School of Environmental & Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road, No. 13, Xi'an 710055, China; Leibniz Institute of Surface Modification, Permoserstraße 15, Leipzig D-04318, Germany.
School of Environmental & Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road, No. 13, Xi'an 710055, China.
Water Res. 2016 Mar 15;91:203-13. doi: 10.1016/j.watres.2016.01.019. Epub 2016 Jan 12.
To investigate how the characteristics of pregenerated organic fouling layers on nanofiltration (NF) membranes influence the subsequent gypsum scaling behavior, filtration experiments with gypsum were carried out with organic-fouled poly(piperazineamide) NF membranes. Organic fouling layer on membrane was induced by bovine serum albumin (BSA), humic acid (HA), and sodium alginate (SA), respectively. The morphology and components of the scalants, the role of Ca(2+) adsorption on the organic fouling layer during gypsum crystallization, and the interaction forces of gypsum on the membrane surface were investigated. The results indicated that SA- and HA-fouled membranes had higher surface crystallization tendency along with more severe flux decline during gypsum scaling than BSA-fouled and virgin membranes because HA and SA macromolecules acted as nuclei for crystallization. Based on the analyses of Ca(2+) adsorption onto organic adlayers and adhesion forces, it was found that the flux decline rate and extent in the gypsum scaling experiment was positively related to the Ca(2+)-binding capacity of the organic matter. Although the dominant gypsum scaling mechanism was affected by coupling physicochemical effects, the controlling factors varied among foulants. Nevertheless, the carboxyl density of organic matter played an important role in determining surface crystallization on organic-fouled membrane.
为了研究预处理有机污染层在纳滤（NF）膜上的特性如何影响随后的石膏结垢行为，使用有机污染的聚（哌嗪酰胺）NF 膜进行了带有石膏的过滤实验。通过牛血清白蛋白（BSA）、腐殖酸（HA）和海藻酸钠（SA）分别在膜上诱导有机污垢层。研究了结垢物的形态和成分、Ca(2+)在石膏结晶过程中在有机污染层上的吸附作用，以及石膏在膜表面上的相互作用力。结果表明，与 BSA 污染和原始膜相比，SA 和 HA 污染的膜在石膏结垢过程中具有更高的表面结晶倾向，通量下降更严重，因为 HA 和 SA 大分子充当了结晶的核。基于对有机吸附层上 Ca(2+)吸附和粘附力的分析，发现通量下降率和幅度与有机物的 Ca(2+)结合能力呈正相关。尽管石膏结垢的主要机制受到耦合物理化学效应的影响，但在不同的污染物之间，控制因素有所不同。然而，有机物的羧基密度在确定有机污染膜上的表面结晶方面起着重要作用。
