DK膜对无机盐截留性能的研究

发布时间：2018-03-12 20:51

本文选题：DK膜　切入点：无机盐　出处：《应用化工》2017年02期 　论文类型：期刊论文

【摘要】：采用Desal-DK有机纳滤膜分别对1~200 mol/m3的Na Cl、KCl、K2SO4、Na2SO4、Mg Cl2和Ca Cl2水溶液进行纳滤实验,考察无机盐的类型、浓度和渗透流率对截留率的影响,结合道南细孔-介电DSPM-DE模型计算等效荷电密度(Xd),采用DSPM模型计算等效膜孔半径(rp),研究不同类型无机盐截留率和Xd的关系。结果表明,KCl和Na Cl溶液随着浓度的升高截留率逐渐降低,并趋近于某一定值,在低浓度时主要因为静电屏蔽的作用,在高浓度时主要因为空间位阻作用;Ca Cl2和Mg Cl2溶液随浓度增加截留率先升高后降低,在某一位置取的截留率最大值,主要因为Mg2+/Ca2+和Cl-交替吸附引起静电作用的变化;Na2SO4和K2SO4溶液截留率随着浓度增加而降低,主要因为静电屏蔽作用增强,排斥力降低;渗透流率的变化可以改变截留率的大小,但对荷电密度几乎没有影响,因此不会改变截留率随浓度变化的趋势,荷电密度对溶液浓度有较强的依赖关系;在研究的盐浓度范围内,DK膜膜孔并没有出现增大的现象,因此溶液截留率的变化和膜孔径无明显关系。
[Abstract]:Desal-DK organic nanofiltration membrane was used to study the effects of inorganic salt type, concentration and osmotic flow rate on the retention of NaCl-KCl-K _ 2SO _ 4, Na _ 2SO _ 4, mg Cl2 and Ca Cl2 solutions in aqueous solution of 1 ~ 200 mol/m3, respectively. The equivalent charge density is calculated by combining the DSPM-DE model of fine pore and dielectric in Dongnan, and the radius of equivalent membrane pore is calculated by DSPM model. The relationship between the rejection rate of different inorganic salts and Xd is studied. The results show that the solutions of KCl and NaCl increase with the concentration. The rejection rate decreased gradually, At low concentration, it is mainly due to the effect of electrostatic shielding, and at high concentration it is mainly due to the steric hindrance of Ca Cl2 and mg Cl2 solution, which increases first and then decreases with the increase of concentration, and the maximum rejection rate is obtained at a certain position. Mainly because of the change of electrostatic interaction caused by Mg2 / Ca 2 / C 2 and Cl-alternating adsorption, the rejection rate of Na 2SO 4 and K 2SO 4 solution decreased with the increase of concentration, mainly because of the increase of electrostatic shielding effect and the decrease of repulsive force, and the change of permeation rate could change the rejection rate. However, the charge density has little effect on the charge density, so it will not change the trend of the retention rate changing with the concentration, and the charge density has a strong dependence on the concentration of the solution, and there is no increase in the pore of DK membrane in the range of salt concentration studied. Therefore, there is no obvious relationship between the change of solution rejection rate and the pore size of the membrane.
【作者单位】：南京工业大学材料化学工程国家重点实验室;
【基金】：国家支撑计划(2013BAE11B03)
【分类号】：TQ051.893

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