Microgranular Adsorptive Membrane Filtration

微粒吸附膜过滤

• 批准号: 0931739
• 负责人: Mark Benjamin
• 金额: $ 48.3万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0931739&HistoricalAwards=false
• 关键词: Microgranular; Adsorptive; Membrane; Filtration

0931739 BenjaminThe proposed research will both extend the PI's work on novel, adsorption-based methods to reduce fouling of microfiltration (MF) and ultrafiltration (UF) membranes, and explore a more general water treatment approach - dubbed microgranular adsorptive filtration (ìGAF) - that has emerged from the prior research. Microgranular adsorptive filtration is, essentially, the miniaturization of packed bed processes such as granular media filtration or GAC adsorption to a scale where the whole treatment process takes place in a thin (500 µm) layer of powder-sized particles that have been pre-deposited on a membrane surface. In such processes, the membrane serves primarily as the support for the powder, rather than in its conventional role as the primary agent for pollutant removal. The research will investigate three implementations of ìGAF: filtration to remove colloidal and particulate matter (i.e., miniaturization of a rapid sand filter); adsorption to remove trace inorganic and organic contaminants (miniaturization of an ion exchange bed or GAC contactor); and adsorption to remove NOM (replacement of an enhanced coagulation process with a miniaturized packed bed process). The experimental procedures will consist of depositing a layer of the microgranular media on a membrane, passing water through the layer and membrane at a constant flow rate, and determining both the contaminant removal efficiency and the buildup of hydraulic resistance. At the end of a treatment step, the membrane will be backwashed to flush the media out of the system, and a new cycle will be initiated. Parameters to be varied include the thickness of the deposited layer, the hydraulic application rate, the length of the treatment step, and the backwashing time and intensity. Process performance will be assessed based on the contaminant removal efficiency, the pressure buildup during individual treatment steps, and the long-term stability of that pressure profile (i.e., the reversibility of any fouling that occurs). The potential applications of ìGAF are enormous, but have not been recognized in the past for two reasons. First, the tendency to focus on using a single technology to address a single water treatment goal has led to the use of membranes only as tools for contaminant removal. And second, until recently, the cost of membranes has made their use simply as supports for other media economically prohibitive. In prior research on the use of adsorbents to control membrane fouling, the PI found that the adsorbents were efficiently removing the contaminants that the membrane was intended to treat. That led to the realizations that (1) the most efficient treatment approach was to pack as much adsorbent on the membrane as possible, and to use the membrane strictly as a support for the adsorbent, and (2) ìGAF has many potential applications beyond fouling control. These applications, which include particle removal, trace contaminant removal, and pre-treatment of water prior to desalination, can potentially reduce the size, energy demands, and cost of numerous water treatment processes, while simultaneously making them more efficient. Preliminary tests of a few applications have been encouraging. The intellectual merit of the proposed work derives from the understanding that it will promote of the behavior of packed layers on membranes in general, and adsorbent layers in particular. In the past, cake layers have been investigated almost exclusively in the context of how severely they foul membranes. This project will introduce the idea that cake layers can sometimes be enormously beneficial to membrane processes, and in the process will demonstrate how they can solve specific current problems associated with membrane fouling, desalination, and control of trace contaminants. The most significant broader impact of the work will be the dissemination of the whole idea of microgranular adsorptive filtration. Several applications of ìGAF will be investigated in the research, but many others will undoubtedly be recognized and pursued by other researchers who have never previously thought about ìGAF as a realistic process. Beyond this, the research will advance the arsenal of possible treatment technologies for improving the quality of impaired water, will train new professionals in the field, and engage K-12 students in thinking about water supply and water quality.

0931739 Benjamin拟议的研究将扩展PI在新的基于吸附的方法上的工作，以减少微滤（MF）和超滤（UF）膜的污染，并探索一种更通用的水处理方法-称为微颗粒吸附过滤（MSGAF）-这是从先前的研究中出现的。微粒吸附过滤本质上是将填充床过程（如颗粒介质过滤或GAC吸附）小型化，使整个处理过程在预先沉积在膜表面的粉末大小的颗粒薄层（500 µ m）中进行。在这样的过程中，膜主要用作粉末的载体，而不是其作为污染物去除的主要试剂的常规作用。该研究将调查三个实施的CNOGAF：过滤，以消除胶体和颗粒物质（即，快速砂滤器的小型化）;去除痕量无机和有机污染物的吸附（离子交换床或GAC接触器的小型化）;以及去除NOM的吸附（用小型化填充床工艺代替强化凝聚工艺）。实验程序将包括在膜上沉积一层微粒介质，使水以恒定流速通过该层和膜，并确定污染物去除效率和水力阻力的建立。在处理步骤结束时，将反冲洗膜以将介质从系统中冲洗出来，并启动新的循环。待改变的参数包括沉积层的厚度、水力施加速率、处理步骤的长度以及反冲洗时间和强度。工艺性能将基于污染物去除效率、各个处理步骤期间的压力累积和该压力分布的长期稳定性（即，发生的任何结垢的可逆性）。GAF的潜在应用是巨大的，但由于两个原因在过去没有被认识到。首先，专注于使用单一技术来解决单一水处理目标的趋势导致膜仅用作污染物去除的工具。第二，直到最近，膜的成本使它们仅仅作为其他介质的支撑物在经济上受到限制。在先前关于使用吸附剂控制膜污染的研究中，PI发现吸附剂可以有效地去除膜打算处理的污染物。这导致认识到（1）最有效的处理方法是在膜上填充尽可能多的吸附剂，并严格使用膜作为吸附剂的支撑物，除污垢控制外，GAF还有许多潜在的应用。这些应用包括去除颗粒、去除痕量污染物和脱盐前的水预处理，可以潜在地减少许多水处理工艺的尺寸、能源需求和成本，同时使它们更有效。一些应用程序的初步测试令人鼓舞。所提出的工作的智力价值来自于这样的理解，即它将促进膜上的填充层的行为，特别是吸附剂层。在过去，滤饼层几乎完全是在它们污染膜的严重程度方面进行研究的。该项目将介绍滤饼层有时对膜过程非常有益的想法，并在该过程中展示它们如何解决与膜污染，脱盐和痕量污染物控制相关的特定当前问题。这项工作的最重要的广泛影响将是微粒吸附过滤的整个思想的传播。在研究中将调查几个应用程序，但其他许多人无疑将被其他研究人员谁从来没有想过作为一个现实的过程中，ECORGAF的认可和追求。除此之外，该研究将推进可能的处理技术库，以改善受损水的质量，将培训该领域的新专业人员，并让K-12学生思考供水和水质。