Nanoparticle (NP) additions can substantially improve the performance of reverse osmosis and nanofiltration polyamide (PA) membranes. However, the relative impacts of leading additives are poorly understood. In this study, we compare the effects of
- Award ID(s):
- 1451887
- NSF-PAR ID:
- 10140637
- Date Published:
- Journal Name:
- J. Mater. Chem. A
- Volume:
- 5
- Issue:
- 39
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 20860 to 20866
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract TiO2 andSiO2 NPs as nanofillers in PA membranes with respect to permeate flux and the rejection of organic matter (OM) and salts. Thin‐film nanocomposite (TFN) PA membranes were fabricated using similarly sizedTiO2 15 nm andSiO2(10 – 20 nm) NPs, introduced at four different NP concentrations (0.01, 0.05, 0.2, and 0.5% w/v). Compared with PA membranes fabricated without NPs, membranes fabricated with nanofillers improved membranes hydrophilicity, membrane porosity, and consequently the permeability. Permeability was increased by 24 and 58% with the addition ofTiO2 andSiO2 , respectively. Rejection performance and fouling behavior of the membranes were examined with salt (MgSO4 andNaCl ) and OM (humic acid [HA] and tannic acid [TA]). The addition ofTiO2 andSiO2 nanofillers to the PA membranes improved the permeability of these membranes and also increased the rejection ofMgSO4 , especially for TiO2membranes. The addition ofTiO2 andSiO2 to the membranes exhibited a higher flux and lower flux decline ratio than the control membrane in OM solution filtration. TFN membranes' HA and TA rejections were at least 77 and 71%, respectively. The surface change properties of NPs appear to play a dominant role in determining their effects as nanofillers in the composite membrane matrix through a balance of changes produced in membrane pore size and membrane hydrophilicity. -
null (Ed.)Polymeric membranes for separation of pharmaceutical intermediates/products by organic solvent nanofiltration (OSN) have to be highly resistant to many organic solvents including high-boiling polar aprotic ones, e.g., N- methyl-2-pyrollidone (NMP), dimethylsulfoxide (DMSO), dimethylformamide (DMF). Unless cross-linked, few polymers resist swelling or dissolution in such solvents; however particular perfluoropolymers are resistant to almost all solvents except perfluorosolvents. One such polymer, designated AHP1, a glassy amorphous hydrophobic perfluorinated polymer, has been studied here. Additional perfluoropolymers studied here are hydrophilically modified (HMP2 and HMP3) versions to enhance the flux of polar aprotic solvents. OSN performances of three types of membranes including the hydrophilically modified ones were studied via solvent flux and solute rejection at pressures up to 5000 kPa. The solutes were four active pharmaceutical ingredients (APIs) or pharmaceutical intermediates having molecular weights (MWs) between 432 and 809 Da and three dyes, Oil Blue N (378 Da), Sudan Black B (456 Da), Brilliant Blue R (826 Da). Solvents used were: ethyl acetate, toluene, n- heptane, iso-octane, DMSO, tetrahydrofuran (THF), DMF, acetone, NMP, methanol. Test cells included stirred cells and tangential flow cells. Pure solvent fluxes through three membrane types were characterized using a particular parameter employing various solvent properties. All three membranes achieved high solute rejections around 91–98% at ambient temperatures. HMP2 membrane achieved 95% solute rejection for an API (809 Da) in DMSO at a high temperature, 75 ◦C. A two-stage simulated nanofiltration process achieved 99%+ rejection of a pharmaceutical intermediate (MW, 432 Da) in 75v% NMP-25v% ethyl acetate solution.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/c7ta06307e
