Simultaneous Improvement of Antimicrobial, Antifouling, and Transport Properties of Forward Osmosis Membranes with Immobilized Highly-Compatible Polyrhodanine Nanoparticles

Abstract

This work shows that incorporating highly compatible polyrhodanine nanoparticles (PRh-NPs) into a polyamide (PA) active layer allows for fabricating forward osmosis (FO) thin-film composite (TFC)-PRh membranes that have simultaneously improved antimicrobial, antifouling, and transport properties. To the best of our knowledge, this is the first reported study of its kind to this date. The presence of the PRh-NPs on the surface of the TFC-PRh membranes active layers is evaluated using FT-IR spectroscopy, SEM, and XPS. The microscopic interactions and their impact on the compatibility of the PRh-NPs with the PA chains were studied using molecular dynamics simulations. When tested in forward osmosis, the TFC-PRh-0.01 membrane (with 0.01 wt % PRh) shows significantly improved permeability and selectivity because of the small size and the high compatibility of the PRh-NPs with PA chains. For example, the TFC-PRh-0.01 membrane exhibits a FO water flux of 41 l/(m·h), higher than a water flux of 34 l/(m·h) for the pristine TFC membrane, when 1.5 molar NaCl was used as draw solution in the active-layer feed-solution mode. Moreover, the reverse solute flux of the TFC-PRh-0.01 membrane decreases to about 115 mmol/(m·h) representing a 52% improvement in the reverse solute flux of this membrane in comparison to the pristine TFC membrane. The surfaces of the TFC-PRh membranes were found to be smoother and more hydrophilic than those of the pristine TFC membrane, providing improved antifouling properties confirmed by a flux decline of about 38% for the TFC-PRh-0.01 membranes against a flux decline of about 50% for the pristine TFC membrane when evaluated with a sodium alginate solution. The antimicrobial traits of the TFC-PRh-0.01 membrane evaluated using colony-forming units and fluorescence imaging indicate that the PRh-NPs hinder cell deposition on the TFC-PRh-0.01 membrane surface effectively, limiting biofilm formation.

The Role of Membrane-Based Technologies in Environmental Treatment and Reuse of Produced Water

“…Membrane filtration is a physical separation technique which selectively fractionates components from a flowing substance via pores in a continuous structure (Zirehpour et al, 2016;Firouzjaei et al, 2018a;Rahimpour et al, 2018;Mozafari et al, 2019). Membrane separations are categorized by the driving force and the pore size of applied materials (Xu et al, 2008;Pejman et al, 2020a).…”

Membrane processes

“…In an attempt to simultaneously improve antimicrobial, antifouling, and transport properties of FO, Rahimpour et al. (2018) fabricated FO TFC‐PRh membranes, by incorporating highly compatible polyrhodamine NP (PRh‐NPs) into the surface of the TFC‐PRh active layers. Results of the FTIR spectroscopy, SEM, XPS, coupled with molecular dynamic simulations, indicated TFC‐PRh‐0.01 membrane (with 0.01 wt% PRh) exhibited water flux of 41 L m −2 h, higher than a water flux of 34 L m −2 h for pristine TFC membrane.…”

Cu-BTC Metal−Organic Framework Modified Membranes for Landfill Leachate Treatment

“…Membrane process offers significant potential for separation and purification [1]. Compared to conventional separation methods, membrane separation has significant advantages, such as being energy saving, and having high purification, simplicity of operation, superior efficiency, low operation cost, smaller footprint, better effluent quality and low secondary pollution [2][3][4][5]. Therefore, effective separation can be achieved by the membrane process [6,7].…”