Evaluation of ion exchange pretreatment options to decrease fouling of a reverse osmosis membrane

Indarawis, Katrina; Boyer, Treavor H.

doi:10.1080/19443994.2013.867416

Cited by 7 publications

(3 citation statements)

References 18 publications

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“…Precipitative softening to remove divalent cations prior to NF requires chemicals, such as lime, and space for both coagulation/flocculation and sedimentation processes. Ion exchange is simpler than lime softening but increases Na + concentrations in the finished water and produces high salinity regeneration waste streams. , Since NF membranes are currently used not only for NOM removal but also water softening (i.e., removal of multivalent cations), ,, softening pretreatment via NF holds some attraction because membrane systems are modular, scalable, energy efficient, and minimize chemical use, , but fouling, as indicated above, can be problematic.…”

Section: Introductionmentioning

confidence: 99%

Performance of a Hybrid ED–NF Membrane System for Water Recovery Improvement via NOM Fouling Control

Kum

Landsman

et al. 2021

ACS EST Eng.

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Natural organic matter (NOM) complicates water treatment and causes formation of disinfection byproducts (DBPs). NOM is removed well by nanofiltration (NF) but causes extensive membrane fouling, especially in the presence of divalent cations. This research investigated a hybrid electrodialysis-nanofiltration (ED−NF) system to treat freshwaters containing hardness and NOM. ED removes most ions but little to no NOM, and the ED diluate is, then, treated with NF to remove NOM with reduced fouling. Subsequently, some or all of the ED concentrate can be mixed with the NF permeate to increase water recovery, limit NOM concentration (and thereby reduce DBPs), and control the ion content. Compared to NF alone, ED−NF increases product water yield. NF fouling was reduced by the removal of divalent cations in ED. Spectroscopic and resonant scattering measurements of fouled membranes near the calcium K-edge reveal a significant contribution to NF fouling by calcium bridging between carboxyl groups in NOM and on the membrane surface. This novel ED−NF system allows several control "knobs" to increase water recovery and reduce DBP formation potential by adjusting ED water recovery, ED diluate (and concentrate) ionic composition, and the fraction of concentrate remixed with NF permeate to form the product water.

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Section: Introductionmentioning

confidence: 99%

Performance of a Hybrid ED–NF Membrane System for Water Recovery Improvement via NOM Fouling Control

Kum

Landsman

et al. 2021

ACS EST Eng.

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“…MIEX, cation exchange, and combined ion exchange were investigated as pretreatment for RO membranes for groundwater high in DOC, hardness, and salinity. All three processes showed improvements in flux relative to untreated water [107].…”

Section: Combined Ion Exchangementioning

confidence: 98%

Removal of Dissolved Organic Matter by Magnetic Ion Exchange Resin

Boyer

2015

Curr Pollution Rep

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This article provides a state-of-the-art review on the uses of magnetic ion exchange (MIEX) resin in drinking water and wastewater treatment, with emphasis on removal of dissolved organic matter (DOM) from drinking water and wastewater, regeneration efficiency, removal of inorganic and synthetic organic chemicals, comparison with other anion exchange resins, and integration with other physical-chemical processes. Through laboratory jar tests, pilot plant tests, and full-scale installations for a variety of drinking water sources, MIEX resin can achieve 30-80 % removal of dissolved organic carbon (DOC), which is often higher than alum or ferric coagulation. In addition, MIEX resin has been shown to remove hydrophilic, transphilic, and hydrophobic fractions of DOM and a wide range of molecular weight fractions of DOM. As a result, MIEX pretreatment results in substantial reductions in the formation of trihalomethanes and haloacetic acids upon chlorination. MIEX resin can achieve bromide removal in the range of 10-50 %, with higher bromide removal in waters with low DOC, low alkalinity, and low sulfate. However, there are commercially available anion exchange resins that are more selective for bromide than MIEX resin. MIEX resin has been investigated in combination with coagulation, activated carbon adsorption, membrane separation, lime softening, and ozonation. MIEX pretreatment has been shown to reduce downstream chemical requirements and improve the operation of downstream processes. This is most evident for coagulation and ozonation where the coagulant dose can be reduced by 50-75 % and the ozone concentration can be increased by 40-65 %. In general, MIEX pretreatment shows minor reductions in membrane fouling. Future research should continue to investigate the integration of MIEX treatment with other processes.

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“…To optimize treatment of specific waters, pretreatment strategies should be tailored to remove those constituents that contribute to significant membrane fouling. For example, hydrophobic NOM can be removed by coagulation/flocculation, oxidation, and sorption [78][79][80], whereas multivalent cations might require ion exchange and/or electrodialysis pretreatment [43,81,82].…”

Section: Calcium Aggregates Nom On Nanometer Length Scalesmentioning

confidence: 99%

Linking water quality, fouling layer composition, and performance of reverse osmosis membranes

Landsman

Rongpipi

Freychet

et al. 2023

Journal of Membrane Science

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Evaluation of ion exchange pretreatment options to decrease fouling of a reverse osmosis membrane

Cited by 7 publications

References 18 publications

Performance of a Hybrid ED–NF Membrane System for Water Recovery Improvement via NOM Fouling Control

Performance of a Hybrid ED–NF Membrane System for Water Recovery Improvement via NOM Fouling Control

Removal of Dissolved Organic Matter by Magnetic Ion Exchange Resin

Linking water quality, fouling layer composition, and performance of reverse osmosis membranes

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