Title: Protein fouling of nanofiltration, reverse osmosis, and ultrafiltration membranes?The role of hydrodynamic conditions, solution chemistry, and membrane properties
Journal: Journal of Membrane Science
Authors: Yi-Ning Wanga, b and Chuyang Y. Tanga, b, 

Institute:
a School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore

b Singapore Membrane Technology Centre, Nanyang Technological University, Singapore 639798, Singapore

The original and creativity of paper: The original of this paper is studying fouling behavior at initial stage in a comparison of long term flux behavior. Moreover, this study compared fouling behavior of NF and RO membrane to UF membrane. Thus, the effect of membrane properties on protein fouling was studied as well. 

Summary:
This study designed to study the effect of hydrodynamic conditions, solution chemistry, and membrane properties on protein fouling of NF, RO and UF membranes. Bovine serum albumin (BSA) was used as a model foulant and all experiments were performed under constant pressure.
The results showed that:
-     Initial flux behavior affected by membrane properties, less initial fouling can be found when smoother, more hydrophilic surface, and favorable electrostatic repulsion experienced properties was used. 
-    Long term fouling of NF, RO, and UF membranes was slightly dependence on those membrane properties. 
-    Therefore results of flux behavior indicated that long-term water flux was controlled by the foulant?fouled-membrane while initial flux was controlled by foulant?clean membrane.
-    At pH close to isoelectric point of BSA, fouling was more serious.
-    When Ca2+ and Mg2+ presented in feed solution, they can reduce electrostatic repulsion or the promotion of specific ion interactions resulted in serve fouling.
-     A strong correlation between water flux and the square of zeta potential of BSA (ζ2) was observed. Therefore, the ζ2 can be used as an indicator for predicting the long term fouling behavior.
Contribution: The paper provided useful information of protein (BSA) fouling behaviors (both initial and long term fouling. Moreover, the paper suggested the square of zeta potential of BSA as an indicator for predicting the long term fouling behavior. 

By Monruedee Moonkhum
Email: moon@gist.ac.kr