Effect of Ferric Chloride Addition at Critical Fouling Conditions

3 Effect of Ferric Chloride Addition at Critical Fouling Conditions 

Ferric chloride precipitates in solution as amorphous ferric oxyhydroxide and the colloids formed adsorb organics. The interest in adding ferric chloride to the solutions is to remove the organics which were found to cause irreversible fouling due to adsorption on the membrane and precipitation with calcium on the membrane surface. 

The extent of organics deposition depends on the iron concentration. This is similar to the effects observed with calcium concentration, except that no flux decline is observed with FeCfc This may indicate that the structure of the complexes formed is different due to the higher charge of the iron colloids. In the next section deposit morphology studies are reported. 

[mgL ] After Recycle 3 J/Jwo After Experiment After Water Rinse Jw/Jwii DOC Loss [%] ([mgl) 1137254nm Loss [%] ([cm- ]) Calcium Loss r/o] ([mg]) Iron Loss l%] ([mg]) 

---