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

0930371 Edmiston对清洁水技术的需求非常大，特别是在需求持续增加而淡水供应日益紧张的情况下。工业活动、现代农业实践和各种化学品的广泛使用导致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透到流域，使得这些水不适合人类使用，直到污染物种被去除。最近，我们发现了一类新的化学惰性硅基材料，在有机液体的存在下膨胀8倍于其干体积。材料的膨胀是快速的，并且是高能量的，导致超过100 N/g的力。可溶胀的有机改性二氧化硅（SOMS）在水中不溶胀，但具有从水或空气中吸附大量溶解的有机物质的能力。初步研究表明，SOMS可有效地从水中去除各种有机物，包括极性物质如醇和甲基叔丁基醚到非极性物质如甲苯和全氯乙烯。当吸收的物质通过加热材料蒸发时，溶胀过程是完全可逆的。由于这些原因，SOMS为基础的吸附剂似乎是理想的环境修复的水污染的有机物种。本文的工作目标是：1.发展对这些新型二氧化硅材料吸收的基本理解。2.创建复合材料，目标是从水中去除卤代有机物和农药。3.与当地工程公司合作开发和测试部署机制。基于其不寻常的特性，SOMS可能代表了一类全新的吸收材料。有机物质的侵入导致在干燥状态下处于张力下的基质的膨胀。实验工作提出，将寻求建立一个物理和热力学模型来解释吸收过程。这将通过光谱、量热和平衡吸收测量的组合来完成。这些结果将进行比较，从经典的Flory-Huggins模型和工作的可膨胀的聚合物系统组成的矩阵张紧的静电力的扩展开发的理论框架。除了为活性材料的吸收奠定理论基础外，SOMS吸附剂还将被设计用于去除/降解各种类型的污染物，包括：农药;氯化溶剂，特别是三氯乙烯（TCE）和氟化化合物。将零价铁纳米颗粒（nanoZVI）掺入SOMS的复合材料将被创建以吸收TCE，随后通过材料内螯合的铁还原为氯离子和乙烯将其转化。复合材料将制成泥浆，注入地下含水层。土壤注入方法和试点实验将由一家环境工程公司（Frontz）合作进行，该公司位于邻近地区，专门从事零排放指数和其他地下处理方法的部署，用于含水层补救。Frontz拥有移动的声波钻机和GeoProbe注入设备。化学改性材料将在另一项研究中合成，以去除水中的含氟化合物。这项工作的初始目标化合物是全氟辛酸酯，它已被证明难以通过其他措施去除，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选择性地吸收特定类别的物质。所有的工作将在一所文理学院完成，该学院将为10-15名化学专业的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的领域。这些学生将担任导师的SEER计划，这是在伍斯特开发，以招募大学前的少数民族进入科学。作为B-WISER暑期科学夏令营的一部分，本科研究人员还将带领初中女生参加环境实验。

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.