Protein fouling in carbon nanotubes enhanced ultrafiltration membrane: Fouling mechanism as a function of pH and ionic strength

Abstract

CitationLee J, Jeong S, Ye Y, Chen V, Vigneswaran S, et al. (2016) Protein fouling in carbon nanotubes enhanced ultrafiltration membrane: Fouling mechanism as a function of pH and ionic strength. Separation and Purification Technology. Available: http:// dx.Please cite this article as: J. Lee, S. Jeong, Y. Ye, V. Chen, S. Vigneswaran, T. Leiknes, Z. Liu, Protein fouling in carbon nanotubes enhanced ultrafiltration membrane: Fouling mechanism as a function of pH and ionic strength, Separation and Purification Technology (2016), doi: http://dx. AbstractThe protein fouling behavior was investigated in the filtration of the multiwall carbon nanotube (MWCNT) composite membrane and commercial polyethersulfone ultrafiltration (PES-UF)membrane. The effect of solution chemistry such as pH and ionic strength on the protein fouling mechanism was systematically examined using filtration model such as complete pore blocking, intermediate pore blocking and cake layer formation. The results showed that the initial permeate flux pattern and fouling behavior of the MWCNT composite membrane were significantly influenced by pH and ionic strength while the effect of PES-UF membrane on flux was minimal. In a lysozyme (Lys) filtration, the severe pore blocking in the MWCNT membrane was made by the combined 2 effect of intra-foulant interaction (Lys-Lys) and electrostatic repulsion between the membrane surface and the foulant at pH 4.7 and 10.4, and increasing ionic strength where the foulant-foulant interaction and membrane-fouling interaction were weak. In a bovine serum albumin (BSA) filtration, severe pore blocking was reduced by less deposition via the electrostatic interaction between the membrane and foulant at pH 4.7 and 10.4 and increasing ionic strength, at which the interaction between the membrane and BSA became weak. For binary mixture filtration, the protein fouling mechanism was more dominantly affected by foulant-foulant interaction (Lys-BSA, Lys-Lys, and BSA-BSA) at pH 7.0 and increase in ionic strength. This research demonstrates that MWCNT membrane fouling can be alleviated by changing pH condition and ionic strength based on the foulant-foulant interaction and the electrostatic interaction between the membrane and foulant.Ultrapure water 1. Highlights• The MWCNT membrane was found to have very high sensitivity to the feed properties.• The MWCNT membrane considerably affected the initial flux and fouling behaviour.• Fouling in the MWCNT membrane could be alleviated by controlling solution chemistry.•Fouling was controlled by the membrane-foulant and foulant-foulant interaction.

Characteristics of coconut protein separation process by means of membrane ultrafiltration

“…Considering UF of quasi‐pure coconut protein, which the interaction of the functional group other than amine was neglected, it was obvious that the J * was highest at pH 9.0 due to the strong electrical repulsive interaction between both protein–protein and protein–membrane (ζ‐potential of −36.47 mV for protein, and −66.20 mV for membrane). These interactions hindered the agglomeration, enhanced the solubility, and reduced the particle size of the protein molecules (Figure 7d), thus the deposition of the proteins on the membrane surface was substantially decreased (Lee et al, ). However, the small particles were easier to be clogged in the membrane pore since the R p obtained at pH 9.0 was highest (Table ).…”

Single and binary protein electroultrafiltration using poly(vinyl-alcohol)-carbon nanotube (PVA-CNT) composite membranes

“…Electrostatic interactions, hydrophobic interactions, hydrogen bonding, and π-π interactions are reported to play key roles in CNT/protein binding. Although there are studies suggesting π-π interactions stacking interactions as the main driving force for protein/CNT binding [17,18], the significance of electrostatic interactions in protein binding with single-and multi-walled CNTs has also been reported [19][20][21]. To evaluate the efficacy of EUF CNT-polymer composite membranes in improving membrane performance in protein processing, a study of the effects of upstream protein/CNT binding on the protein transmission through the downstream UF membrane is required.…”

Single and binary protein electroultrafiltration using poly(vinyl-alcohol)-carbon nanotube (PVA-CNT) composite membranes

“…Electrostatic interactions, hydrophobic interactions, hydrogen bonding, and π-π interactions are reported to play key roles in CNT/protein binding. Although there are studies suggesting π-π interactions stacking interactions as the main driving force for protein/CNT binding [17,18], the significance of electrostatic interactions in protein binding with single-and multi-walled CNTs has also been reported [19][20][21]. To evaluate the efficacy of EUF CNT-polymer composite membranes in improving membrane performance in protein As can be seen, unlike electroultrafiltration processes with electrodes on each side of the membrane, the external electric field terminates with the poly(vinyl-alcohol)-carbon nanotube layer, which is upstream of the semipermeable, polymeric membrane.…”