Quantifying functional groups in the active layer of polyamide nanofiltration membranes via the dye adsorption method

Abstract

Ionized amine group (R-NH₂) and carboxyl group (R-COOH) within the active layer of polyamide (PA) nanofiltration membranes result in the formation of positive (R-{\text{NH}}_{\text{3}}^{+}) and negative (R-COO⁻) functional groups, respectively, which determines membrane performance and is essential for membrane fabrication and modification. Herein, a facile dye adsorption/desorption method using Orange II and Toluidine Blue O dyes was developed to measure the densities of R-NH₂, R-{\text{NH}}_{\text{3}}^{+}, R-COOH, or R-COO⁻ on surfaces of six PA membranes, and the correlation between the density of such groups and the zeta potential was established. The dye adsorption method was proven reliable due to its lower standard deviation, detection limit, and quantification limit values. Furthermore, the densities of R-{\text{NH}}_{\text{3}}^{+} or R-COO⁻ under different pH values were measured, fitting well with results calculated from the acid-base equilibrium theory. Additionally, a correlation was established between the net surface density ([R-{\text{NH}}_{\text{3}}^{+}] – [R-COO⁻]) and the surface charge density (σ) calculated via the Gouy–Chapman model based on zeta potential results. The resulted correlation (σ/(mC·m^–2) = (3.67 ± 0.08) × ([R-{\text{NH}}_{\text{3}}^{+}] − [R-COO⁻])/(nmol·cm^–2) + (0.295 ± 0.08)) effectively predicts the σ value of the membrane. This study provides a facile and reliable dye adsorption method for measuring the density of R-NH₂, R-{\text{NH}}_{\text{3}}^{+}, R-COOH, or R-COO⁻, enabling an in-depth understanding of membrane charge properties.

Graphical abstract

Keywords

carboxyl group / amine group / dye-adsorption method / charge property

References

[1] Yue L P, Kong F, Wang Y, . PTSA-mediated interfacial catalytic polymerization of crystalline dense covalent organic framework membranes for enhanced desalination.Journal of Membrane Science, 2023, 685: 121877

[2] Ren Y, Qi P, Wan Y, . Planting anion channels in a negatively charged polyamide layer for highly selective nanofiltration separation.Environmental Science & Technology, 2022, 56(24): 18018–18029

[3] Zeng S, Liang X, Zhao M, . Ultrathin PEI-functionalized carboxyl covalent organic framework membranes for efficient CO₂/N₂ separation.Journal of Membrane Science, 2024, 698: 122590

[4] Tang C Y, Kwon Y N, Leckie J O . Effect of membrane chemistry and coating layer on physiochemical properties of thin film composite polyamide RO and NF membranes II.Membrane physiochemical properties and their dependence on polyamide and coating layers. Desalination, 2009, 242(1−3): 168–182

[5] Nulens I, Peters R, Verbeke R, . MPD and TMC supply as parameters to describe synthesis–morphology–performance relationships of polyamide thin film composite membranes.Journal of Membrane Science, 2023, 667: 121155

[6] Zhao C, Zhang Y, Jia Y, . Polyamide membranes with nanoscale ordered structures for fast permeation and highly selective ion-ion separation.Nature Communications, 2023, 14(1): 1112

[7] Tan Z, Chen S F, Peng X S, . Polyamide membranes with nanoscale Turing structures for water purification.Science, 2018, 360(6388): 518–521

[8] Jun B M, Cho J, Jang A, . Charge characteristics (surface charge vs.zeta potential) of membrane surfaces to assess the salt rejection behavior of nanofiltration membranes. Separation and Purification Technology, 2020, 247: 117026

[9] Wang Z, Xiao K, Wang X M . Role of coexistence of negative and positive membrane surface charges in electrostatic effect for salt rejection by nanofiltration.Desalination, 2018, 444: 75–83

[10] Xu J, Wang Z, Wang J, . Positively charged aromatic polyamide reverse osmosis membrane with high anti-fouling property prepared by polyethylenimine grafting.Desalination, 2015, 365: 398–406

[11] Li Q, Liu Y, Jia Y, . High performance Li⁺/Mg²⁺ separation membrane by grafted short chain amino-rich monomers.Journal of Membrane Science, 2023, 677: 121634

[12] Coronell O, Gonzalez M I, Marinas B J, . Ionization behavior, stoichiometry of association, and accessibility of functional groups in the active layers of reverse osmosis and nanofiltration membranes.Environmental Science & Technology, 2010, 44(17): 6808–6814

