丙烯酸-马来酸酐共聚物络合超滤分离水溶液中Pb2+和Zn2+的实验研究

采用丙烯酸-马来酸酐共聚物(PMA)为络合剂, 研究络合超滤技术对水溶液中Pb²⁺和Zn²⁺的分离效果、竞争络合效应以及外加盐对分离效果的影响。以两种金属离子截留率之差表示分离率, 以单一金属离子溶液中离子截留率与混合溶液中该离子的截留率之差表示金属离子间的竞争强度。结果表明: 随着PMA浓度增加, 两种金属离子的分离率先增大后减小, 当PMA浓度为200 mg/L时, 分离率达到最大值, 为54.47%。pH从2增加到6时, 分离率先增大后减小, 且在H=4时达到最大, 为71.34%。两种金属离子的竞争效应随pH及PMA浓度的增加先增强后减弱, 在pH=5, PMA浓度为200 mg/L时, 混合溶液中两种离子竞争效应最强。外加Na₂SO₄对分离率有较大影响, 随着 n(Na₂SO₄)增大分离率增加, 随后基本保持不变, 在n(Na₂SO₄)=0.06 mol/L时, 分离率达到最大值, 为97.677%。加入Na₂SO₄减弱了Zn²⁺的竞争络合能力, 有利于两种金属离子的分离。

Separation of Pb2+ and Zn2+ by Using Polymer-Enhanced Ultrafilation

Polyelectrolyte-enhanced ultrafiltration (PEUF) was investigated to separate Pb²⁺ and Zn²⁺ from aqueous solutions by PMA as a chalenting agent. Effects of pH, concentrations of PMA and the added sault on seperation rate (S_r) was studied. S_r inceased gradually before the PMA concentration reached 200 mg/L, and then it decreased, the best S_r value is 54.47%. At pH between 2 to 6, S_r increased gradually with pH reached a maxium value, and then deceased, It was preferable for the selective separation to control pH=4, and the S_r value is 71.34% at this time. PMA and pH play important roles in competitive complexation between Pb²⁺ and Zn²⁺, the increased concentration of PMA and pH enhanced the competitive complexation, when PH reached to 5, PMA concentration is 200 mg/L, the competitive complexation of Zn²⁺ was lowest. The concentration of the added sault have an important infect on S_r. The experiment was performed at pH=4 and PMA=200 mg/L, controlled the concentration of Sodium sulphate from 0.01 to 0.08 mol/L,When the concentration of sodium sulphate is 0.06 mol/L, S_r reached the best. The addition of Na₂SO₄ weakened the competitive complexation effect of Zn²⁺.