Mechanistic understanding of the adsorption of natural organic matter by heated aluminum oxide particles (HAOPs) via molecular dynamics simulation

Ma, Yunqiao; Velioğlu, Sadiye; Tanis-Kanbur, Melike Begüm; Wang, Rong; Chew, Jia Wei

doi:10.1016/j.memsci.2019.117651

Cited by 16 publications

(32 citation statements)

References 67 publications

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“…Comparing the RMSD values for lysozyme and α‐lactalbumin, those for the latter are lower. This general behavior is in line with earlier studies that reported that lower RMSD values of small foulants (e.g., oil, surfactants, and natural organic matters) are well‐correlated with worse fouling 44,48,63 . Thus, the experimental observation of relatively worse fouling by α‐lactalbumin 18,19 may be related to the lower post‐adsorption RMSD values.…”

Section: Resultssupporting

confidence: 91%

“…In particular, the top and bottom planes of the simulation box are mirror images of the PVDF membrane, allowing the protein to interact with either surface. The center of mass (COM) of each protein was positioned such that the initial protein–membrane separation distance d is approximately 10

Å

for all systems, 48,49 which is sufficient to allow for rotation of the protein in case the initial orientation is not favorable. Specifically, d was quantified as follows based on the z ‐coordinate:

d = \min ((),, z_{upper} - z_{\max}, z_{\min} - z_{lower})

where, z min and z max are the maximum and minimum z ‐coordinate of any atom in the protein, z lower is the maximum z ‐coordinate of any atom in the bottom PVDF plane, and z upper is the minimum z ‐coordinate of any atom in the top PVDF plane.…”

Section: Simulation Methodologymentioning

confidence: 99%

“…Energy minimization was performed first, followed by a canonical ensemble (NVT) run that increases system temperature from 30 to 298 K. The system was subsequently relaxed at 298 K with a 500 ps NVT run, followed by an equilibration NPT (isothermal–isobaric ensemble) run for 1 ns. Nosé–Hoover thermostat and barostat were used to control temperature and pressure with coupling constants of 500 and 100 fs, respectively 48,63 . The production run ensued for 40 ns under the NPT ensemble with a time step of 1 fs.…”

Section: Simulation Methodologymentioning

confidence: 99%

See 2 more Smart Citations

Molecular dynamics study on membrane fouling by oppositely charged proteins

Zydney

Wang

et al. 2021

AIChE Journal

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Membrane fouling continues to hamper the performance of membrane‐filtration processes. A challenge with macromolecular foulants like proteins is that macroscopic characterizations, like net electrical charge, may be poorly correlated with membrane fouling. This necessitates a molecular‐scale analysis of the local interactions. In this study, molecular dynamics simulations have been performed to understand the interactions between two similar‐sized proteins with opposite overall charges (namely, lysozyme and α‐lactalbumin) and a negative‐charged membrane. Surprisingly, the protein–membrane distances and adsorption probabilities of both proteins are similar. Compared with the positive‐charged lysozyme, the negative‐charged α‐lactalbumin exhibits (a) greater protein–membrane attractive interaction energy due to synergy among adsorption sites; (b) lower root‐mean‐squared deviations (RMSD); and (c) greater number of residues that show low root‐mean‐squared fluctuations (RMSF). These results indicate that local interactions are critical and thus highlight the pitfall of using the overall protein characteristics as predictors of membrane fouling.

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Section: Resultssupporting

confidence: 91%

Å

d = \min ((),, z_{upper} - z_{\max}, z_{\min} - z_{lower})

Section: Simulation Methodologymentioning

confidence: 99%

Section: Simulation Methodologymentioning

confidence: 99%

See 1 more Smart Citation

Molecular dynamics study on membrane fouling by oppositely charged proteins

Zydney

Wang

et al. 2021

AIChE Journal

Self Cite

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“…To stabilize the system, energy minimization was performed first with a canonical ensemble (NVT) run at 30 K for 100 ps, followed by another NVT run to bring the system up to room temperature (298 K), after which the system was relaxed at 298 K by another 500 ps NVT run. An equilibration run (i.e., 1 ns isothermal‐isobaric NPT ensemble at 298 K and 1 bar) ensued with temperature and pressure controlled by Nosé–Hoover thermostat and barostat, respectively 43,61,62 . The coupling time constants for the barostat and thermostat were 500 and 100 fs, respectively 63 .…”

Section: Methodsmentioning

confidence: 99%

Membrane fouling by lysozyme: Effect of local interaction

Zydney

Chew

2021

AIChE Journal

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Molecular dynamics simulations were performed to understand the adsorption of positive‐charged lysozyme onto negative‐charged polyvinylidene fluoride membrane at three pH and two ionic strengths. The lysozyme was initialized at six orientations at 10 Å from the membrane and adsorption was deemed to occur when the lysozyme is less than 4 Å from the membrane. Local interactions are clearly important: (i) despite opposite net charges, no adsorption occurs in some cases throughout; (ii) lysozyme‐membrane separation distances differ among the initial orientations of lysozyme; and (iii) the correlation between lysozyme‐membrane interaction energy and adsorption probability is poor. Correspondingly, seven key local adsorption sites on lysozyme were identified. Of the two most common sites, one anchors due to electrostatics, while the other is not electrostatics‐based. Also, different sites are dominant in different feed conditions and have different interaction energies. These results reveal the importance of local interactions in membrane fouling by proteins in different feed conditions.

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“…When a foulant molecule is less mobile, it tends to deposit on membrane surface and leads to fouling. [ 40,41 ] Figure shows the MSDs of SUC and BPA on alumina and graphene surfaces, respectively, by varying roughness. Each MSD curve is averaged over six independent runs, thus mitigating the effect of random diffusion.…”

Section: Resultsmentioning

confidence: 99%

Membrane Fouling: Microscopic Insights into the Effects of Surface Chemistry and Roughness

Wang

Jiang

2021

Advcd Theory and Sims

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Fouling is a major obstacle and challenge in membrane‐based separation processes. Caused by the sophisticated interactions between foulant and membrane surface, fouling strongly depends on membrane surface chemistry and roughness. Current studies in the field have been largely focused on polymer membranes. Herein, a molecular dynamics simulation study is reported for fouling on alumina and graphene membrane surfaces during water treatment. For two foulants (sucralose and bisphenol A), it is found that the fouling on alumina surfaces is reduced with increasing surface roughness; however, the fouling on graphene surfaces is enhanced by roughness. It is unravelled that the foulant–surface interaction becomes weaker in the ridge region of a rough alumina surface, thus allowing foulant to leave the surface and reducing fouling. Nevertheless, such behavior is not observed on a rough graphene surface because of strong foulant–graphene interaction. In addition, with increasing roughness, the hydrogen bonds between water and alumina surface are found to increase in number as well as stability. This simulation study reveals that surface chemistry and roughness play a crucial role in membrane fouling, and the microscopic insights are useful for the design of new membranes toward high‐performance water treatment.

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Mechanistic understanding of the adsorption of natural organic matter by heated aluminum oxide particles (HAOPs) via molecular dynamics simulation

Cited by 16 publications

References 67 publications

Molecular dynamics study on membrane fouling by oppositely charged proteins

Molecular dynamics study on membrane fouling by oppositely charged proteins

Membrane fouling by lysozyme: Effect of local interaction

Membrane Fouling: Microscopic Insights into the Effects of Surface Chemistry and Roughness

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