污染控制技术及原理
张立卿,王磊,王旭东,王志盈.城市污水二级出水有机物分子量分布和亲疏水特性对纳滤膜污染的影响[J].环境科学学报,2009,29(1):75-80
城市污水二级出水有机物分子量分布和亲疏水特性对纳滤膜污染的影响
- Effect of molecular weight distribution and hydrophobicity of wastewater effluent organic matter(EfOM) on nanofiltration membrane fouling
- 基金项目：国家高技术研究发展计划(973)项目(No.2008CB417211);国家自然科学基金资助项目(No.50578131);陕西省教育厅专项基金资助项目(No.05Jk243)
- 作者
- 单位
- 张立卿
- 西安建筑科技大学环境与市政工程学院, 西安 710055
- 王磊
- 西安建筑科技大学环境与市政工程学院, 西安 710055
- 王旭东
- 西安建筑科技大学环境与市政工程学院, 西安 710055
- 王志盈
- 西安建筑科技大学环境与市政工程学院, 西安 710055
- 摘要：分别采用分子量分级膜和XAD-8树脂,研究了污水厂二级出水中有机物分子量分布特征及不同分子量分布区间亲疏水有机物的相对含量,考察了分子量分布及亲疏水特性对纳滤膜透水性能的影响.结果表明,二级出水有机物中,小分子亲水性有机物含量最高,小于2k的有机物占总有机物含量的45.61%,其中亲水性物质占28.07%,疏水性物质占17.54%;不同特征的原水分别经纳滤膜过滤,分子量分布对膜污染影响较大,分子量小于30k时,分子量区间越小,比通量衰减越快,分子量大于30k时,分子量区间越大,比通量衰减越快,且分子量较小的有机物通量衰减程度大于分子量较大有机物;在分子量分布相同区间内,亲水性有机物的比通量衰减较慢,说明相同分子量时,膜对亲水性物质的截留率较低,而疏水性物质是引起膜通量衰减的主要原因.
- Abstract：Ultrafiltration membranes with molecular weight cutoff(MWCO) ranging from 2k to 100k and XAD-8 resin were employed to identify the characteristics of the molecular weight(MW) distribution of wastewater effluent organic matter(EfOM).TOC and UV254,as well as the amounts of the hydrophilic/ hydrophobic organic fractions in different MW ranges were measured.Nanofiltration membrane fouling experiments were carried out to investigate the effect of MW distribution and hydrophilic/hydrophobic characteristics of EfOM on membrane flux decline,using the fractionated water samples above.According to the experimental results,45.61% of the total organics are low MW.The percentage of the hydrophilic organics with low MW(less than 2k) was up to 28.07%,while that of the hydrophobic organics was 17.54%.The MW distribution has a significant effect on the membrane fouling.When the MW was less than 30k,the lower the MW,the larger the specific flux decline;while for MW higher than 30k,the higher the MW,the larger the specific flux decline.The degree of flux decline from filtering low MW organics was larger than that for the high MW organics.With the same MW distribution range,specific flux decline of the hydrophilic organics was much slower than that of the hydrophobic organics which indicated that the hydrophobic organic fraction contributes most to the flux decline.
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