Integrated Study of Nanopowder Synthesis and Pollutant Control using Electrically-Assisted Combustion

这项工作的目标是对受外电场影响的燃烧系统中颗粒形成、生长和聚集机制的基本理解，并利用这种理解来确定工艺条件，从而实现非团聚纳米粉末的高速沉积和污染物颗粒排放的控制。最初研究的陶瓷纳米粉末是二氧化硅（SiO2），二氧化钛（TiO2），氧化铝（Al2O3）和氧化锆（ZrO2），使用高挥发性前驱体。所调查的污染物颗粒是煤烟和含有铅（Pb）和铬（Cr）等有毒金属的颗粒。综合研究项目涉及应用电场对火焰中固体颗粒形成的影响，并同时解决材料合成和环境工程中的问题。在空气动力学简单的流场，即平焰停滞点（预混）和平焰逆流（非预混）中进行实验，表征电场和其他可控工艺参数（包括压力）对化学成分、初级粒度、结晶度和团聚度的影响。使用多种前体生产掺杂、包覆或混合纳米晶体纳米颗粒的研究。在电场中，薄膜沉积的特性从组成、形貌、沉积模式和烧结等方面进行了研究。先进的激光诊断、电子显微镜和x射线衍射被用来模拟和分析火焰结构（由于过程输入）对粒子演化的影响。结合详细的气相化学动力学和输运（包括电场效应）的计算模型与粒子形成、生长和聚集的模型一起开发。在已经证明的火焰合成纳米粉末的工艺中，应用电场的方法在精确控制初级粒度、结晶度和聚集体尺寸方面是最有前途的方法之一。同样的方法也可用于控制用于发电和焚烧的燃烧系统的微粒排放。研究和实验设施被纳入纳米材料科学与工程的新课程，作为几个系之间的联合项目，并纳入高级实验方法的研究生课程。作为罗格斯大学数学、科学和工程女性道格拉斯项目的一部分，通过支持本科生研究，增加了未被充分代表的少数民族和女性在工程领域的参与。通过与工业、州和纳米材料研究中心合作，促进了对学生（高中、本科和研究生）的高技术劳动力的培训。

The objective of this work is fundamental understanding of the mechanisms of particle formation, growth, and aggregation in combustion systems subjected to external electric fields and utilization of that understanding to define process conditions that enable both high-rate deposition of non-agglomerated nanopowders and control of pollutant particulate emissions. The ceramic nanopowders investigated Initially are silica (SiO2), titania (TiO2), alumina (Al2O3) and zirconia (ZrO2) using highly volatile precursors. The pollutant particulates investigated are soot and particulates containing toxic metals such as lead (Pb) and chromium (Cr). The consolidated research program deals with the effects of applying electric fields on formation of solid particles in flames and addresses concurrently issues in both materials synthesis and environmental engineering. Experiments are conducted in aerodynamically simple flow fields, i.e. flat-flame stagnation-point (premixed) and flat-flame counterflow (non-premixed), to characterize the effects of electric field and of other controllable process parameters (including pressure) on chemical composition, primary particle size, crystallinity, and degree of agglomeration. The use of multiple precursors to produce doped, coated, or mixed nanocyrstalline nanoparticlesis investigated. The characteristics of film deposition in an electric field are examined with respect to composition, morphology, deposition patterns, and sintering. Advanced laser diagnostics, electron microscopy, and X-ray diffraction are utilized to model and analyze the effects of flame structure (due to process inputs) on particle evolution. A computational model incorporating detailed gas-phase chemical kinetics and transport (including electric field effects) is developed along with models for particle formation, growth, and aggregation. Broader impact Among the processes that have been demonstrated for flame synthesis of nanopowders, the approach of applying electric fields is one of the most promising in terms of precise control of primary particle size, crystallinity, and aggregate size. The same methodology can be used for the control of particulate emissions from combustion systems used for power generation and incineration. The research and experimental facility are incorporated into the new curriculum onnanomaterials science and engineering being offered as a joint program between several departments and into the graduate curriculum on advanced experimental methods. The involvement of underrepresented minorities and women in engineering is increased by supporting undergraduate research as part of the Douglass Project for Rutgers Women in Math,Science, and Engineering. The training of students (at high school, undergraduate, and graduate levels) for the high-technology workforce is promoted by partnering with industry, state, and the Center for Nanomaterials Research..