Description of the variation of retention versus pH in nanofiltration of organic acids

Yin, Zhu; Galier, Sylvain; Balmann, Hélène Roux-de

doi:10.1016/j.memsci.2021.119588

Cited by 12 publications

(6 citation statements)

References 49 publications

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“…Increasing the pH to 8 caused the dissociation of the carboxyl group and increased the electronegativity of the molecule (PABA, AA, Figure 2B). Similar results were obtained in the other works [32][33][34]. Xiong et al (2015) reported that acetic acid rejection increased dramatically from 0% to 62% for DL and 0% to 60% for DK with the increase in pH from 3 to 7 [32].…”

Section: Resultssupporting

confidence: 90%

“…30 mg O 2 /L) and a relatively high pH 8. Theoretically, these factors usually increased the retention of the tested compounds [33,34,46]. Nghiem and Coleman (2008) noticed the significant enhancement in rejection of triclosan when the membranes were pre-fouled with the three model organic foulants, namely, bovine serum albumin (BSA), alginate and humic acid.…”

Section: Resultsmentioning

confidence: 99%

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Removal of Organic Compounds with an Amino Group during the Nanofiltration Process

et al. 2021

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The research covered the process of nanofiltration of low molecular weight organic compounds in aqueous solution. The article presents the results of experiments on membrane filtration of compounds containing amino groups in the aromatic ring and comparing them with the results for compounds without amino groups. The research was carried out for several commercial polymer membranes: HL, TS40, TS80, DL from various manufacturers. It has been shown that the presence of the amino group and its position in relation to the carboxyl group in the molecule affects the retention in the nanofiltration process. The research also included the oxidation products of selected pharmaceuticals. It has been shown that 4-Amino-3,5-dichlorophenol—a oxidation product of diclofenac and 4-ethylbenzaldehyde—a oxidation product of IBU, show poor separation efficiency on the selected commercial membranes, regardless of the pH value and the presence of natural organic matter (NOM). It has been shown that pre-ozonation of natural river water can improve the retention of pollutants removed.

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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Removal of Organic Compounds with an Amino Group during the Nanofiltration Process

et al. 2021

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“…Figure a, which includes the membrane isoelectric point (IEP, ∼3.6 − ) and molecules’ p K a for reference, shows how the increase in the chain length of the fatty acids (FAs) tested did not contribute to a decrease in the transport through the polyamide membrane. Zhu et al , recently investigated VFA separation using a Dow NF-45 membrane, where the separation performance was also highly dependent on the solution pH. For the largest fatty acid tested in this study, octanoate, the rejection was as low as 0% when less than 50% of the species were protonated.…”

Section: Resultsmentioning

confidence: 73%

Dual-Functional Nanofiltration and Adsorptive Membranes for PFAS and Organics Separation from Water

et al. 2022

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Challenges associated with water separation technologies for per- and polyfluoroalkyl substances (PFASs) require efficient and sustainable processes supported by a proper understanding of the separation mechanisms. The solute rejections by nanofiltration (NF) at pH values near the membrane isoelectric point were compared to the size- and mass-transfer-dependent modeled rejection rates of these compounds in an ionized state. We find that the low pK a value of perfluorooctanoic acid (PFOA) relates to enhanced solute exclusions by minimizing the presence and partitioning of the protonated organic compound into the membrane domain. The effects of Donnan exclusion are moderate, and co-ion transport also contributes to the PFAS rejection rates. An additional support barrier with thermo-responsive (quantified by water permeance variation) adsorption/desorption properties allows for enhanced separations of PFAS. This was possible by successfully synthesizing an NF layer on top of a poly-N-isopropylacrylamide (PNIPAm) pore-functionalized microfiltration support structure. The support layer adsorbs organics (178 mg PFOA adsorbed/m2 membrane at an equilibrium concentration of 70 mg/L), and the simultaneous exclusion from the NF layer allows separations of PFOA and the smaller sized heptafluorobutyric acid from solutions containing 70 μg/L of these compounds at a high water flux of 100 L/m2-h at 7 bar.

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Section: Textilementioning

confidence: 99%

“…The separation, concentration, and production of hormones and antibiotics [30][31][32] The capture of fibrinogen and coagulation compounds [33][34][35] The production of organic acids [36][37][38] Catalyst recovery [39][40][41] Protein separation [42][43][44] Water treatment Arsenic removal from groundwater [17,45,46] The removal of pesticides from groundwater [47][48][49] Wastewater treatment [19,20,50 A nanofiltration membrane is defined as a microporous medium with characteristics that fall between those of UF and RO. Structurally, NF membranes are asymmetric, featuring an ultra-thin selective layer [57][58][59].…”

Section: Pharmaceuticals and Biotechnologymentioning

confidence: 99%

Comparative Analysis of Donnan Steric Partitioning Pore Model and Dielectric Exclusion Applied to the Fractionation of Aqueous Saline Solutions through Nanofiltration

Saavedra,

Valdés,

Velásquez

et al. 2024

ChemEngineering

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The aim of this study was to analyze, both theoretically and experimentally, the material transport mechanisms governing the separation of ionic species in aqueous solutions using nanofiltration membranes. To interpret the experimental results, the Donnan Steric Partitioning Model (DSPM) and the Dielectric Exclusion Model (DSPM-DE) were applied and computationally simulated in Matlab. Experimental tests were conducted using a pilot-scale system with commercial NF90 membranes. The results indicate that the DSPM better describes the rejection of monovalent ions (sodium and chloride), while the DSPM-DE is more suitable for divalent ions (sulfate and magnesium). Additionally, both models were sensitized to explore the impact of hindrance factors on the rejection of different ionic species. For neutral molecules present in the solution, it was observed that the DSPM and DSPM-DE do not adequately interpret selectivity, suggesting that under such conditions, the electrostatic exclusion mechanism loses significance, with the steric mechanism prevailing.

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Description of the variation of retention versus pH in nanofiltration of organic acids

Cited by 12 publications

References 49 publications

Removal of Organic Compounds with an Amino Group during the Nanofiltration Process

Removal of Organic Compounds with an Amino Group during the Nanofiltration Process

Dual-Functional Nanofiltration and Adsorptive Membranes for PFAS and Organics Separation from Water

Comparative Analysis of Donnan Steric Partitioning Pore Model and Dielectric Exclusion Applied to the Fractionation of Aqueous Saline Solutions through Nanofiltration

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