Role of nanominerals on photochemical derived atmospheric NH3 and N2O

重要的证据表明，全球氮循环是不平衡的。农业的集约化和化石燃料燃烧排放的增加是造成这种不平衡的主要原因，因为在上个世纪，这两种人为活动使活性氮的排放量增加了三倍。此外，这些有害的环境污染物是形成某些气溶胶的原因，这些气溶胶对自然生态系统和人类健康都有负面影响。解决这种不平衡的工程方案的主要挑战在于量化和确定大气和土壤圈中所有的全球氮通量。这需要对自然和人为源和汇进行高分辨率测量。这项研究将旨在量化由于土壤纳米矿物和阳光之间的纳米级相互作用而产生的自然氮基大气排放的速率。目前，人为源通常比自然或半自然源的排放更准确。因此，进一步努力确定哪些纳米尺度现象有助于土壤中氮的形成和氮基排放，对于提高我们对全球氮循环的理解至关重要。这项工作还将支持本科教育，作为佐治亚理工学院“食物-能源-水倡议”顶点项目的基础，该项目通过“服务-学习-持续”项目得以实现。这个顶级项目将吸引来自包括工程和社会科学在内的一系列学科的本科高年级学生。此外，这项工作旨在通过与亚特兰大广泛倡议科学-艺术-奇迹的合作，吸引非科学界。通过这个项目，研究人员将与艺术家合作，将重要的科学发现转化为艺术作品，并在亚特兰大科学节上展出。该项目的主要研究目的是了解土壤和沙子中富含光催化土的纳米矿物如何促进活性氮的排放。具体来说，该项目将调查矿物、土壤和大气特性在增加纳米矿物的活性以生产氨和氧化亚氮方面所起的作用。通过光（电）催化测试，探索常见纳米矿物的纳米级结构-性能关系，以了解矿物粒度和表面纳米结构对催化活性的影响。深入的第一性原理计算和大气测试也将阐明纳米级化学机制和物理现象促进阳光驱动的土壤和沙子的活性氮生产和排放。这一基本认识将有助于深入了解陆地纳米矿物在调节自然氮循环中的作用，为陆地和大气环境中更准确的养分通量模型奠定基础。该项目将寻求对土壤和农业在大气污染中所起的作用建立一个全面的看法。这项工作的影响将通过外联和教育努力得到加强。研究结果将通过一个可公开访问的网站和YouTube视频进行突出展示，这些视频展示了主要发现，并建议用家庭用品进行简单的实验。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Significant evidence suggests that the global nitrogen cycle is not balanced. The intensification of agriculture and rising emissions from the burning of fossil fuels are largely responsible for this imbalance, as both of these anthropogenic activities have enhanced reactive nitrogen emissions by a factor of three over the last century. Furthermore, these harmful environmental pollutants are responsible for the formation of certain aerosols, which have negative implications for both natural ecosystems and human health. A chief challenge in engineering solutions to this imbalance lies in quantifying and identifying all global nitrogen fluxes in the atmosphere and pedosphere. This requires high-resolution measurements of both natural and anthropogenic sources and sinks. This research will aim to quantify the rate of natural nitrogen-based atmospheric emissions that arise due to nanoscale interactions between soil nanominerals and sunlight. Currently, anthropogenic sources are generally more accurately mapped than emissions from natural or semi-natural sources. Therefore, further efforts to identify which nanoscale phenomena aid the formation and nitrogen-based emission in soils is important to advance our understanding of the global nitrogen cycle. The work will also support undergraduate education, serving as the basis of a capstone project through Georgia Tech's Food-Energy-Water initiatives, which is enabled through the Serve-Learn-Sustain program. This capstone project will engage undergraduate seniors from a range of academic disciplines including engineering and social sciences. In addition, this work seeks to engage the non-scientific community through a collaboration with the Atlanta wide initiative Science-Art-Wonder. Through this program, researchers will collaborate with artist to transform key scientific findings into art pieces that will be displayed at the Atlanta science festival. The main research objective of this project is to understand how photocatalytic earth-abundant nanominerals in soils and sands contribute to reactive nitrogen emissions. Specifically, the PI will investigate the role mineral, soil and atmospheric properties play in increasing the activity of nanominerals for ammonia and nitrous oxide production. The nanoscale structure-property relationships of common nanominerals will be probed through photo(electro)catalytic testing to discern the impact mineral size and surface nanostructure have on catalytic activity. In depth first-principles calculations and atmospheric testing will also elucidate which nanoscale chemical mechanisms and physical phenomena promote sunlight driven reactive nitrogen production and emission from soils and sands. This fundamental understanding will provide insight into the role terrestrial nanominerals play in mediating the natural nitrogen cycle, providing a foundation for more accurate models of nutrient fluxes in terrestrial and atmospheric settings. The project will seek to establish a holistic view of the role soils and agriculture play on atmospheric pollution. The impact of the work will be enhanced by outreach and educational efforts. The findings will be highlighted through a publicly accessible website and YouTube videos that demonstrate key findings and suggest simple experiments that can be performed with household items.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.