The Influence of Humic Acid Hydrophobicity on Fouling Resistances during Ultrafiltration
Date Issued
2004
Date
2004
Author(s)
Hsiao, Chi-Hung
DOI
zh-TW
Abstract
Fouling is a critical issue during membrane operation. It may reduce permeate flux, lower treatment effeciency, increase operation cost, decrease membrane competitiveness against conventional water treatment process. Fouling level is influenced by membrane material, transmembrane pressure, feed concentration, and water quality. During membrane operation, fouling phenomena will cause acute flux decline. In other words, fouling resistances will rise during the operation. Therefore, to provide better UF efficiency, fouling resistances(R) development should be studied deliberately.
The objective of the research is to analyze the fouling resistances during membrane operation. Three feed with diverse hydrophobicity are filtrated with UF membrane, and the result is analyzed to assess fouling significance in the research.
DAX-8 resin was used to isolate hydrophobic and hydrophilic compounds from commercial humic acid solution. The hydrophobic sample held most dissolved organic carbon, and little DOC was retained in hydrophilic sample. Acute flux decline was observed in the hydrophilic sample during UF operation. This may imply that hydrophilic sample had more sensitiveness to fouling, higher affinity to the membrane stuff, and greater fouling resistances.
Afterwards, fouling resistances were analyzed with series resistances model. The total fouling resistance was divided into four group, and each one represented diverse obstacle during UF operation.
It is observed that the highest total resistance(Rtotal) arose in hydrophilic sample group runs. Thus, it implies that the hydrophilic sample has the most foulants on the membrane. On the other hand, there is no significant diversity between the Rtotal of hydrophobic and humic acid groups. This matches the isolation result, which means that the hydrophobic sample and humic acid solution have similar compositions.
In fouling resistances analysis, the reversible resistance(Rr) is from 14% and 47% of Rtotal, while non-adsorptive resistance, sum of membrane R and reversible R, is over 50% of Rtotal in most runs with hydrophobic and humic acid group. Therefore, adsorption phenomenon may not be the major fouling mechanism in hydrophobic and humic acid group.
Subjects
超過濾
腐植酸
阻力串聯模式
阻力
積垢
親疏水性
series resistances model
resistances
fouling
hydrophobic
humic acid
UF
hydrophilic
Type
thesis
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