Relating uncharged solute retention of polyelectrolyte multilayer nanofiltration membranes to effective structural properties

Junker, Moritz A.; Vos, Wiebe M. de; Grooth, Joris de; Lammertink, Rob G.H.

doi:10.1016/j.memsci.2022.121164

Cited by 11 publications

(12 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A realistic distribution would also be the one where the random variable (pore size) can hold only positive values. One of the simplest approaches in this context could be the use of a log-normal distribution, which generally fits well for skewed distributions and has been commonly used for porous materials. − The log-normal distribution considering pore radius, r , as the random variable is given as follows: f false( r false) = 1 r σ 2 π exp ( prefix− false( ln false( r false) − μ ) 2 2 σ 2 ) …”

Section: Methodsmentioning

confidence: 99%

Saturation Equation: An Analytical Expression for Partial Saturation during Wicking Flow in Paper Microfluidic Channels

Verma,

Toley

2024

Langmuir

View full text Add to dashboard Cite

The design and fabrication of paper-based microfluidic devices is critically dependent on modeling fluid flow through porous paper membranes. A commonly observed phenomenon is partial saturation, i.e., regions of the paper membrane not being filled completely due to pores of different sizes. The most comprehensive model to date of partial saturation during wicking flow in paper is the Richards equation. However, the solution to the Richards equation requires numerical solvers like COMSOL, which makes it largely inaccessible to the paper microfluidics and lateral flow assay community. There is therefore a need for a simple and appropriate model of partial saturation in paper membranes, easily usable by the wider research community. In the current work, we present an approach to model paper membranes as a bundle of parallel capillaries whose radii follow a two-parameter log-normal distribution. Application of the Washburn equation to the bundle provides a distribution of fluid fronts, which can be used to calculate saturation. Using this approach, we developed the “saturation equation”an explicit analytical expression to calculate saturation as a function of space and time in 1D wicking flow. Experimentally obtained data for spatiotemporal saturation for four different paper materials were fit to this analytical model to obtain parameters for each material. Results obtained from this analytical model match well with both experimental data and numerical results obtained from the Richards equation. The availability of an explicit analytical expression for partial saturation will enable incorporation of the critical phenomenon of partial saturation in the design of paper microfluidic devices.

show abstract

Section: Methodsmentioning

confidence: 99%

Saturation Equation: An Analytical Expression for Partial Saturation during Wicking Flow in Paper Microfluidic Channels

Verma,

Toley

2024

Langmuir

View full text Add to dashboard Cite

show abstract

“…2,9−12 Studies have shown the applicability of these membranes by reporting near-complete removal of microorganisms and viruses under normal conditions as the apparent pore size of NF membranes of 0.5−1 nm is much smaller than the size of microbial contaminants, providing a suitable barrier. 13,14 Membrane integrity is of the utmost importance when implementing membrane processes for wastewater reclamation. While membranes are effective barriers to potentially remove hazardous contaminants, a breakthrough can occur when the membrane system is damaged.…”

Section: Introductionmentioning

confidence: 99%

“…Pressure-driven membrane filtration processes, such as nanofiltration (NF), have increasingly been considered a post-treatment option in wastewater reclamation. ,− Studies have shown the applicability of these membranes by reporting near-complete removal of microorganisms and viruses under normal conditions as the apparent pore size of NF membranes of 0.5–1 nm is much smaller than the size of microbial contaminants, providing a suitable barrier. , …”

Section: Introductionmentioning

confidence: 99%

Evaluation of Membrane Integrity Monitoring Methods for Hollow Fiber Nanofiltration Membranes: Applicability in Gray Water Reclamation Systems

Rutten,

Ojobe,

Hernández Leal

et al. 2023

ACS EST Water

Self Cite

View full text Add to dashboard Cite

Source-separated gray water reclamation using nanofiltration as an advanced post-treatment option has received substantial interest in meeting the growing water demand. During reclamation, membrane integrity is crucial to ensure the water’s safety. This study evaluated several chemical and novel microbial indicators as indirect membrane integrity-monitoring methods for hollow fiber nanofiltration membranes in reclamation schemes. Under normal conditions, high retention of divalent ions and organic matter and near-complete removal of Escherichia coli (E. coli) were observed. Limited removal of the antibiotic gene (ARG) tetO was observed due to low feed concentrations and a higher detection limit (LOD). While 16S rRNA and ARG sul1 were not limited by their LODs, lower removals were observed, most likely due to free-floating DNA passing through the membranes. A broken fiber in a pilot-scale module reduced organic matter and microorganism removal substantially, while flux and ion rejection remained similar. Predictions made using the observed results and a previously proposed model allowed for the evaluation of the selected methods in upscaled reclamation systems. Based on these results, it was concluded that microorganisms could be employed as indicators in indirect membrane integrity-monitoring methods in large-scale reclamation schemes, while UV254nm absorbance (used in organic matter determination) could be a viable solution in pilot-scale systems.

