SEES Fellows: Sustainable Nanosilicon Production through the Electrochemical Reduction of Diatoms and Integration into Wastewater Remediation and Biofuel Industries

SEES 研究员：通过硅藻电化学还原实现可持续纳米硅生产并融入废水修复和生物燃料行业

• 批准号: 1313968
• 负责人: Steven Girard
• 金额: $ 14.65万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1313968&HistoricalAwards=false
• 关键词: SEES; Fellows; Sustainable; Nanosilicon; Production

Project SummarySEES Fellows: Sustainable Nanosilicon Production through the Electrochemical Reductionof Diatoms and Integration into Wastewater Remediation and Biofuel IndustriesPI: Steven N. Girard, University of Wisconsin MadisonNanostructures of abundant and non-toxic silicon can serve a significant role in various renewableenergy technologies, including solar cells, Li-ion batteries, and thermoelectric materials. To realizethe potential of nanosilicon for renewable energy applications, mass quantities must be economicallyand sustainably produced. Current silicon production relies on an energy- and material- consumingcarbothermal reduction process, in which the reaction between carbon and sand (silica) at very hightemperatures yields metallurgical silicon and carbon dioxide. Metallurgical silicon is subsequentlydissolved, refined, and recrystallized in multiple energy- and material-consuming steps to generatenanosilicon for renewable energy applications. For nanosilicon to be used for renewable energy, thelarge scale production of silicon must be redesigned from a sustainability perspective. I propose todevelop an altogether new process of direct electrochemical conversion of nanosilica-to-nanosiliconthat will be energy and material efficient, and therefore inexpensive and sustainable. In collaborationwith industrial partner AlgaXperts, we will also analyze the scalability and feasibility of thisapproach through the integration into existing wastewater remediation and algae-for-biofuelindustries by essentially recycling the nanostructured diatoms (silica) from these processes.Intellectual Merit.A novel process of sustainable and direct nanosilicon production through theelectrochemical reduction of nanostructured silica frustules of diatoms will be developed. Thenaturally nanostructured silica microshells of diatoms (unicellular algae) are inexpensive and easilyobtained either from mined diatomaceous earth deposits or from diatom algal cultures. Under hostmentor Prof. Song Jin, Department of Chemistry at UW-Madison, the proposed research seeks todevelop electrochemical reduction of nanosilica within novel eutectic salt electrolytes, which willenable single-step nanosilicon production at very low temperatures, consuming considerably lessenergy. If the starting nanomorphologies can be retained following conversion to silicon, thisprocess will represent the most sustainable means of nanosilicon production to date.Broader Impact.The proposed research will be immediately useful for a variety of industrialapplications and expose the SEES fellow new chemical techniques. We further propose harvestingspecific diatom genera from industrial-scale algal cultures used for the bioremediation of wastewatereffluent and production of lipids for biofuels. Obtaining specific diatom genera allow control overthe types of nanostructures obtained. In collaboration with partner mentor Jun Yoshitani, Presidentof AlgaXperts LLC, we will analyze the feasibility of the integration of these approaches at aMidwestern water treatment facility. Furthermore, this collaborative research will involve chemicalanalysis of the wastewater effluent nutrients, selectivity of specific genera in industrial-scale cultures,and analysis of the associated costs. The SEES fellow will gain a better understanding of theindustrial considerations connected to implementing large-scale sustainability technologies.Educational Outreach.In collaboration with Prof. Greg Nemet, Nelson Institute of EnvironmentalStudies at UW-Madison, and Dr. Andrew Greenberg, Director of REU programs at UW-Madison, ahighly interdisciplinary summer practicum focusing on public policy and sustainability science willbe designed and implemented. Lessons learned in the primary research will be integrated into theREU summer practicum. In collaboration with Dr. Greenberg, underrepresented minorityundergraduate researchers will be mentored by the SEES fellow in summer research projects relatedto the proposed research. The SEES fellow will gain experience in sustainability policy, teaching,course design, integration of teaching and research, and undergraduate mentoring.

