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

University Of Toledo, Toledo OH

Investigators

Abstract

CBET-0754387 Escobar Development 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.