show abstract

“…Nanofiltration membranes have an apparent pore size of 0.5 -1 nm, which allows for the removal of dissolved neutral substances with molecular weights ranging between 100 -5000 Dalton (Da) (or g.mol -1 ) (Junker et al, 2023;Oatley-Radcliffe et al, 2017). Next to steric exclusion, nanofiltration membranes are able to retain substances by electrostatic interactions.…”

mentioning

confidence: 99%

“…Nanofiltration membranes have a surface charge in the presence of a feed solution due to the presence of ionizable groups such as sulphonic acids. This charged surface will lead to an equilibrium between the charges of the membrane and bulk solution and can therefore retain ionic species present in the feed stream, which could be smaller than the membrane's pore size (Junker et al, 2023;Van Der Bruggen et al, 2003).…”

mentioning

confidence: 99%

Nanofiltration of Greywater to Remove Micropollutants

Rutten

View full text Add to dashboard Cite

Global freshwater resources are currently experiencing increasingly high stress due to extreme weather events brought along by climate change and the evergrowing global population. To protect these natural resources while simultaneously meeting the growing global water demand, local solutions, such as the reclamation of domestically produced wastewater, have gained interest.When considering wastewater reclamation, implementing source-separated sanitation concepts, where toilet water (blackwater) is separately collected from all other sources of domestic water (greywater), can enhance the ease of recovery of nutrients, energy, and water. Effective biological greywater treatment systems have been developed and implemented in the past decades, opening the door to the potential reuse of this stream has limited the full-scale adoption of greywater treatment plants for water reclamation. Micropollutants consist of a large group of natural and anthropogenic substances with a molecular weights up to 800 g.mol -1 , such as pharmaceuticals like diclofenac and personal care products like galaxolide. These substances are found at trace concentration (ng.L -1 -µg.L -1 ) in wastewater and could have potential detrimental effects on the environment when discharged. Therefore, advanced post-treatment solutions are required to reduce the continuous discharge of micropollutants by treatment plants and limit the risks posed by these substances during reuse. One promising post-treatment technology is the use of hollow fiber nanofiltration membranes.These newly developed membranes have proven to be effective barriers for micropollutants in lab-scale experiments and have recently become commercially available for large-scale applications. However, translating these lab-scale results, which were mainly performed using synthetic water matrices, to realworld applications is not straightforward. Further knowledge needs to be acquired to determine the role these membranes can play in greywater treatment systems. General Introduction1.1. Water as an essential resource 1.2. Greywater 1.3. Pressure driven membrane processes 1.4. Polyelectrolyte multilayer based nanofiltration membranes 1.5. Implementation of hollow fiber nanofiltration in greywater treatment 1.6. Thesis outline 2. Influence of dominant salts on the removal of trace micropollutants by hollow fiber nanofiltration Abstract 2.1. Introduction 2.2. Materials and Methods 2.3. Results and Discussion 2.4. Conclusion 3. Retention of micropollutants by polyelectrolyte multilayer based hollow fiber nanofiltration membranes under fouled conditions Abstract 3.1. Introduction 3.2. Materials and Methods 3.3. Results and Discussion 3.4. Conclusions and Outlook xiv 4. Evaluation of membrane integrity monitoring methods for hollow fiber nanofiltration membranes: applicability in greywater reclamation systems Abstract 4.1. Introduction 4.2. Materials and Methods 4.3. Results and Discussion 4.4. Conclusion 5. One year experience with advanced greywater treatment: the removal of micropollutants Ab...

show abstract

Relating uncharged solute retention of polyelectrolyte multilayer nanofiltration membranes to effective structural properties

Cited by 11 publications

References 76 publications

Saturation Equation: An Analytical Expression for Partial Saturation during Wicking Flow in Paper Microfluidic Channels

Saturation Equation: An Analytical Expression for Partial Saturation during Wicking Flow in Paper Microfluidic Channels

Evaluation of Membrane Integrity Monitoring Methods for Hollow Fiber Nanofiltration Membranes: Applicability in Gray Water Reclamation Systems

Nanofiltration of Greywater to Remove Micropollutants

Contact Info

Product

Resources

About