东江水膜污染物质的确定及污染机理研究

Identification of foulants and fouling mechanisms for ultrafiltration of Dongjiang River water

摘要:

为探讨东江水中引起超滤膜污染的成分及其污染机理, 分别于旱季(11月底)和雨季初期(3月底)对东江水进行超滤膜污染试验, 分析原水、超滤出水及化学清洗液亲疏水性及分子质量分布等水质特性, 并采用膜堵塞模型对膜污染数据进行拟合.高效液相色谱(HPSEC)联合分峰技术(peak fitting)对水质进行分析发现, 东江水中有机物的主要组分为生物聚合物(98 ku)、腐殖质(1 200 u)、腐殖质基本单元(610 u)及低分子中性物质(270 u).尽管雨季时东江水的生物聚合物和腐殖质组分较旱季时有所增多, 两时期试验中的主要膜污染物质都是具有亲水性的生物聚合物及低分子中性物质.膜堵塞模型拟合膜污染过程的结果表明, 生物聚合物在膜表面形成滤饼层及低分子中性组分标准堵塞(窄化膜孔)导致膜污染.

Abstract:

To identify the foulants for ultrafiltration of Dongjiang River water, as well as their fouling process, hydrophobicity and molecular weight distribution of feed, permeate and chemical washing solution were analyzed both in rainy and dry season. High performance size exclusion chromatography (HPSEC) combined with peak fitting was employed as a tool to separate water sample into portions with different molecular weights. The results showed that biopolymers (98 ku), humic substances (1 200 u), building blocks (610 u) and low molecular-weight neutrals (270 u) were the main components in raw water from Dongjiang River, in which the amount of biopolymers and humic substances was higher in rainy season than that in dry season. More importantly, biopolymer and low molecular-weight neutrals were identified the main foulants in total and irreversible fouling during ultrafiltration of Dongjiang River water in both dry and rainy seasons. Furthermore, fitness between fouling data and four classic filtration modeling indicated that cake layer blocking by biopolymer and standard blocking by low molecular-weight neutrals caused fouling during ultrafiltration of Dongjiang River.