Recovery of Hg(II) from aqueous solution by complexation-ultrafiltration using rotating disk membrane and shear stability of PMA-Hg complex

Abstract

Copolymer of acrylic acid and maleic acid (PMA) was used to remove Hg²⁺ from aqueous solution by complexation-ultrafiltration (C-UF) through rotating disk membrane (RDM). The effects of P/M (mass ratio of PMA to metal ions), pH and rotation speed (N) on the interception of Hg²⁺ were investigated. The interception could reach 99.7% at pH 7.0, P/M 6 and N less than 1890 r/min. The shear stability of PMA-Hg complex was studied by RDM. The critical rotation speed, at which the interception starts to decrease, was 1890 r/min, and the critical shear rate, the smallest shear rate at which PMA-Hg complex begins to dissociate, was 2.50×10⁵ s⁻¹ at pH 7.0. Furthermore, the critical radii were obtained at different rotation speeds and pHs. The results showed that the critical radius decreased with the rotation speed and increased with pH. Shear induced dissociation coupling with ultrafiltration (SID-UF) was efficiently used to recover Hg²⁺ and PMA.

摘要

用丙烯酸-马来酸共聚物(PMA)作络合剂, 通过旋转盘膜(RDM)采用络合-超滤处理含汞稀溶液。 研究了溶液pH、P/M(PMA 与金属离子质量比)和转速对汞离子截留率的影响。研究表明, 在pH 7.0、 P/M 6 及旋转盘转速小于1890 r/min 的条件下, 汞离子的截留率可达到99.7%。此外, 研究了PMA-Hg 络合物在剪切场中的稳定性。当溶液pH 为7.0 时, PMA-Hg 络合物的临界转速(汞离子的截留率开始 下降时的最小转速)为1890 r/min, 临界剪切速率为2.50×10⁵ s⁻¹。此外, 得到了在不同转速和pH 条件 下的临界半径。结果表明, 临界半径随着转速的增大而减小, 随着pH 值的增加而增大。通过剪切诱 导耦合超滤(SID-UF)方法实现了从PMA-Hg 络合物溶液中分离、回收Hg²⁺和PMA。