[13] Lu D, Ma T, Lin S, . Constructing a selective blocked-nanolayer on nanofiltration membrane via surface-charge inversion for promoting Li⁺ permselectivity over Mg²⁺.Journal of Membrane Science, 2021, 635: 119504

[14] Yao X, Gonzales R R, Sasaki Y, . Surface modification of FO membrane for improving ammoniacal nitrogen (NH4+-N) rejection: investigating the factors influencing NH4+-N rejection.Journal of Membrane Science, 2022, 650: 120429

[15] Coronell O, Mariñas B J, Zhang X J, . Quantification of functional groups and modeling of their ionization behavior in the active layer of FT30 reverse osmosis membrane.Environmental Science & Technology, 2008, 42(14): 5260–5266

[16] Boivin S, Fujioka T . Membrane fouling control and contaminant removal during direct nanofiltration of surface water.Desalination, 2024, 581: 117607

[17] Crossley O P, Thorpe R B, Peus D, . The effect of salinity on the pressure susceptibility of the NF270 membrane.Desalination, 2023, 564: 116804

[18] Ghalamara S, Silva S, Brazinha C, . Valorization of fish by-products: purification of bioactive peptides from codfish blood and sardine cooking wastewaters by membrane processing.Membranes, 2020, 10(3): 44

[19] Gao L, Wang H Y, Zhang Y, . Nanofiltration membrane characterization and application: extracting lithium in lepidolite leaching solution.Membranes, 2020, 10(8): 178

[20] Arkell A, Krawczyk H, Thuvander J, . Evaluation of membrane performance and cost estimates during recovery of sodium hydroxide in a hemicellulose extraction process by nanofiltration.Separation and Purification Technology, 2013, 118: 387–393

[21] Tiraferri A, Elimelech M . Direct quantification of negatively charged functional groups on membrane surfaces.Journal of Membrane Science, 2012, 389: 499–508

[22] Reeves R L, Kaiser R S . Protonation of arylsulfonates in aqueous sulfuric acid.Apparent pK_a values of azo dye sulfonic acids from solubility measurements. The Journal of Physical Chemistry, 1969, 73(7): 2279–2286

[23] Cao Y, Zhang H, Guo S, . A robust dually charged membrane prepared via catechol-amine chemistry for highly efficient dye/salt separation.Journal of Membrane Science, 2021, 629: 119287

[24] Zhu H, Szymczyk A, Balannec B . On the salt rejection properties of nanofiltration polyamide membranes formed by interfacial polymerization.Journal of Membrane Science, 2011, 379(1−2): 215–223

[25] de Jubera A M S, Herbison J H, Komaki Y, . Development and performance characterization of a polyamide nanofiltration membrane modified with covalently bonded aramide dendrimers.Environmental Science & Technology, 2013, 47(15): 8642–8649

[26] Shi Y, Wang X S, Wang X, . Removal of toluidine blue and safranin O from single and binary solutions using zeolite.Crystals, 2021, 11(10): 1181

[27] Chiang H M, Chen T C, Pan S D, . Adsorption characteristics of Orange II and Chrysophenine on sludge adsorbent and activated carbon fibers.Journal of Hazardous Materials, 2009, 161(2−3): 1384–1390

[28] Uchida E, Uyama Y, Ikada Y . Sorption of low-molecular-weight anions into thin polycation layers grafted onto a film.Langmuir, 1993, 9(4): 1121–1124

[29] Sano S, Kato K, Ikada Y . Introduction of functional groups onto the surface of polyethylene for protein immobilization.Biomaterials, 1993, 14(11): 817–822

[30] Chen D, Werber J R, Zhao X, . A facile method to quantify the carboxyl group areal density in the active layer of polyamide thin-film composite membranes.Journal of Membrane Science, 2017, 534: 100–108

[31] Li M, Cheng F, Xue C, . Surface modification of stober silica nanoparticles with controlled moiety densities determines their cytotoxicity profiles in macrophages.Langmuir, 2019, 35(45): 14688–14695

[32] Lu X, Boo C, Ma J, . Bidirectional diffusion of ammonium and sodium cations in forward osmosis role of membrane active layer.Environmental Science & Technology, 2014, 48(24): 14369–14376

