Understanding the chlorination mechanism and the chlorine-induced separation performance evolution of polypiperazine-amide nanofiltration membrane

Liu, Sihua; Wu, Chunrui; Hou, Xiaotong; She, Jingguo; Liu, Su; Lu, Xiaolong; Zhang, Hongwei; Gray, Stephen

doi:10.1016/j.memsci.2018.11.071

Cited by 47 publications

(28 citation statements)

References 41 publications

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“…The small amount of chlorine should be attributed to the chlorine attacking the uncross-linked -NH groups in the polyamide layer to form -NCl groups. 63,64 The TFC NFMs show an obvious decrease in water permeation flux after chlorination (Figure 8a). This result is also consistent with the commercial NFM (NF270) reported in the literature, 44 while the TFN-50 NFMs are almost stable in the same case.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Polyamide Nanofiltration Membranes Incorporated with Cellulose Nanocrystals for Enhanced Water Flux and Chlorine Resistance

Huang

Zhu

et al. 2019

ACS Sustainable Chem. Eng.

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Nanofiltration membranes (NFMs) with a high water permeation flux and salt rejection are extremely desirable due to their low energy consumption and superior separation efficiency in practical applications. Herein, cellulose nanocrystals (CNCs) prepared by the sulfuric acid hydrolysis of microcrystalline cellulose were directly incorporated in the aqueous solution of piperazine for fabricating thin film nanocomposite (TFN) NFMs by interfacial polymerization. The as-fabricated TFN NFMs exhibit obviously rougher and more hydrophilic surfaces compared with those thin film composite membranes without CNCs, resulting in a drastic increase of water permeation flux (106.9 L•m −2 • h −1 ) while keeping a reasonable salt rejection to Na 2 SO 4 (98.3%) and MgSO 4 (96.1%). Moreover, the TFN NFMs maintain a relatively stable water permeation flux after exposure to NaClO solution, benefiting from the remarkable hydrophilicity of CNCs. This study conveys that those easy-to-prepare, acid−base stabilized, organic nanofillers have a great potential to prepare TFN NFMs for water desalination and purification.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Polyamide Nanofiltration Membranes Incorporated with Cellulose Nanocrystals for Enhanced Water Flux and Chlorine Resistance

Huang

Zhu

et al. 2019

ACS Sustainable Chem. Eng.

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Section: Effect Of Cleaning Agents On Nf Membranementioning

confidence: 99%

“…Liu et al stated that free chlorine only caused chlorination and destroyed the hydrogen bonds on the membrane surface at pH 7, and it did not break the amide bond of the PIP-TMC PA . In addition, Liu et al proposed a chlorination mechanism for the PIP-TMC NF membrane including (1) reversible chlorination and (2) amino hydrogen replaced by hydroxyl eventually generating imino groups, as shown in Figure d . However, Simon et al argued that compared with the MPD-TMC PA, the PIP-TMC NF membrane displayed weaker chlorine resistance due to the lower cross-linking degree .…”

Section: Effect Of Cleaning Agents On Nf Membranementioning

confidence: 99%

“…73 They also found that the cross-linking density of the PIP-TMC NF membrane did not change significantly after the acidic chlorination treatment, and the PA chain flexibility was enhanced, resulting in an improved ductility of the separation layer. 73 Liu et al stated that free chlorine only caused chlorination and destroyed the hydrogen bonds on the membrane surface at pH 7, and it did not break the amide bond of the PIP-TMC PA. 69 In addition, Liu et al proposed a chlorination mechanism for the PIP-TMC NF membrane including (1) reversible chlorination and (2) amino hydrogen replaced by hydroxyl eventually generating imino groups, as shown in Figure 4d. 69 However, Simon et al argued that compared with the MPD-TMC PA, the PIP-TMC NF membrane displayed weaker chlorine resistance due to the lower cross-linking degree.…”

Section: Fouling Removal/mitigation By Cleaning Agentsmentioning

confidence: 99%

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How Do Chemical Cleaning Agents Act on Polyamide Nanofiltration Membrane and Fouling Layer?

Huang

Luo

Chen

et al. 2020

Ind. Eng. Chem. Res.

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Nanofiltration (NF) membranes, especially polyamide (PA) ones, are widely applied in water treatment, food processing, and resource recovery thanks to their excellent separation selectivity to small solutes and high water permeability. However, membrane fouling is inevitable during the long-term operation and limits the large-scale applications of NF technology. Chemical cleaning is considered the most effective way to avoid fouling aggravation and quickly restore membrane permeability on site. However, frequent chemical cleaning would cause reversible/ irreversible changes in the physical and chemical properties of NF membranes, resulting in membrane damage and deterioration of separation performance. Moreover, the PA NF membrane with high selectivity and a relatively low cross-linking degree is more sensitive to chemical cleaning. Many efforts, therefore, have been dedicated to clarifying the effect of chemical cleaning on the NF membrane properties and its separation performance. This review summarizes recent developments in the field and epitomizes the synergistic/inhibitory effect among the chemical cleaning agents on the fouling removal. Besides the practical guides for chemical cleaning of the PA NF membrane, many opportunities to advance the field are also pointed out.

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“…However, the multilayer structure of commercial membranes used in pressure-driven processes (micro-,ultra-and nanofiltration as well as reverse osmosis) makes the determination of the skin layer properties quite tricky [16][17][18]. In order to overcome the difficulty inherent in the analysis of through-pore measurements, an alternative measuring method, known as tangential mode and based on the application of the pressure gradient along the membrane skin layer (and not through the membrane thickness) has been proposed and has become the most widely used technique in membrane science [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Electrokinetic leakage as a tool to probe internal fouling in MF and UF membranes

Rouquié

Liu

Rabiller-Baudry

et al. 2020

Journal of Membrane Science

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Tangential electrokinetic measurements are widely used to characterize membrane fouling as the membrane zeta potential is partly governed by the presence of foulant materials on its surface. However, in the case of porous materials as micro-(MF) and ultrafiltration (UF) membranes, a part of the streaming current flows through the porosity of the membrane during measurements. This under various transmembrane pressures (TMP). A significant impact of the TMP on the internal fouling of a MF PES membrane was highlighted, whereas almost no impact of the TMP was noticed in the case of an UF PAN membrane. The developed methodology using the quantification of the electrokinetic leakage phenomenon allows distinguishing the contributions of internal and external (surface) fouling. These findings offer new application of tangential electrokinetic measurements to gain more insight into the characterization of membrane fouling.

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Understanding the chlorination mechanism and the chlorine-induced separation performance evolution of polypiperazine-amide nanofiltration membrane

Abstract: Two self-made PPA NFMs were employed to study their chlorination processes.  Degradation of PPA NFMs includes chlorine substitution and oxidation of -NH groups. Damaged separation performance of chlorinated PPA NFMs can be partially recovered.

Cited by 47 publications

References 41 publications

Polyamide Nanofiltration Membranes Incorporated with Cellulose Nanocrystals for Enhanced Water Flux and Chlorine Resistance

Polyamide Nanofiltration Membranes Incorporated with Cellulose Nanocrystals for Enhanced Water Flux and Chlorine Resistance

How Do Chemical Cleaning Agents Act on Polyamide Nanofiltration Membrane and Fouling Layer?

Electrokinetic leakage as a tool to probe internal fouling in MF and UF membranes

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