纳米气泡协同纳米铁去除水体中污染物的界面过程与增强机制研究

Nanobubbles have very broad application prospects in the environment area due to such properties as large specific surface area, surface energy and internal energy which make it can strengthen the surface reaction and improve the efficiency of mass transfer, and the nano-sized bubble can stable exist in the environment and without secondary pollution. Combined with the characteristics of the nanobubbles and nanoscale iron particles, the project put forward to develop methods about in situ generated nanobubbles layer coated on surface of nanoscale iron particles and characterize of the morphology, size, shape composition, stability and interfacial properties of the nano materials. The research mainly focus on study of the nanobubbles layer's influence on nanoscale iron particles’ activity and stability and explore the new way of stabilization of metal nanoparticles in the environmental medium. In this work, the mechanism of nanobubbles enhanced nanoscale iron particles adsorption and degradation pollutants and reaction kinetics were studied, heavy metals (chromium and arsenic) and organochlorine (TCE)pollutants were used as the model pollutants, different environmental impact factors were considered. The study will provide theoretical and technological support for the development of new environmental nanotechnology.

纳米气泡具有比表面积大、表面能大及气泡内能大特点，可以加强表面反应,提高传质效率，同时纳米级气泡能够稳定存在，且无二次污染，将其引入环境领域具有非常广阔的应用前景；本项目提出结合纳米气泡和纳米铁的特性，在纳米铁表面原位生成纳米气泡包覆层，并表征其形貌、尺寸、形态组成、稳定性及界面性能，重点研究纳米气泡包覆层对纳米铁活性及稳定性的影响，从而探索纳米金属颗粒在环境介质中稳定化的新途径；选择重金属（砷和铬）和有机氯（三氯乙烯）污染物为研究对象，研究纳米气泡强化纳米铁吸附降解污染物的过程机制和反应动力学，并考察不同环境影响因子。研究结果将为环境纳米技术的应用推广提供一定的理论和数据基础。

本研究通过变温和微波的方法，在活性炭表面和HOPG表面分别制备一定量的氧纳米气泡，并研发了一套新的方法和装置，能够测定负载到固体颗粒表面上氧纳米气泡的总量，目前国内外尚缺乏用于表征颗粒材料上纳米气泡负载量的方法，该方法是现有纳米气泡表征手段的有效补充。同时研究了纳米气泡在促进污染物降解方面的关键作用和影响因素，研究表明纳米气泡能够有效促进四环素类污染物的光催化降解效率，主要是由于纳米气泡具有大的比表面积，同时气泡破裂过程中还可以产生活性自由基。