Development of Anti-Fouling, Anti-Microbial Membranes by Chemical Patterning

Membranes are a tool that can help provide clean water to people. However, treatment of impaired waters exposes the membranes to feed waters containing biological and abiotic species, which leads to fouling and loss of membrane productivity over time. Since flux reduction due to fouling is one of the largest costs associated with membrane processes in water treatment, new coatings that limit fouling would have significant economic and societal impacts. Prior studies in this area largely have focused on chemical modifications to the membrane surface, which can be effective but not sufficient for controlling biofouling. A more recent area of research is nano-patterning the membrane surface, inspired by nature (i.e., shark skin). Our hypothesis is combining these two methods (chemical coating and patterning) will yield membrane surfaces that are more effective at biofouling control than either method alone. We will introduce the methodology used to coat membrane surfaces with polymer nanolayers designed to combat biofouling and the methodology used to pattern membrane surfaces. We will explain the chemical switching mechanism and use FTIR to support the reversible switching of the polymer nanolayer between its antifouling and antimicrobial states. We will demonstrate the feasibility of the patterning methodology through AFM

Development of Anti-Fouling, Anti-Microbial Membranes by Chemical Patterning

Over 1 billion people lack access to clean drinking water. Membranes are a tool that can help provide clean water to these people. However, treatment of impaired waters for beneficial use exposes the membranes to feed waters containing biological and abiotic species, which leads to fouling and loss of membrane productivity over time. Since reduction in flux due to fouling is one of the largest costs associated with membrane processes in water treatment, new coatings that limit fouling would have significant economic and societal impacts. Developing these advanced coatings is the focus of our work

Performance of a DOW BW30 RO membrane for the separation of nopinone from methanol-water solvent

Reverse osmosis (RO) membrane technology represents a low-cost, low-energy alternative for the separation of multi-component organic mixtures. However, limited availability of experimental data renders the design of such systems challenging. Moreover, mixtures containing multiple solvent species complicate the applicability of common membrane transport models. This study presents experimental data on the dead-end batch separation of nopinone, a useful intermediate in the chemical industry, from mixed methanol-water solvent across a DOW BW30 RO membrane. Membrane rejection and flux values were determined for feed concentrations of 0.449 – 1.099 M. Data analysis via the solution-diffusion model revealed the presence of convective transport in the investigated system, while the Spiegler- Kedem model obtained a reasonable system description when using a single coefficient for mass transfer description. Accurate calculation of osmotic pressure in the mixed-solvent system was found to impact data analysis due to the effects of non-ideality on the transmembrane driving force. From the Spiegler-Kedem model, permeability coefficient values A and B were yielded of order 10-7 and 10-8, respectively, with a membrane selectivity of ~30 bar-1. Finally, the system’s separation performance in continuous cross-flow was estimated by considering a series of dead-end batch separation units, suggesting feasible system operation at industrial scale