Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
636879 | Journal of Membrane Science | 2009 | 8 Pages |
Abstract
Fixed-site membranes were prepared by UV initiated in situ polymerization of the functional monomers in pores of the poly(propylene) host membranes for the facilitated transport studies. The crosslinker N-N-methylene-bis-acrylamide (5 mol.%) was used to produce the crosslinked stable gel in pores of host poly(propylene) membrane. The ethylene glycol methacrylate phosphate (EGMP) was selected as a functional monomer due to its phosphate group that has strong complexing ability towards lanthanides/actinides ions. However, the transport rate of Eu3+ ions across the EGMP membrane separating feed and receiver compartments of a permeation cell was quite slow due to strong binding of ions with fixed phosphate sites in the membrane. In order to enhance the transport rate of Eu3+ ions across the fixed-site membrane, the EGMP was polymerized along with a co-monomer like 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS), acrylic acid (AA), and methylmethacrylate (MM). It was observed that the presence of sulfonic acid groups (AMPS) along with phosphate groups (EGMP) in 1:1 proportion in the membrane enhanced transport rate of Eu3+ ions significantly. The variation of uptake of Eu3+ ions as a function of feed acidity indicated that the equilibrium selectivity of the fixed-site membrane was not affected by the presence of strong acidic group. The permeability coefficient of Eu3+ ions across the water swollen EGMP + AMPS membrane was found to be 2.69 Ã 10â3 cm sâ1, which is comparable to that reported for carrier facilitated transport of trivalent ions across supported liquid membrane. The perm-selectivity of Eu3+ over Zn2+ ions across EGMP + AMPS membrane from feed containing 0.2 mol Lâ1 HNO3 was not as high as expected from the uptake studies. For example, the uptake of Zn2+ was only 10% as compared to 93% for Eu3+ ions from 0.2 mol Lâ1 HNO3 but the permeability coefficient of Eu3+ ions was only three times higher than that for Zn2+ ions across water swollen EGMP + AMPS membrane. The perm-selectivity of Eu3+ ions over Zn2+ ions could be improved to some extent by incorporating plasticizer in the EGMP + AMPS membrane.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Filtration and Separation
Authors
T. Vasudevan, Sadananda Das, A.K. Debnath, A.K. Pandey,