[33] Gegenschatz S A, Chiappini F A, Teglia C M, . Binding the gap between experiments, statistics, and method comparison: a tutorial for computing limits of detection and quantification in univariate calibration for complex samples.Analytica Chimica Acta, 2022, 1209: 339342

[34] Dutta M, Upadhyay S, De S . A facile method to estimate the effective membrane pore charge density through surface zeta potential measurement.Journal of Membrane Science, 2021, 637: 119655

[35] Jiang Z, Miao J, He Y, . A pH-stable positively charged composite nanofiltration membrane with excellent rejection performance.RSC Advances, 2019, 9(64): 37546–37555

[36] Luo J Q, Wan Y H . Mix-charged nanofiltration membrane: Engineering charge spatial distribution for highly selective separation.Chemical Engineering Journal, 2023, 464: 142689

[37] Yang Z, Guo H, Tang C Y . The upper bound of thin-film composite (TFC) polyamide membranes for desalination.Journal of Membrane Science, 2019, 590: 117297

[38] Wang Z, You X, Yang C, . Ultrathin polyamide nanofiltration membranes with tunable chargeability for multivalent cation removal.Journal of Membrane Science, 2022, 642: 119971

[39] Wang S Y, Yang Y H, Liang X, . Ultrathin ionic COF membrane via polyelectrolyte-mediated assembly for efficient CO₂ separation.Advanced Functional Materials, 2023, 33(24): 2300386

[40] Guo X, Zhao B, Wang L, . Asymmetrically charged polyamide nanofilm of intrinsic microporosity containing quaternary ammonium groups for heavy metal removal.Journal of Membrane Science, 2024, 698: 122620

[41] Yue L P, Kong F X, Wang Y, . Evolution of morphology, structure, and performance of the COF membranes with monomer concentrations: enabling effective desalination and kinetics analysis.Desalination, 2024, 583: 117712

[42] Kong F X, Yue L, Yang Z, . Cross-linked covalent organic framework-based membranes with trimesoyl chloride for enhanced desalination.ACS Applied Materials & Interfaces, 2021, 13(18): 21379–21389

[43] Smedberg A, Hjertberg T, Gustafsson B . Effect of molecular structure and topology on network formation in peroxide crosslinked polyethylene.Polymer, 2003, 44(11): 3395–3405

[44] Al-Timimi D A H, Alsalhy Q F, AbdulRazak A A, . Novel polyether sulfone/polyethylenimine grafted nano-silica nanocomposite membranes: interaction mechanism and ultrafiltration performance.Journal of Membrane Science, 2022, 659: 120784

[45] Dutta M, Bairoju S, De S . Simplistic determination of the membrane pore charge density in presence of mixture of electrolytes.Journal of Membrane Science, 2023, 675: 121577

[46] Elimelech M, Chen W H, Waypa J J . Measuring the zeta (electrokinetic) potential of reverse osmosis membranes by a streaming potential analyzer.Desalination, 1994, 95(3): 269–286

[47] Al-Amoudi A, Williams P, Mandale S, . Cleaning results of new and fouled nanofiltration membrane characterized by zeta potential and permeability.Separation and Purification Technology, 2007, 54(2): 234–240

[48] Breite D, Went M, Prager A, . The critical zeta potential of polymer membranes: how electrolytes impact membrane fouling.RSC Advances, 2016, 6(100): 98180–98189

[49] Hurwitz G, Guillen G R, Hoek E M V . Probing polyamide membrane surface charge, zeta potential, wettability, and hydrophilicity with contact angle measurements.Journal of Membrane Science, 2010, 349(1−2): 349–357

[50] Zhang M C, Guan K C, Ji Y F, . Controllable ion transport by surface-charged graphene oxide membrane.Nature Communications, 2019, 10: 1253

[51] Gu T, Zhang R, Zhang S, . Quaternary ammonium engineered polyamide membrane with high positive charge density for efficient Li⁺/Mg²⁺ separation.Journal of Membrane Science, 2022, 659: 120802

[52] Zhu C J, Xian W P, Song Y P, . Manipulating charge density in nanofluidic membranes for optimal osmotic energy production density.Advanced Functional Materials, 2022, 32(9): 2109210

[53] Bowen W R, Cao X W . Electrokinetic effects in membrane pores and the determination of zeta-potential.Journal of Membrane Science, 1998, 140(2): 267–273

RIGHTS & PERMISSIONS

Higher Education Press