Development of Anti-biofouling Nanocomposite Polypropylene Fibers for Membrane Feed Spacers

CBET-0754387E耐生物污染膜间隔隔膜用纳米复合丙纶的开发膜技术为满足饮用水生产日益严格的法规要求提供了极大的希望。虽然其他技术可以实现类似的处理目标，但膜提供了显著的优势。纳滤(NF)和反渗透(RO)膜使得替代水回收(即微咸水和海水)和废水再利用成为可能的解决方案，以解决日益严重的全球传统水源短缺的问题。在处理传统水源时实施纳滤和反渗透工艺可以提供稳定的去除水平，从而消除了再生离子交换树脂或颗粒活性碳的需要。此外，反渗透可透过淡化海水和咸水，满足未来的食水需求。虽然纳滤膜和反渗透膜一般不用于消毒，但它们为病毒和细菌的去除提供了额外的屏障，这对于间接饮用和废水回用是必不可少的。然而，对膜技术未来的乐观看法必须缓和下来，因为认识到仍然需要解决的技术和成本问题。在这些问题中，被拒绝的化学品和微生物对膜的污染继续需要相当多的关注。该项目的重点是微生物污染，或称生物污染，即微生物聚集在膜表面和进料间隔上，出现在包膜之间(即螺旋缠绕元件，其中膜折叠在连接到中心管的聚丙烯间隔上)。在防止生物污染方面，大部分研究和开发都集中在给水的预处理、改进的清洗液、清洗程序和耐污染膜上。本项目的目标是开发负载铜或银离子的抗生物污垢纳米复合聚丙烯(PP)纤维。然后，这些PP纤维将被用来制造RO螺旋缠绕元件的进料垫片。铜离子和银离子是有效的消毒剂，通常是通过电解或作为金属盐添加到水中来对水进行消毒。使用防生物污垢进料间隔物的优势将是降低与化学品添加/储存相关的成本。智能优点：这里提出的新奇之处是将金属亲和配体共价结合到可以带电的铜或银离子的PP纤维上，以允许金属缓慢释放到膜系统的给水中，以控制生物污染。选择固定化金属亲和层析(IMAC)体系是因为该体系易于功能化，并且能够通过修饰初始金属亲和配体来控制铜/银的结合程度。这里提出的假设是，PP纤维可以与铜/银特异的金属亲和配体形成纳米结构，从而形成抗生物污染的膜馈入间隔物。为了验证假设，该项目分为三个目标：1.目标A：对纳米复合PP纤维进行功能化处理。2.目的B：测试纳米复合PP纤维的生物污垢性能。3.目的C：测定纳米复合纤维对膜的影响。更广泛的影响：当施加驱动力时，膜能够根据物种的物理和化学性质来分离物种，并且它们能够过滤以去除胶体、细胞和分子。与膜的使用相关的主要问题是污染。膜污染通过通量损失、压力增加和清洗频率对膜的性能和成本产生不利影响。开发一种低污染的膜过程是圣杯？膜研究的最新进展。拟议项目的成果将通过对研究生和本科生的培训、同行评议的出版物和会议发言以及对代表不足的年轻移徙学生进行有关饮用水问题和处理的教育来传播。

CBET-0754387EscobarDevelopment of Anti-biofouling Nanocomposite Polypropylene Fibers for Membrane Feed Spacers Membrane technologies offer great promise to meet increasingly stringent regulatory requirements for potable water production. While other technologies can achieve similar treatment objectives, membranes offer notable advantages. Nanofiltration (NF) and reverse osmosis (RO) membranes have made alternative water reclamation (i.e., brackish water and seawater) and wastewater reuse possible solutions to address the growing global scarcity of traditional water sources. Implementation of NF and RO processes in treating traditional water sources can provide a steady-state level of removal that eliminates the need for regeneration of ion exchange resins or granular activated carbon. Moreover, RO can help meet future potable water demands through desalination of seawater and brackish waters. Although NF and RO membranes are generally not intended for disinfection, they provide an additional barrier for virus and bacteria removal, which is essential for indirect potable, wastewater reuse. An optimistic view for the future of membrane technology must be tempered, however, by recognition of the technical and cost issues that remain to be addressed. Of these issues, the fouling of membranes by chemicals and microbes that are rejected continues to demand considerable attention. The focus of this project is microbial fouling, or biofouling, which is the accumulation of microorganisms onto the membrane surface and on the feed spacer as present between the envelopes (i.e. spiral wound elements, in which the membrane is folded over a polypropylene spacer attached to a center tube). Most of the research and development in the area of biofouling prevention has focused on pretreatment of the feed water, improved cleaning solutions, cleaning procedures, and fouling resistant membranes. The goal of this project is to develop anti-biofouling nanocomposite polypropylene (PP) fibers loaded with copper or silver ions. These PP fibers will then be used to make feed spacers for RO spiral wound elements. Copper and silver ions are effective disinfectants and, conventionally, have been added to the water electrolytically or as metal salts to disinfect water. The advantage of using anti-biofouling feed spacers would be to decrease costs associated with chemical additions/storage. Intellectual Merit: The novelty proposed here is to covalently bind metal affinity ligands to PP fibers that can be charged with copper or silver ions to allow for slow release of metals into the feedwater in membrane systems for biofouling control. The immobilized metal affinity chromatograph (IMAC) system was chosen because of ease of functionalization and ability to control the degree of copper/silver binding through modification of the initial metal affinity ligand. The hypothesis proposed here is that PP fibers can be nanostructured with metal affinity ligands specific to copper/silver to lead to biofouling resistant membrane feed spacers. To test the hypothesis, the project is divided into three objectives: 1. Objective A: Functionalize the nanocomposite PP fibers. 2. Objective B: Test the biofouling properties of the nanocomposite PP fibers. 3. Objective C: Determine the effects of the nanocomposite fibers on the membrane. Broader Impacts: Membranes are capable of separating species as a function of their physical and chemical properties when a driving force is applied, and they enable filtration for removal of colloids, cells and molecules. The major concern associated with the use of membranes is fouling. Membrane fouling adversely affects membrane performance and cost through loss in flux, increase in pressure, and cleaning frequency. Developing a membrane process with low fouling is the ?holy grail? of membrane research. The results of the proposed project will be disseminated through the training of graduate and undergraduate students, peer-reviewed publications and conference presentations, and the education of young underrepresented migrant students on drinking water problems and treatment.