Removal of some divalent cations from water by membrane-filtration assisted with alginate.
The removal of divalent metal ions from hard waters or galvanic wastewater by polymer-assisted membrane filtration using alginate was investigated. The ability of this natural polymer to form aggregates and gels in presence of metal ions was studied, in order to carry out metal removal by ultra or micro-filtration. Alginate titrations have shown the presence of amine groups in addition to carboxylates onto the polymer backbone. The binding properties of alginate with divalent cations have been studied, showing an increasing affinity for Ca2+ over Mg2+ as polymer concentration increases, and the relative affinity Pb2+ > or = Cu2+ > Zn2+ > Ni2+. The softening of hard natural waters was achieved successfully and easily, but needs an optimal alginate concentration approximately 4 x 10(-2) M. The alginate powder can be directly added to hard waters. Except for Ni2+, metal-removal was efficient. Polymer regeneration has shown that Cu2+-complexes are labiles.
Fatin-Rouge
Nicolas
N
Laboratoire de Chimie des Matériaux et Interfaces, Université de Besançon, 25030 Besançon, France. nicolas.fatin-rouge@wanadoo.fr
Dupont
Alexandra
A
Vidonne
Alain
A
Dejeu
Jérome
J
Fievet
Patrick
P
Foissy
Alain
A
D000464:Alginates / Q000737:chemistry*; D002413:Cations, Divalent / Q000302:isolation & purification*; D005374:Filtration / Q000295:instrumentation / Q000379:methods*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D008567:Membranes, Artificial
D000464:Alginates; D002413:Cations, Divalent; D006603:Hexuronic Acids; D008567:Membranes, Artificial; D020723:Glucuronic Acid