P-mSA/mCS双极膜的制备及其在一价、二价离子分离中的应用

以五氧化二磷、磷酸三乙酯和磷酸为反应剂, 制备了磷酸化海藻酸钠(P-SA), 经二茂铁离子改性后作为阳膜层(P-mSA); 用乙酰基二茂铁改性壳聚糖制备了阴膜溶胶(mCS). 将阴膜溶胶流延于阳膜层上, 制备了P-二茂铁-SA/乙酰基二茂铁-CS双极膜(P-mSA/mCS BPM). 测定了双极膜的红外光谱、接触角、电荷密度、离子交换容量与交流阻抗. IR与接触角的分析结果表明, SA经磷酸化后, 亲水性能得到了显著提高. 将P-mSA/mCS BPM应用于一价、二价离子的分离, 当压力差为0.3 MPa时, 二价离子的截留率(双极膜截留的离子百分数)为95%, 一价离子的截留率为22%左右.

Preparation of P-mSA/mCS Bipolar Membrane and Its Application in Separating Monovalent and Divalent Ions

A phosphorylated sodium alginate (P-SA) membrane was synthesized using phosphorus pentaoxide, riethyl phosphate and phosphoric acid and then modified by ferrocene. Chitosan (CS) was modified by acetylferrocene. A P-ferrocene-SA/acetylferrocene-CS bipolar membrane, P-mSA/mCS BPM, was prepared by a paste method. The bipolar membrane was characterized by Fourier transform infrared spectroscopy (FTIR), contact angle, charge density, ion exchange capacity and alternating current impedance spectroscopy. Results of FTIR and contact angle measurements showed that the hydrophilic property of SA improved after modification by phosphorylation. P-mSA/mCS BPMwas applied to separate monovalent and divalent ions. The rejection ratios of divalent and monovalent ions were about 95%and 22%, respectively, when the pressure was 0.3 MPa.