不同Ca^(2+)浓度范围内海藻酸的超滤膜污染行为研究

Fouling Behavior of Alginic Acid on Ultrafiltration Membrane under Different Ca^(2+) Concentration

为了探明不同Ca^(2+)离子含量范围内海藻酸(SA)对PVDF超滤膜的污染行为,在CaCl_2离子强度为0~50mmo L/L范围内,进行了宏观SA超滤膜过滤实验,并考察了相关膜污染微观作用力以及SA在膜面的吸附行为和吸附层结构特征。结果表明,在较低的离子强度范围内,随着Ca^(2+)离子含量的增大,膜-SA及SA间静电作用力减小,导致SA在膜面的吸附累积速率加剧,且形成致密SA污染层,相应膜污染加剧。相反,在较高的Ca^(2+)离子含量范围内,水合排斥力的出现减缓了膜污染微观作用力,降低了SA在膜面的吸附速率及SA污染层的密实度,进而减缓膜污染。

In order to research the fouling behavior of sodium acid （SA） on PVDF ultrafiltration membrane under a different range of Ca2＋ contents, the ultrafiltration membrane filtration experiments of SA were carried out with the ionic strengths of CaC12 was 0 to 50 mmoL/L. The related micro interaction forces of membrane fouling, the adsorption behavior of SA on membrane surface and the structure characteristics of the adsorption layer were investigated. The results indicated that, the electrostatic forces of membrane-SA and SA-SA decreased with the increase of Ca2~ contents at lower ionic strengths range, resulting in a higher adsorption rate of SA onto the membrane surface and the formation of a denser SA fouling layer, thus the membrane fouling exacerbated. However, at higher range of Ca2＋ contents, the hydration repulsion force was generated, which could weaken the adhesion forces of membrane fouling, the adsorption rate of SA on membrane surface and the compactness of the SA fouling layer decreased, which led to less membrane fouling.