Softening of hard water by ion-exchange with strongly acidic cationic resin. Application to the brackish groundwater of the coastal area of El Jadida province (Morocco)

In this work,the resin duolite 206a has been tested for softening,on the one hand,synthetic water containing ca2+ and mg2+,and secondly,brackish groundwater from the coastal area of el jadida province (morocco). after studying the effect of the feed rate on the treatment of synthetic waters based on cacl2,2h2o and mgcl2,6h2o,the effect of salinity and ph on the cationic exchange efficiency was evaluated. the obtained results revealed that the treatment of water by the resin duolite 206a is not overly influenced by the nacl concentrations below 2 g.l-1. however,treatment of water strongly acidic on exchange resin is characterized by a decrease of ca2+ and mg2+ ions removal efficiency because of their competition with h+ ions. groundwater of the coastal area located between sidi-abed and ouled-ghanem of el jadida province (morocco) have ph close to neutral,thus competing with h+ ions is nonexistent when softening on the resin. the treated water at 20 minutes from the start of the filtration,using 20 g of the resin and a flow rate of about 6.1 l.h-1,is characterized by a reduction of approximately 63-70% and 54-55% of ca2+ and mg2+ ions,respectively. beyond this time the residual ionic concentration increases to reach the initial concentration c0. the regeneration tests showed that a solution of nacl at 10 g.l-1 seems very suitable to regenerate rapidly the resin duolite 206a saturated with calcium or magnesium ions.