基于耦合效应的纳米复合材料与典型污染物相互作用研究

It is a hard task to detect and capture the elemental mercury in flue gas or atmosphere. Mercury is mainly present in three chemical forms or species in flue gas or atmosphere including elemental mercury (Hg0), oxidized mercury (Hg2+) and particulate-bound mercury (Hgp). The essence of mercury control is to transform elemental mercury (Hg0) into soluble (Hg2+) or bound forms (Hgp) in various phases. The key point for mercury control is to discover or synthsize new adsorbents for various mercury species with high capacity and good selectivity. Nanoselenium and nanosilver were reported to have huge adsorption capacity for mercury. Based on this, the coupling effects between different nanomaterials can also greatly enhanced the adsorption capacity of nanocomposites. The recognization of nano effects and coupling effects will be very helpful for us to develop some new methods and techniques for mercury control. So, it is very significant to synthesize new nanomaterials or nanocomposites and to study the interaction process between the nanocomposites and the various mercury species. . In this proposal, nanoselenium, nanosilver, nanopalladium will be synthesized onto the surface of magnetic carbon nanomaterials including carbon nanotubes and graphene. Based on the synthesis of the nanocomposites, the coupling effects and nano effects on the adsorption of mercury will be studied. The adsorption process of different mercury species (Hg0 and Hg2+) in different phases on the surface of the composites will also be investigated. This study will be very significant and very helpful for us to discover new mechanism and novel methods for mercury control and detection.

烟气和大气中气态元素汞污染控制与检测是目前环境科学与工程领域的难点，对其进行控制的本质是将易逃逸的气态元素汞形态转化为不易逃逸或被锁定的汞形态，研究的关键是发展吸附容量大、特异性强、可回收、能再生的新型吸附材料。纳米硒和纳米银对汞表现出强大特异性吸附的纳米效应刚刚被认识，而纳米复合材料的耦合效应又可进一步增强其本征性能。因此，制备基于纳米耦合效应的汞亲和元素纳米复合材料，并深入研究不同形态汞在其表面的作用过程，对发现新的汞污染控制原理和方法具有非常重要的理论意义。本课题拟针对纳米硒、纳米银和纳米钯为分散对象，以碳纳米管和石墨烯为分散骨架，制备系列磁性修饰多功能纳米复合材料，深入研究不同物相、不同形态汞（Hg0和Hg2+）在材料表面的多相作用过程，探讨纳米耦合效应下复合材料对不同形态汞的吸附机制，为发展烟气、大气、水中汞污染控制和样品前处理新方法、揭示新机理提供参考和依据

汞污染控制是目前环境科学与工程领域研究的重点，开发吸附容量大、选择性好、能回收、可再生的吸附材料对不同形态汞的去除和检测均具有重要意义。基于汞亲和元素的纳米材料对汞的吸附性能优越，以碳纳米材料为骨架，制备其复合纳米材料，可以将贵金属纳米颗粒或其他高活性纳米粒子分散在骨架上，既可以防止纳米颗粒团聚又可以增大材料作用面积、降低成本，且在制备过程中还可以将材料磁性修饰，进一步制得磁性复合材料，便于回收利用和再生。课题紧紧围绕上述研究内容和目标，制备了银、钯、硒负载的系列纳米复合材料，通过水热法进一步制备了基于铁氧化物的磁性纳米复合材料，采用SEM、TEM、XRD、EDS和VSM一系列现代仪器表征手段对所制备的纳米复合材料的形貌、结构、组成以及磁性进行了表征；自行设计了烟气模拟装置、固定床汞脱除实验平台和在线联用测汞系统，满足了吸附材料对气态元素汞的吸附性能评价和相互作用研究需求；采用固定床实验平台，详细考察了银、钯、硒纳米修饰碳纳米复合材料对气态元素汞（Hg0）的吸附过程和特征，考察了不同气体组分对吸附性能的影响；通过固定床吸附实验，详细研究了磁性纳米复合材料对气态元素汞的吸附性能，考察了不同气体组分对吸附性能的影响；采用静态吸附实验研究了磁性纳米复合材料对水体中汞离子（Hg2+）吸附，并对吸附动力学和热力学进行了研究，初步探讨了吸附机理；采用热解实验和洗脱方法对材料的再生能力进行了评价，优选出了可行的回收再生方法，为材料的实际应用创造了条件。研究较好地执行了项目原定研究计划，取得了预期的研究成果。