Thin film composite membrane compaction in high-pressure reverse osmosis

Davenport, Douglas M.; Ritt, Cody L.; Verbeke, Rhea; Dickmann, Marcel; Egger, Werner; Vankelecom, Ivo F.J.; Elimelech, Menachem

doi:10.1016/j.memsci.2020.118268

Cited by 98 publications

(53 citation statements)

References 80 publications

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“…Extrapolation of the pure water flux curves indicated a non-zero intercept, suggesting that some membrane compaction occurred in all cases, as commonly observed in PA membranes. [48][49] The membranes presented around 98% NaCl rejection regardless of the support layer structures since the PA active layers were prepared under the same conditions. Conversely, as discussed above, the NaCl permeability coefficient increased when high pressure was applied, because of the increased water flux providing for a greater convective flow.…”

Section: Resultsmentioning

confidence: 98%

Composite Membranes with Nanofibrous Cross-Hatched Supports for Reverse Osmosis Desalination

Kim

Heath

Kentish

2020

ACS Appl. Mater. Interfaces

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A novel membrane structure comprised of cross-hatched electrospun nanofibers is developed. We illustrate that this novel structure allows for much higher water permeability when used as a support for reverse osmosis thin-film composite membranes. Reinforcement and lamination of the aligned nanofibres generates mechanically robust structures that retain very high porosity and low tortuosity when applied to high pressure seawater desalination operations. The cross-hatched nanofibre layers support the polyamide active layer firmly and reduce resistance to water flow due to the high porosity, low tortuosity, high mechanical strength and minimal thickness of the structures. The nanofibre composite membrane gives a water flux significantly greater than when a traditional support layer is used, at 99 ± 5 m -2 h -1 with NaCl rejection of 98.7 % at 15.5 bar.

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Section: Resultsmentioning

confidence: 98%

Composite Membranes with Nanofibrous Cross-Hatched Supports for Reverse Osmosis Desalination

Kim

Heath

Kentish

2020

ACS Appl. Mater. Interfaces

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“…The physical compaction in the studied membrane is irreversible as observed by SEM imaging. We did not measure the extent of compaction, but it was reported that compaction could reduce the polysulfone surface porosity by up to ∼95% (Davenport et al, 2020). Furthermore, 20-30% of flux is lost due only to polysulfone compaction within 12-20 h after exposure even at low pressures (17 bar) (Hoek et al, 2008).…”

Section: Scanning Electron Microscopy Imaging Of Cross-sectioned Membranes Adds To Autopsies Informationmentioning

confidence: 99%

Clinical Autopsy of a Reverse Osmosis Membrane Module

et al. 2021

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The desalination of seawater using reverse osmosis membranes is an attractive solution to global freshwater scarcity. However, membrane performance is reduced by (bio)fouling. Membrane autopsies are essential for identifying the type of fouling material, and applying corrective measures to minimize membrane fouling. Information from full-scale membrane autopsies guiding improved plant operations is scant in the formal literature. In this case-study, a reverse osmosis membrane from a full-scale seawater desalination plant with a feed channel pressure drop increase of about 218% over the pressure vessel was autopsied. The simultaneous determination of microbial cells, ATP, and total organic carbon (TOC) abundances per membrane area allowed estimating the contributions of biofouling and organic fouling. The abundance of microbial cells determined by flow cytometry (up to 7 × 108 cells/cm2), and ATP (up to 21,000 pg/cm2) as well as TOC (up to 98 μg/cm2) were homogeneously distributed on the membrane. Inorganic fouling was also measured, and followed a similar coverage distribution to that of biofouling. Iron (∼150 μg/cm2, estimated by ICP-MS) was the main inorganic foulant. ATR-FTIR spectra supported that membrane fouling was both organic/biological and inorganic. High-resolution SEM-EDS imaging of cross-sectioned membranes allowed assessing the thickness of the fouling layer (up to 20 μm) and its elemental composition. Imaging results further supported the results of homogeneous fouling coverage. Moreover, imaging revealed both zones with and without compression of the polysulfone membrane layer, suggesting that the stress due to operating pressure was heterogeneous. The procedure for this membrane autopsy provided a reasonable overview of the diverse contributors of fouling and might be a starting point to building a consensus autopsy protocol. Next, it would be valuable to build a RO membrane autopsy database, which can be used as a guidance and diagnostic tool to improve the management and operation of RO desalination plants.

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“…Once the concentration of the feed exceeds a certain maximum, typically in the range of 70-80 g/L TDS, the osmotic pressure difference between the feed and permeate channels increases so much so that the required applied pressure exceeds the maximum allowable pressure of membranes and other system components. Although specialized membrane modules for high-pressure RO can enable higher feed pressures than conventional RO [7], operating at such high pressures (e.g., 120-150 bar) is expected to be more challenging and costly in terms of practical implementation [25]. An alternative approach to raising the maximum allowable pressure of membrane modules is to reduce the transmembrane osmotic pressure.…”

Section: Overview Of Enhanced Ro Technologies For Minimal/zero Liquid Dischargementioning

confidence: 99%

Pathways for minimal and zero liquid discharge with enhanced reverse osmosis technologies: Module-scale modeling and techno-economic assessment

2021

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While mechanical vapor compression is typically applied for the concentration of brine, new approaches that are less costly and less energy intensive are needed to facilitate minimal and zero liquid discharge. Several variations of reverse osmosis for high-salinity desalination and increasing recovery rates beyond the pressure limitation of conventional RO have been proposed in the literature. The promise of these enhanced RO approaches entails a reduction in energy consumption when compared with thermal desalination methods. In this paper, low-salt rejection reverse osmosis (LSRRO), cascading osmotically mediated reverse osmosis (COMRO), and osmotically assisted reverse osmosis (OARO) were comparatively assessed via module-scale, cost optimization models to gain an accurate perspective of the performance differences between each of these configurations. We quantified the optimal levelized cost of water (LCOW) of each technology for the case of desalinating feedwater at 70 g/L at 75% recovery, which would result in a brine concentration near 250 g/L, a level that allows further treatment with crystallizers. For baseline scenarios, LCOW results for LSRRO, COMRO, and OARO were 6.63, 7.90, and 5.14 $/m 3 of product water, respectively, while the corresponding specific energy consumption (SEC) values were 28.9, 12.8, and 10.3 kWh/m 3 . A sensitivity analysis is also presented. KeywordsBrine management Minimal liquid discharge Zero discharge Zero liquid discharge Osmotically assisted reverse osmosis High-salinity desalination

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Thin film composite membrane compaction in high-pressure reverse osmosis

Cited by 98 publications

References 80 publications

Composite Membranes with Nanofibrous Cross-Hatched Supports for Reverse Osmosis Desalination

Composite Membranes with Nanofibrous Cross-Hatched Supports for Reverse Osmosis Desalination

Clinical Autopsy of a Reverse Osmosis Membrane Module

Pathways for minimal and zero liquid discharge with enhanced reverse osmosis technologies: Module-scale modeling and techno-economic assessment

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