NaCl溶液的浓度和pH值对不同固定基团阴离子交换膜输运性质的影响,Petroleum Chemistry

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NaCl溶液的浓度和pH值对不同固定基团阴离子交换膜输运性质的影响
Petroleum Chemistry ( IF 1.3 ) Pub Date : 2018-10-12 , DOI: 10.1134/s0965544118110087
S. V. Zyryanova , N. D. Pismenskaya , V. V. Nikonenko

摘要

研究了pH和NaCl溶液浓度对具有不同固定基团性质的MA-40和MA-41阴离子交换异质膜的交换容量和传输特性的影响：MA-40具有弱碱性基团，并且MA-41具有强碱性基团，一小部分弱碱性基团。测量了用各种浓度和pH的NaCl溶液平衡后的膜的交换容量，厚度，水含量和电导率；对于相同的溶液，发现了扩散渗透系数。在1.5至12的pH范围内测量容量；在pH值为3到9的范围内，其余特性保持不变。使用电导率和扩散渗透率的值，计算膜中的离子迁移数。结果表明，在pH 9的外部溶液中，膜的厚度及其电导率最小，而co离子的迁移数最大。这可以通过以下事实来解释：在碱性溶液中，弱碱性官能团会大量去质子化，并且膜的有效容量会大大降低。在pH值下达到最大有效容量\（\ leqslant \） 3; 在这种情况下，MA-40膜中Co离子的传输数是5倍，而MA-41膜中的Co离子的传输数是pH 6和9时相应值的两倍低。 pH值增加的膜是由于弱碱性官能团的质子化程度降低而引起的，与MA-41相比，MA-40膜的变化更为明显。

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The Effect of Concentration and pH of NaCl Solution on the Transport Properties of Anion Exchange Membranes with Different Fixed Groups

Abstract

The effect of pH and concentration of the NaCl solution on the exchange capacity and transport properties of the MA-40 and MA-41 anion-exchange heterogeneous membranes with different nature of fixed groups has been studied: MA-40 has weakly basic groups, and MA-41 has strongly basic groups with a small proportion of weakly basic ones. The exchange capacity, thickness, water content, and electrical conductivity of the membranes equilibrated with NaCl solutions of various concentrations and pH were measured; for the same solutions, the diffusion permeability coefficients were found. The capacity was measured in the pH range from 1.5 to 12; the remaining properties, in the pH range from 3 to 9. Using the values of electrical conductivity and diffusion permeability, the ion transport numbers in the membranes were calculated. It was shown that at the external solution pH 9 the thickness of the membranes and their electric conductivity are minimal, and the transport numbers of co-ions are maximum. This is explained by the fact that in basic solutions weakly basic functional groups are largely deprotonated, and the effective capacity of the membrane is significantly reduced. The maximum effective capacity is achieved at pH \( \leqslant \) 3; in this case, transport numbers of co-ions in the MA-40 membrane are 5-fold, and in the MA-41 membrane, two-fold lower than corresponding values at pH 6 and 9. The changes in the transport properties of the membranes with increasing pH are due to a decrease in the degree of protonation of weakly basic functional groups, these changes are more pronounced for the MA-40 membrane than for MA-41.

更新日期：2018-10-12

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