Zn/Mn/PAA的制备及对铀酰离子的吸附

Preparation of Zn/Mn/PAA and Its Adsorption Performance for UO22+

摘要:

以聚丙烯酸为原料，Zn2+和Mn2+为交联剂，环氧丙烷为促凝剂，采用溶胶-凝胶法制备了一系列锌/锰交联聚丙烯酸多孔聚合物（Zn/Mn/PAA），考察了Zn/Mn/PAA对铀酰离子（UO22+）的吸附性能，并探讨了吸附剂用量、pH、吸附时间、共存离子以及离子浓度对吸附性能的影响。结果表明，Zn2+和Mn2+物质的量比为1：1（交联剂总用量与聚丙烯酸物质的量比为10：1）时，所得样品Zn/Mn/PAA-2对UO22+的吸附性能最优。在pH=4.3，UO22+的初始质量浓度10 mg/L，吸附时间30 min，吸附剂用量为1 g/L，吸附温度25 ℃的优化条件下，Zn/Mn/PAA-2对UO22+的最大去除率为82.3%，吸附动力学符合准二级动力学模型。在其他金属离子存在时，Zn/Mn/PAA-2对UO22+的吸附具有选择性。在不同水样中Zn/Mn/PAA-2对UO22+的最大去除率可达82.8%。5次循环利用后，Zn/Mn/PAA-2对UO22+的去除率和解吸率仍然可分别达65%和72%。

Abstract:

A series of porous polymers based upon polyacrylic acid crosslinked with Zn/Mn (Zn/Mn/PAA) were prepared by sol-gel method using polyacrylic acid as raw material, Zn2+ and Mn2+ as crosslinkers, and propylene oxide as coagulant. The adsorption performance of Zn/Mn/PAA for uranyl ions (UO22+) were then investigated by adjusting adsorbent dosage, pH, adsorption time, coexisting ions and ionic concentration. The results showed that the prepared Zn/Mn/PAA-2 with a molar ratio of Zn2+ to Mn2+ 1:1, the molar ratio of the total amount of crosskinkers to the polyacrylic acid 10:1, exhibited best adsorption performance for UO22+. Under optimal conditions of pH 4.3, initial UO22+ mass concentration 10 mg/L, adsorption time 30 min, adsorbent dosage 1 g/L and adsorption temperature 25 oC, removal rate of UO22 by Zn/Mn/PAA-2 reached maximum of 82.3% with the adsorption kinetics fitting the pseudo-second kinetic model. In presence of other metal ions, Zn/Mn/PAA-2 displayed selective adsorption for UO22+. The maximum removal rate of UO22+ in different water samples could reach 82.8%. After five times of recycling, the removal rate and desorption rate of UO22+ by Zn/Mn/PAA-2 still remained 65% and 72%, respectively.