(401q) Chlorine-Tolerant Block Polymer Nanofiltration Membranes

Authors: 
Zhang, Y., University of Notre Dame
Mulvenna, R., Purdue University
Boudouris, B. W., Purdue University
Phillip, W., University of Notre Dame
The design of next-generation membranes with highly-ordered, well-defined nanostructures is critical to meeting the increasing demand for highly selective separation devices in the water treatment arena. Furthermore, the design of the membrane chemistry is critical to advancing the use of these novel devices. Specifically, chlorine is a commonly used in water treatment systems as a disinfecting agent to reduce the effects of biofouling yet state-of-art nanofiltration membranes, based on polyamide chemistries, cannot tolerate extended periods of exposure to chlorine concentrations above 0.1 ppm. This limited resistance to chlorine necessitates the implementation of costly de-chlorination steps. Therefore, a chemically robust, high-performance nanofiltration device is urgently required to reduce the cost of nanofiltration processes. Due to the ability to self-assemble into a membrane with a well-defined nanostructure, block polymers are ideal candidates to generate highly-selective nanofiltration membranes. In this poster, the careful design of a block polymer chemistry tailored to enable a robust separation profile and to withstand the presence of chlorine will be discussed. In particular, the fabrication of an ultra-thin, self-assembled polyisoprene-b-polystyrene-b-poly(2-acrylamido-ethane-1-1-disfulonic acid) (PI-PS-PADSA) coating atop of a poly(vinylidene fluoride) hollow fiber support generated a filtration device with an extremely high solute selectivity, which is capable of fully fractionating solutes with only 8 Å difference in diameter. The performance of this nanofiltration device upon exposure to sodium hypochlorite solutions for extended periods of time will be discussed. Preliminary results provide strong evidence for the utility of block polymer nanofiltration membranes in chlorine-rich environments.