RUI: Engineering Organosilica Materials that Rapidly and Reversible Swell for Water Remediation

对净水技术的需求很大，特别是在淡水供应日益紧张的情况下，需求持续增加。工业活动、现代农业实践和各种化学品的广泛使用导致了有机污染物对水的污染。有机溶剂、杀虫剂和其他新出现的污染物已经渗入流域，使这些水不适合人类使用，直到污染物种被清除。最近，我们发现了一类新的化学惰性硅基材料，在有机液体存在下，它可以膨胀8倍于其干体积。这种材料的膨胀速度很快，能量很高，产生的力超过100N/g。可膨胀有机改性二氧化硅(SOMS)在水中不膨胀，但具有从水或空气中吸附大量溶解有机物种的能力。初步工作表明，SOMS能有效地从水中去除多种有机物，包括极性物质，如醇和甲基叔丁基醚，以及非极性物质，如甲苯和四氯乙烯。当被吸收的物质通过加热材料蒸发时，膨胀过程是完全可逆的。出于这些原因，SOMS基吸附剂似乎是被有机物种污染的水的环境修复的理想选择。拟议工作的目标是：1.对这些新型二氧化硅材料的吸收有一个基本的了解。2.制造以去除水中的卤代有机物和杀虫剂为目标的复合材料。3.与当地一家工程公司合作开发和测试部署机制。基于其不同寻常的特性，SOMS可能代表了一种全新的吸收材料类别。有机物种的侵入导致基质的膨胀，而基质在干燥状态下处于拉伸状态。提出了一项实验工作，试图创建一个物理和热力学模型来解释吸收过程。这将通过光谱、量热法和平衡吸收测量的组合来完成。这些结果将与从经典Flory-Huggins模型扩展而来的理论框架进行比较，并研究由静电力拉伸的矩阵组成的聚电解质可膨胀聚合物体系。除了为动画材料的吸收奠定理论基础外，基于SOMS的吸附剂还将被设计用于去除/降解各种类型的污染物，包括杀虫剂、氯化溶剂，特别是三氯乙烯(TCE)和含氟化合物。将零价铁纳米颗粒(纳米ZVI)结合到SOMS中的复合材料将被创造出来，以吸收TCE，然后通过隔离在材料中的铁将其还原为氯离子和乙烯来将其转化。这种复合材料将以泥浆形式制备，注入地下含水层。土壤注入方法和试点试验将由位于邻近地区的一家环境工程公司(Frontz)合作进行，该公司专门从事ZVI和其他地下处理方法的部署，以修复含水层。Frontz拥有移动声波钻机和GeoProbe注入设备。化学修饰材料将在另一项研究中合成从水中去除含氟化合物。这项工作的最初目标化合物是全氟辛酸盐，事实证明，它很难通过其他措施去除，并将作为一个模型系统，用于研究基于SOMS的材料是否可以通过分子工程来选择性地吸收特定类别的物质。所有工作将在一所文科学院完成，该学院将为10-15名化学学生提供应用环境工程方面的研究经验，这对该机构来说是一个新领域。这些学生将担任SEER计划的导师，该计划是在伍斯特开发的，旨在招募大学前的少数族裔进入科学界。本科生研究人员还将带领一组初中女孩进行环境实验，作为B-WISER夏令营的一部分。

0930371EdmistonThere is significant need for technologies to clean water, especially as demand continues to increase while fresh water supplies become increasingly strained. Industrial activity, modern agricultural practices, and widespread use of various chemicals has led to contamination of water by organic pollutants. Organic solvents, pesticides, and other emerging contaminants have infiltrated watersheds making such water unfit for use by humans until the contaminating species are removed. Recently, we discovered a new class of chemically inert silica-based materials that swell 8 times their dry volume in the presence of organic liquids. The expansion of the material is rapid and highly energetic resulting in forces that exceed 100N/g. Swellable organically modified silica (SOMS) does not swell in water, but has the capability of adsorbing large amounts of dissolved organic species from water or air. Preliminary work has shown that SOMS is effective at removing a wide range of organics from water including polar species such as alcohols and methyl tert-butyl ether to non-polar species such and toluene and perchloroethylene. The swelling process is completely reversible when absorbed species are evaporated by heating the material. For these reasons SOMS-based sorbents appear to be ideal for environmental remediation of water contaminated by organic species. The goals of the proposed work are to: 1. Develop a fundamental understanding of absorption by these novel silica materials. 2. Create composite materials that target the removal of halogenated organics and pesticides from water. 3. Develop and test deployment mechanisms in collaboration with a local engineering firm. Based on its unusual properties, SOMS may represent a whole new class of absorbent materials. Incursion of organic species leads to the expansion of the matrix which is under tension in the dry state. Experimental work is proposed that will seek to create a physical and thermodynamic model to explain the absorption process. This will be done through a combination of spectroscopic, calorimetric, and equilibrium absorption measurements. These results will be compared to a theoretical framework developed by extension from the classical Flory-Huggins model and work on polyelectrolyte swellable polymers systems consisting of matrixes tensioned by electrostatic forces. Beyond laying a theoretical groundwork for absorption by animated materials, SOMS-based sorbents will be designed to remove/degrade various types of contaminants including: pesticides; chlorinated solvents, in particular trichloroethylene (TCE) and fluorinated compounds. Composite materials where nanoparticles of zerovalent iron (nanoZVI) are incorporated into SOMS will be created to absorb TCE and subsequently covert it through reduction to chloride ion and ethylene by iron sequestered within the material. The composite materials will be prepared in slurries for injection into underground aquifers. Soil injection methods and pilot experiments will be conducted in collaboration by an environmental engineering firm (Frontz) located in the immediate area that specializes in the deployment of ZVI and other sub-surface treatment methodologies for aquifer remediation. Frontz owns mobile sonic drilling rigs and GeoProbe injection equipment. Chemically modified materials will be synthesized remove fluorinated compounds from water in a separate line of investigation. The initial target compound for this work is perfluorooctanoate which has proven difficult to remove by other measures and will serve as a model system for investigating whether SOMS-based materials can be molecularly engineered to selectively absorb a particular class of substances. All the work will be accomplished at a liberal arts college which will provide 10-15 chemistry students with research experiences in applied environmental engineering, an area that would be new to the institution. These students would serve as mentors for the SEER program which was developed at Wooster to recruit pre-college minorities into the sciences. Undergraduate researchers would also lead groups of junior high girls in environmental experiments as part of the B-WISER summer science camp.