当前位置: X-MOL 学术Sep. Purif. Technol. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Influence of pH and NaCl concentration on boron rejection during nanofiltration
Separation and Purification Technology ( IF 8.6 ) Pub Date : 2020-12-25 , DOI: 10.1016/j.seppur.2020.118248
Le Han , Ju Tian , Chang Liu , Jiuyang Lin , Jia Wei Chew

Nanofiltration (NF) is promising for replacing reverse osmosis for boron removal more effectively and at a higher energy efficiency. However, the interplay of steric and charge effects underlying rejection behaviors of solutes smaller than the membrane pore size remained incompletely understood, which impedes implementation. This study investigated the influence of pH and NaCl concentration on boric acid/borate rejection by the Desal 5DK NF membrane, with acetic acid/acetate (comparable size and charge nature) and glucose (larger and neutral) serving as benchmarks. Filtration experiments demonstrate that varying pH in the range of 3–11 and NaCl concentration up to 100 mM had little effect on glucose rejection (consistently greater than 95%), but affected the two smaller solutes significantly. Increasing pH from 7 to 11 led to 15% higher rejection of charged acetate because of the increased charges of both the membrane and solute, while increasing pH from 3 to 7 gave 30% higher rejection of neutral boric acid due to steric effects stemming from pore-size reduction. The rejections of the neutral boric acid and acetic acid were negligibly affected by NaCl concentration, but rejection decreased by 15% and 50% for the charged borate and acetate, respectively, due to salt-induced pore-swelling.



中文翻译:

pH和NaCl浓度对纳滤过程中硼排斥的影响

纳滤(NF)有望替代反渗透,从而更有效地以更高的能源效率去除硼。然而,对于小于膜孔径的溶质的排斥行为,其空间和电荷效应之间的相互作用尚不完全清楚,这阻碍了实施。这项研究以Desal 5DK NF膜为研究对象,研究了pH和NaCl浓度对Desal 5DK NF膜对硼酸/硼酸盐截留的影响,并以乙酸/乙酸盐(大小和电荷性质相同)和葡萄糖(较大和中性)为基准。过滤实验表明,在3-11范围内改变pH值和高达100 mM的NaCl浓度,对葡萄糖排斥的影响很小(始终大于95%),但对两种较小的溶质有显着影响。由于膜和溶质的电荷增加,pH从7增加到11导致带电荷的乙酸盐截留率提高15%,而pH从3增加到7使由于孔产生的空间效应而使中性硼酸截留率提高30%尺寸缩小。NaCl浓度对中性硼酸和乙酸的排阻影响可忽略不计,但是由于盐引起的孔膨胀,带电荷的硼酸盐和乙酸盐的排阻分别降低了15%和50%。

更新日期:2021-01-11
down
wechat
bug