多孔磁性纳米材料的构筑及其响应行为对吸附效率的作用机制研究

Adsorptive desulfurization is a promising technology featured with ambient operation conditions, low reduction of octane number, and low cost, which exhibits a great prospect for deep desulfurization of fuels. However, the present researchers mainly focus on improving capacity and selectivity of adsorbents, neglecting the balance of the overall efficiency of adsorptive desulfurization. In order to solve the problem of low efficiency in adsorption and separation process, this project plans to fabricate magnetically porous nanobars as adsorbents and further establish a novel mode of magnetically controllable adsorption process, including the magnetically responsive self-stirring of adsorbents and the magnetically induced recycling. On the one hand, this new mode creatively integrates the function of stirring to the adsorbent itself for achieving the high-speed self-rotation and self-diffusion of adsorbents under the rational magnetic field. As a result, the nanoscale stirring can be reached to improve the efficiency of external diffusion, which may break the limitation of the conventional stirring method; on the other hand, the magnetically induced recycling can also be integrated. By exploiting the magnetic field, the solid-liquid separation can be conveniently and efficiently completed, and the recovery time and mass loss of adsorbents can be greatly reduced. The expected achievements can provide theoretical basis and technical guidance for the development of novel adsorbents for deep desulfurization and the innovation in modes of adsorption and separation process.

吸附脱硫技术具有操作条件温和、辛烷值损失小和成本低等优点，在燃料油的深度脱硫中具有广阔的应用前景。然而目前研究者的工作主要集中于提高吸附剂的吸附量和选择性，忽视了对吸附脱硫工艺整体效率的兼顾。本项目以解决吸附分离过程面临的低效率问题为目标，拟构筑一种具有磁响应性的多孔纳米棒吸附剂并建立新型的磁控制吸附分离模式，主要包括吸附剂的磁响应自搅拌和磁回收过程。这种新型吸附分离模式一方面打破了常规搅拌手段的限制，创新性地将搅拌功能赋予吸附剂本身，利用外部磁场的控制完成吸附剂的高速自旋转和自扩散，从而实现纳米级别的搅拌以达到提高外扩散效率的目的；另一方面集成了吸附剂的磁回收功能，利用磁场的诱导实现固液两相便捷、高效的分离，在减少回收时间的同时还能够降低吸附剂的质量损失。研究成果可以为新型脱硫吸附剂的开发和吸附分离模式的创新提供理论依据与技术指导。

吸附脱硫过程在液相中进行，因此传质过程和吸附剂的回收关系着吸附工艺的效率。传统的处理方式包括搅拌、离心和过滤等操作，难以达到便捷、高效的要求。本项目首先将多孔材料磁响应纳米颗粒复合，设计了多种制备策略（例如浸渍法、溶胶凝胶法和蒸汽诱导法），实现了介孔硅、多孔碳以及金属有机框架等不同类别的磁响应复合吸附剂的构筑。考察了制备参数对材料形貌、结构性质以及表面化学的影响，阐明了吸附剂的制备机理。接着研究了材料的磁响应性质以及在外部磁场作用下的响应行为，实现了其在宏观溶剂以及微观液滴中的磁响应搅拌和扩散功能，揭示了其中的运行机制，构建了磁控制吸附分离模式。然后系统评价了吸附剂的性能，通过多种表征手段阐明了吸附机理，剖析了材料的构效关系，通过动力学研究证实了磁响应搅拌对吸附过程的促进作用。最后将磁响应纳米棒材料推广至非均相催化中，在纳米颗粒表面成功引入了不同的活性位点，例如贵金属Ag、Au和强碱性位，应用于不同的催化反应，实现了催化剂的磁响应多功能集成。项目揭示了功能型磁响应纳米材料的合成机制，实现了其在液相吸附和非均相催化中的应用，为新型吸附/催化材料的设计和开发提供理论指导和实验依据。