Study on the Effects of DBP Precursors on Fouling Electric Enhanced Membranes
Date Issued
2004
Date
2004
Author(s)
Lee, Hsin-Hua
DOI
zh-TW
Abstract
The effect of humic acid size distribution as electric enhanced membrane process under various membrane pressure and electric voltage was investigated. Humic acid solution was divided into three groups, namely G1-25,000~3,000 Da, G2-3,000~500 Da and G3-500〜50 Da, by means of gel filtration chromatography according to their apparent molecular weight. Ultrafiltration behaviors were analyzed by the resistance-in-series model.
The results showed that flux declined to the extend of initial flux 85%, 78% and 72% with pressure under 47 kPa, 74 kPa and 98 kPa, respectively. Resistance in series model also revealed that irreversible resistance raised from 6 % to 21%. Besides, humic acid removal efficiency decreased with pressure increase.
While treating various molecular size solution at pressure 98 kPa. The order of flux decline was G3> G2 >G1≒ unfractionated solution. It was believed that smaller solute with stronger adsorption to the membrane pores caused serious membrane fouling and flux decline. Smaller molecular could easily pass through 100k Da membrane, thus UV254 and DOC removal efficiency was only 70 % and 47 %, respectively. However, the reversible and weak reversible resistance of the smaller molecule was 33 %, which was higher than 12 % of G1 group. Thus, frequent backwash was a promising way to deal with smaller solute.
When operating the electric enhanced membrane process, electrophoresis and electroosmosis are the main mechanism to enhance the filtration process. Adding 25 V to the system could keep the flux greater than 80 % of initial flux without electric enhanced. Besides, it has capability to reduce NOM precursors containing in permeate. As a result, the electrical enhanced membrane process has the potential for drinking water treatment.
Subjects
腐植酸
外加電場薄膜程序
阻力串聯模式
分子量分布
Resistance in series model
Molecular size distribution
Humic acid
Electric enhanced membrane process
Type
thesis
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