title: Membrane surface roughness characterization and its influence on ultrafine particle adhesion

Journal: Separation and Purification Technology

Authors: Zhaoxiang Zhong1, Dongyan Li2, Bingbing Zhang3, Weihong Xing3

1College of Food Science and Light Industry
Nanjing University of Technology, Nanjing 210009, P.R. China
2Chemical Engineering department
Nanjing College of Chemical Technology, Nanjing 210048, P. R. China
3College of Chemistry and Chemical Engineering
Nanjing University of Technology, Nanjing 210009, P. R. China
Corresponding author: Weihong Xing

The original and creativity of paper: The paper presented the meaningful information about potential links between membrane surface roughness and filtration performance. 

Summary: 

The surface properties of membrane which are useful for understanding and improving the membrane process were studied. 

Roughness determination
-    The reasonable length of sample should be considered. This is because the increasing of roughness value with respect to sample length is possible.
-    For a sample with short length, only the roughness of the “higher” frequencies was measured. When a longer length was scanned, the roughness caused by additional lower frequencies would also be detected, and then the roughness value of long length sample is higher than the short length sample.
-    Therefore, it is crucial that the same sample length is scanned when comparing the surface roughness for different membranes.

Theoretical approach to the particle deposition
-    Deposit behavior of ultrafine particles on the membrane depends on drag force, adhesive force, and inertial lift force.
-    Drag force and adhesive force move the particle toward the surface of membrane and then cause a friction force. The higher friction force, the higher possibility of particle deposition. 
-    Since the membrane roughness affected the deposition of the particle onto membrane surface, so particle deposition could be controlled by surface roughness modification. 



Application & further study: The information provided in the paper can be used for membrane selection for filtration process.


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