LIGAND-MODIFIED POLYELECTROLYTE-ENHANCED ULTRAFILTRATION WITH ELECTROSTATIC ATTACHMENT OF LIGANDS .1. REMOVAL OF CU(II) AND PB(II) WITH EXPULSION OF CA(II)


TUNCAY M., CHRISTIAN S., TUCKER E., TAYLOR R., SCAMEHORN J.

LANGMUIR, vol.10, no.12, pp.4688-4692, 1994 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 10 Issue: 12
  • Publication Date: 1994
  • Doi Number: 10.1021/la00024a049
  • Title of Journal : LANGMUIR
  • Page Numbers: pp.4688-4692

Abstract

A water-soluble mixture of a cationic polyelectrolyte, poly(diallyldimethylammonium chloride) or PDADMAC, and an anionic ligand, 4,5-dihydroxy-1,3-benzenedisulfonic acid, or Tiron, is used as an agent for binding divalent cations, such as Cu2+ and Pb2+. In equilibrium dialysis experiments, the PDADMACT-Tiron mixture is shown to be effective in binding Cu2+ and Pb2+ in the retentate, while enhancing the concentration of the noncomplexed cation, Ca2+, in the permeate. In the pH range employed, the uncomplexed and complexed forms of Tiron exist primarily as divalent anions. As a consequence they are bound electrostatically to the cationic polyelectrolyte, and little of the ligand is lost through the membrane. The effects of pH, cation concentration, and presence of a competing cation (Ca2+), and added NaCl on the retention of Cu2+ and Pb2+ are discussed.