Development of low‐biofouling polypropylene feedspacers for reverse osmosis

Abstract

Microbial fouling, or biofouling, is the accumulation of microorganisms onto material surfaces. The goal of this project was to develop low-biofouling polypropylene (PP) films through the functionalization of PP by a spacer arm with metal chelating ligands charged with copper ions. Virgin and modified PP films were put in contact with 3.0 Â105 Escherichia coli cells/mL solutions for periods of time varying from 24 to 168 h. Fourier transform infrared spectroscopy (FTIR) and x-ray energy dispersive spectroscopy (EDS) were used to verify the functionalization reactions and monitor copper leaching. Direct counts of cells stained with dsDNA showed, invariably, that the microbial attachment to the modified PP films was an order of magnitune lower than on the virgin PP. Further, over a period of time of 2 weeks, no significant amounts of copper leached from the low-biofouling PP films.

An investigation of low biofouling copper-charged membranes for desalination

“…The results of these experiments observed lower rates of flux decline and no significant copper leaching from the feed spacers [19]. The study also observed that modified PP feed spacers had increased the membrane resistance to fouling and biofouling compared to unmodified feed spacers [19], and could potentially increase the performance and longevity while decreasing the operating cost [18]. Since the work presented here was on material development, samples were too small for studies longer than 24-60 h.…”

“…1. Chelate groups are strong Lewis acids, which can form coordinate bonds with the metal ion by sharing three or more pairs of electrons and a polymer ligand must donate unshared electrons to the metal ion to form metalligand bonds [18]. In the group of multidentate ligands, iminodiacetic acid (IDA) holds an aminopolycarboxylate, which offers a secondary amine hydrogen to react with alternate functional groups [7].…”

“…In the group of multidentate ligands, iminodiacetic acid (IDA) holds an aminopolycarboxylate, which offers a secondary amine hydrogen to react with alternate functional groups [7]. Therefore, IDA is attached to the polymer side chain via SN2 reaction between epoxy group of GMA and imide group of IDA [18]. The chelated copper ions inactivate microbial cells by inhibiting DNA reproduction by attacking on protein's thiol groups [25].…”

Development of copper-charged polypropylene feedspacers for biofouling control

“…Among the multidentate ligands, iminodiacetic acid (IDA) possesses one aminopolycarboxylate and provides a reactive secondary amine hydrogen to react with alternate functional groups [4]. Hence, IDA can be more easily introduced to the side chair of a polymer or vinyl monomer via an epoxy group reaction of glycidyl methacrylate (GMA) and IDA [5]. This reaction has two advantages, (1) GMA is a commercial industrial material that is cheaper than any other vinyl monomers that possess an epoxy ring in the side chain; and (2) it produces a vinyl monomer that can be polymerized in the presence of an initiator and can be grafted to activated polymer surfaces.…”

“…The goal of this project was to functionalize PP with copper (Cu) [5] and to demonstrate that Cu-charged PP could be used to make low-biofouling feedspacers for spiral wound elements. In previous proof-of-concept investigations, PP was functionalized using a spacer arm (GMA) and metal chelating ligands (IDA) to which copper was chelated [5].…”