项目摘要SEES成员：通过电化学还原硅藻并整合到废水修复和生物燃料工业中的可持续纳米硅生产PI：威斯康星大学麦迪逊分校的Steven N.Girard丰富和无毒的硅纳米结构可以在各种可再生能源技术中发挥重要作用，包括太阳能电池、锂离子电池和热电材料。为了实现纳米硅在可再生能源应用中的潜力，必须以经济和可持续的方式大量生产。目前的硅生产依赖于耗能和耗材的碳热还原工艺，在该工艺中，碳和沙子(二氧化硅)在非常高的温度下反应产生冶金硅和二氧化碳。冶金硅随后通过多个耗能和耗材的步骤进行溶解、精炼和再结晶，以生产用于可再生能源应用的非金属硅。为了将纳米硅用于可再生能源，必须从可持续发展的角度重新设计大规模的硅生产。我建议开发一种将纳米二氧化硅直接电化学转化为纳米硅的全新工艺，这种工艺将节能、节材，因此成本低廉且可持续。我们还将与工业合作伙伴AlgaXperts合作，通过将这些过程中的纳米结构硅藻(二氧化硅)回收到现有的废水修复和藻类生物燃料行业中，分析这种方法的可扩展性和可行性。智能价值。将开发一种通过电化学还原硅藻的纳米结构二氧化硅颗粒来可持续和直接生产纳米硅的新工艺。硅藻(单细胞藻类)的天然纳米结构二氧化硅微壳价格低廉，而且很容易从开采的硅藻土沉积物或硅藻培养物中获得。在华盛顿大学麦迪逊分校化学系主任宋进教授的指导下，这项拟议的研究旨在开发新型共晶盐电解液中纳米二氧化硅的电化学还原，这将使纳米硅能够在极低的温度下一步生产纳米硅，消耗的能源大大减少。如果在转化为硅后仍能保持初始的纳米形态，这一过程将是迄今为止最可持续的纳米硅生产方法。所提出的研究将立即对各种工业应用有用，并展示其他新的化学技术。我们还建议从工业规模的藻类养殖中收获特定的硅藻属，用于废水的生物修复和生产生物燃料的脂类。获得特定的硅藻属可以控制所获得的纳米结构的类型。我们将与合作伙伴导师、阿尔加Xperts有限责任公司总裁吉谷俊合作，分析中西部一家水处理设施整合这些方法的可行性。此外，这项合作研究将涉及废水流出物营养成分的化学分析、工业规模培养中特定属的选择性以及相关成本的分析。SEES研究员将更好地了解与实施大规模可持续发展技术相关的行业考虑因素。教育领域。将与威斯康星大学麦迪逊分校纳尔逊环境研究所的格雷格·内梅特教授和威斯康星大学麦迪逊分校的REU项目主任安德鲁·格林伯格博士合作，设计和实施一个高度跨学科的暑期实习，重点是公共政策和可持续发展科学。在初步研究中学到的经验教训将被纳入REU暑期实习。在与格林伯格博士的合作下，在与拟议研究相关的夏季研究项目中，代表不足的少数本科生研究人员将得到SEE研究员的指导。Sees研究员将在可持续发展政策、教学、课程设计、教学和研究一体化以及本科生指导方面获得经验。

项目成果

Twisting phonons in complex crystals with quasi-one-dimensional substructures

• DOI: 10.1038/ncomms7723
• 发表时间: 2015-04-01
• 期刊: NATURE COMMUNICATIONS
• 影响因子: 16.6
• 作者: Chen, Xi;Weathers, Annie;Shi, Li
• 通讯作者: Shi, Li

Thermoelectric Properties of Undoped High Purity Higher Manganese Silicides Grown by Chemical Vapor Transport

• DOI: 10.1021/cm5023823
• 发表时间: 2014-09-09
• 期刊: CHEMISTRY OF MATERIALS
• 影响因子: 8.6
• 作者: Girard, Steven N.;Chen, Xi;Jin, Song
• 通讯作者: Jin, Song

Approaching the Minimum Thermal Conductivity in Rhenium-Substituted Higher Manganese Silicides

• DOI: 10.1002/aenm.201400452
• 发表时间: 2014-10-07
• 期刊: ADVANCED ENERGY MATERIALS
• 影响因子: 27.8
• 作者: Chen, Xi;Girard, Steven N.;Shi, Li
• 通讯作者: Shi, Li