位气浮的藻类清除系统，并成功在南水北调等饮用水源进行示范与应用，可实现水体中90%以上的藻类原位清除。本项目为藻类原位气浮技术的推广应用奠定了理论基础，为解决水体中藻类水华提供了新的解决方案，对保障水生态健康和饮用水安全具有重要意义。