The effect of functional groups of humic acid on the fouling of Electrically enhanced membrane filtration
Date Issued
2007
Date
2007
Author(s)
Tseng, Hsiang-Chieh
DOI
zh-TW
Abstract
In this study, humic acid was separated into two water samples: one has higher content of carboxylic functional groups, another has phenolic functional groups by secondary amine anionic exchanger resin. Via electrically enhanced membrane filtration, the efficiency of filtration of humic acid with various ratio of carboxylic and phenolic functional groups under different pore size of membrane and intensity of electric field was investigated.
When electric field was applied, flux increased with the strength of the electric field. Employing pore size of 50KDa and electric field strength of 69.93V/cm, the flux of the sample with more carboxylic functional groups has 43.8% higher than that of water sample with no electric filed applied, and the flux of the sample with more phenolic functional groups has increased 34.9%. Electric field applied shows ascendancy on the rejection of NOM. While 300KDa pore size and 69.93V/cm application were employed, the average DOC rejection rates of water sample for higher carboxylic functional groups and for higher phenolic functional groups are 80.12% and 11.27% respectively. Compared the NOM rejection rate with no electric field applied, the former increased 50.12% before filtration, and the latter only increased 17.5%.
According to the test results , electrically enhanced membrane filtration can appreciably increased the flux and the rejection, especially on the water sample with higher carboxylic functional groups. Furthermore, via electrically enhanced membrane filtration, SUVA level of the water sample containing higher carboxylic functional groups, higher phenolic functional groups, and humic acid solution would be reduced with increasing strength of electric field. It shows that, electric field applied and organic precursors of disinfection by-products have positive correlation.
But, no matter how much strength of electric field was applied, rejection is still relevant to pore size of filter membrane. In briefing, pore size is an important factor to the effectiveness of the rejection. Increasing the flux by slow down the fouling, or the appearance of rejection, no mater in which event, the water with higher carboxylic functional groups has better performance. Comparing the experimental results of electrophoresis, the electrophoretic mobility of water sample with higher carboxylic functional groups is higher than that of phenolic functional groups. A positive correlation between the electrophoretic mobility and the performance of electrically enhanced membrane filtration was recognized.
The conclusion could be drawn as: the technique of electrically enhanced membrane filtration is suitable for the water with higher carboxylic functional groups. Besides, SEM analysis shows that higher carboxylic functional groups water would form unstructured filter cake due to electrophoresis, and slow down the declination of flux without affecting the rejection of NOM.
Subjects
天然有機物
官能基
羧基
酚基
外加電場薄膜程序
薄膜孔徑
Natural organic matter
Functional group
Carboxylic functional groups
Phenolic functional groups
electric Enhanced membrane process
Pore size
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-96-R94541113-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):570f1702b76898f47709cc8e6cee0344