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Evaluating of the performance of natural mineral vermiculite modified PVDF membrane for oil/water separation by membrane fouling model and XDLVO theory
Journal of Membrane Science ( IF 8.4 ) Pub Date : 2021-09-21 , DOI: 10.1016/j.memsci.2021.119886
Tong Zhang 1 , Jie Zhang 2 , Qiaoying Wang 1 , Hao Zhang 1 , Zhiwei Wang 1 , Zhichao Wu 1
Affiliation  

A novel vermiculite nanoparticles (Verm NPs) modified poly(vinylidene fluoride) (PVDF) ultrafiltration membrane was firstly fabricated via surface coating at pH 7.2–7.3. The dense but porous modified surface formed by controlling the self-polymerization rate of dopamine at relatively weak alkalinity provided both high water flux and rejection rate of BSA, which broke the trade-off between permeability and rejection rate. The contact angle of optimal modified membrane decreased from 69.6° to 45.0°, showing the effectively enhancement of hydrophilicity. By filtrating two kinds of real oil-in-water emulsions, the stable flux of modified membrane was approximately 2 times higher than that of pristine membrane for both low and high concentration oil-in-water emulsions. In addition, the Verm-PVDF membrane also showed a higher removal efficiency of oil and total organic carbon. According to membrane fouling model analysis, the fouling behavior including adsorption, deposition, blockage of membrane pores and formation of cake layer had obviously alleviated after Verm modification for the two kinds of oil-in-water emulsions due to the formation of water layer by isomorphism substitution and surface hydroxylation of Verm NPs. Assessed by extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, Verm-PVDF membrane exhibited a higher energy barrier and an extremely strong repulsive force for foulants to overcome in low and high concentration emulsions during fouling. Overall, the improved antifouling ability and separation performance of modified membrane indicated that the inartificial Verm NPs was a robust material for pH-control membrane modification with potential application value in oil/water separation.



中文翻译:

基于膜污染模型和XDLVO理论的天然矿物蛭石改性PVDF膜油水分离性能评价

一种新型蛭石纳米颗粒(Verm NPs)改性聚偏二氟乙烯(PVDF)超滤膜首先通过表面涂层在 pH 7.2-7.3 下制造。通过在相对弱的碱度下控制多巴胺的自聚合速率形成致密但多孔的改性表面,提供了高水通量和 BSA 的截留率,打破了渗透率和截留率之间的权衡。最佳改性膜的接触角从69.6°降低到45.0°,表明亲水性得到有效增强。通过对两种真实的水包油乳液进行过滤,无论是低浓度还是高浓度的水包油乳液,改性膜的稳定通量均比原始膜高约2倍。此外,Verm-PVDF 膜还显示出更高的油和总有机碳去除效率。根据膜污染模型分析,两种水包油型乳液通过同构形成水层,经过Verm改性后,吸附、沉积、膜孔堵塞、滤饼层形成等污染行为明显减轻。 Verm NPs 的取代和表面羟基化。根据扩展的 Derjaguin-Landau-Verwey-Overbeek (XDLVO) 理论评估,Verm-PVDF 膜表现出更高的能量屏障和极强的排斥力,可以在结垢过程中克服低浓度和高浓度乳液中的污垢。总体,

更新日期:2021-09-21
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