Pore model for nanofiltration: History, theoretical framework, key predictions, limitations, and prospects

Wang, Ruoyu; Lin, Shihong

doi:10.1016/j.memsci.2020.118809

Cited by 107 publications

(107 citation statements)

References 128 publications

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“…Nanofiltration (NF) membranes are an effective, pressure-driven membrane separation process [ 33 ], which was developed in the late 1970s. The nanoscale pores in an NF membrane are usually less than 2 nm [ 34 ] and the molecular weight cut-off (MWCO) is typically between 150 and 800 Da [ 35 ]. NF is a separation process ranging between ultrafiltration (UF) and RO, which can partially remove the salt in water due to its size exclusion and charge exclusion [ 35 , 36 , 37 ], especially for sulfate and hardness ions [ 38 ].…”

Section: Introductionmentioning

confidence: 99%

Progress in Research and Application of Nanofiltration (NF) Technology for Brackish Water Treatment

et al. 2021

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Brackish water is a potential fresh water resource with lower salt content than seawater. Desalination of brackish water is an important option to alleviate the prevalent water crisis around the world. As a membrane technology ranging between UF and RO, NF can achieve the partial desalination via size exclusion and charge exclusion. So, it has been widely concerned and applied in treatment of brackish water during the past several decades. Hereon, an overview of the progress in research on and application of NF technology for brackish water treatment is provided. On the basis of expounding the features of brackish water, the factors affecting NF efficiency, including the feed water characteristics, operating conditions and NF membrane properties, are analyzed. For the ubiquitous membrane fouling problem, three preventive fouling control strategies including feed water pretreatment, optimization of operating conditions and selection of anti-fouling membranes are summarized. In addition, membrane cleaning methods for restoring the fouled membrane are discussed. Furthermore, the combined utilization of NF with other membrane technologies is reviewed. Finally, future research prospects are proposed to deal with the current existing problems. Lessons gained from this review are expected to promote the sustainable development of brackish water treatment with NF technology.

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Section: Introductionmentioning

confidence: 99%

Progress in Research and Application of Nanofiltration (NF) Technology for Brackish Water Treatment

et al. 2021

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“…Furthermore, due to divalent cations in the feed solution, the agreement between DSPM fitting and actual results was less than adequate. The model predicted an unreasonably high membrane charge density, and the presence of divalent cations changed the sign of the membrane charge density from negative to positive [ 73 ]. As a result, dielectric exclusion (DE) is used here as a secondary partitioning effect at the membrane-external solution interfaces, which will be discussed in greater detail in the following section.…”

Section: Non-sieving Mechanismmentioning

confidence: 99%

“…Furthermore, as mentioned by Wang, researchers have made many modifications for various scenarios. However, the original DSPM–DE framework remains the most often utilized due to its capabilities of fitting experimental data in most cases [ 73 ].…”

Section: Non-sieving Mechanismmentioning

confidence: 99%

Rejection Mechanism of Ionic Solute Removal by Nanofiltration Membranes: An Overview

et al. 2022

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The toxicity of heavy metals can cause water pollution and has harmful effects on human health and the environment. Various methods are used to overcome this pressing issue and each method has its own advantages and disadvantages. Membrane filtration technology such as nanofiltration (NF) produces high quality water and has a very small footprint, which results in lower energy usage. Nanofiltration is a membrane-based separation technique based on the reverse osmosis separation process developed in the 1980s. NF membranes have a pore size of 1 nm and molecular weight cut off (MWCO) of 300 to 500 Da. The properties of NF membranes are unique since the surface charge of the membranes is dependent on the functional groups of the membrane. The rejection mechanism of NF membrane is unique as it is a combination of various rejection mechanisms such as steric hindrance, electric exclusion, dielectric effect, and hydration mechanism. However, these mechanisms have not been studied in-depth due to their complexity. There are also many factors contributing to the rejection of NF membrane. Many junior researchers would face difficulty in studying NF membrane. Therefore, this paper is designed for researchers new to the field, and will briefly review the rejection mechanisms of NF membrane by both sieving and non-sieving separation processes. This mini-review aims to provide new researchers with a general understanding of the concept of the separation process of charged membranes.

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“…For high concentrations of KCl, the value of Rp is dominated solely by the fixed resistance of 5500 Ω. This could be assigned to resistance of smaller micropore spaces that are not fully electrolyte-filled due to exclusion of cations [19]. Perhaps interestingly, the value of 5500 Ω (equivalent to ĸ = 0.8 Ω −1 m −1 ) is approximately consistent with the transition point for concentration polarisation to be observed (at lower concentration) and not observed (at higher concentration) (vide supra).…”

Section: Microbead Electrochemistry In Aqueous Kclmentioning

confidence: 99%

Electroanalysis with a single microbead of phosphate binding resin (FerrIX™) mounted in epoxy film

Thompson

Mathwig

Fletcher

et al. 2021

J Solid State Electrochem

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Commercial resin microbeads are widely applied in ion exchange and extraction. Here, a single anion-selective and phosphate binding resin microbead (FerrIX™) is mounted into an epoxy membrane and investigated by 4-electrode membrane voltammetry and membrane impedance spectroscopy. Anion transport properties are observed to dominate associated with three distinct potential domains: (I) a low bias ohmic potential domain (dominant at high electrolyte concentration), (II) a concentration polarisation potential domain, and (III) an over-limiting potential domain. Voltammetric responses show transient diffusion-migration features at higher scan rates and quasi-steady state features at lower scan rates. Inherent microbead conductivity is shown to be linked to two resistive elements, electrolyte concentration dependent and independent, in series. The effects of phosphate binding are revealed as transient pattern in impedance spectroscopy data. Preliminary data suggest phosphate concentration-dependent peak features in the imaginary impedance versus frequency plot due to phosphate binding into the microbead. Graphical abstract

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Pore model for nanofiltration: History, theoretical framework, key predictions, limitations, and prospects

Cited by 107 publications

References 128 publications

Progress in Research and Application of Nanofiltration (NF) Technology for Brackish Water Treatment

Progress in Research and Application of Nanofiltration (NF) Technology for Brackish Water Treatment

Rejection Mechanism of Ionic Solute Removal by Nanofiltration Membranes: An Overview

Electroanalysis with a single microbead of phosphate binding resin (FerrIX™) mounted in epoxy film

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