Removal of heavy metals in industrial wastewaters by ion-exchanger graftedtextiles

A special class of grafted textiles was studied in order to remove heavy me tals from industrial wastewaters. Three cation-exchanger textiles (CET) wer e tested in a batch reactor, each carrying carboxylate (R-COO-, Na+), sulfo nate (R-SO3-, Na+) or phosphate (R-O-PO32-, 2Na(+)) functional groups. The study of their behaviour towards Cu(II) and Cd(II) was carried out as a fun ction of time (exchange kinetics) and at equilibrium with increasing metal concentrations (exchange isotherms). After determining the exchange capacit ies and selectivity coefficients of GET, the influence of different paramet ers (the counter-ion and functional group nature, the metal concentration, the presence of different competitors in the solution) on the removal of Cu (II) and Cd(II) was shown. The optimal use conditions of CET were therefore well defined and compared with those of conventional resins. Finally, deso rption studies were performed with various regenerating solutions in order to determine the best conditions for textile regeneration and an optimal he avy metal concentration. These cation-exchanger textiles offer an interesti ng alternative for water treatment by ion-exchange technique. (C) 2001 Else vier Science B.V. All rights reserved.