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

项目概述：研究员：通过硅藻的电化学还原和废水修复和生物燃料工业的可持续纳米硅生产espi: Steven N. Girard，威斯康星大学麦迪逊分校丰富的无毒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，必须大量经济和可持续地生产。目前的硅生产依赖于消耗能源和材料的碳热还原过程，其中碳和沙子（二氧化硅）在非常高的温度下反应产生冶金硅和二氧化碳。冶金硅随后在多个能源和材料消耗步骤中溶解，精炼和再结晶，以产生用于可再生能源应用的纳米硅。为了将纳米硅用于可再生能源，必须从可持续性的角度重新设计硅的大规模生产。我建议开发一种全新的纳米硅到纳米硅的直接电化学转化过程，这将是能源和材料效率高的，因此价格低廉，可持续发展。通过与工业合作伙伴algaexperts的合作，我们还将分析该方法的可扩展性和可行性，通过将这些过程中的纳米硅藻（二氧化硅）回收利用，整合到现有的废水修复和藻类生物燃料工业中。知识价值。通过电化学还原硅藻的纳米结构硅晶块，开发了一种可持续和直接生产纳米硅的新工艺。天然硅藻（单细胞藻类）的纳米结构二氧化硅微壳既便宜又容易从开采的硅藻土沉积物或硅藻培养物中获得。在威斯康星大学麦迪逊分校化学系宋瑾教授的指导下，该研究计划寻求在新型共晶盐电解质中开发纳米二氧化硅的电化学还原，这将使在非常低的温度下单步生产纳米硅，消耗更少的能量。如果在转化为硅后，初始纳米形态能够保持不变，那么这一工艺将是迄今为止最具可持续性的纳米硅生产方法。更广泛的影响。拟议的研究将立即对各种工业应用有用，并暴露了see的新化学技术。我们进一步建议从工业规模的藻类培养中收获特定的硅藻属，用于废水废水的生物修复和生物燃料脂类的生产。获得特定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、algaexperts LLC总裁Jun Yoshitani合作，分析这些方法在中西部水处理设施整合的可行性。此外，这项合作研究将包括对废水流出养分的化学分析，工业规模培养中特定属的选择性，以及相关成本的分析。see研究员将更好地理解与实施大规模可持续性技术相关的工业考虑。教育宣传。与威斯康星大学麦迪逊分校尼尔森环境研究所Greg Nemet教授和威斯康星大学麦迪逊分校REU项目主任Andrew Greenberg博士合作，将设计和实施一个高度跨学科的夏季实习，重点关注公共政策和可持续性科学。在初级研究中获得的经验教训将被整合到该大学的暑期实习中。与格林伯格博士合作，少数族裔本科生研究人员将由see研究员指导与拟议研究相关的夏季研究项目。see研究员将获得可持续发展政策、教学、课程设计、教学与研究整合以及本科生指导方面的经验。

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.