TITLE:
Donnan Dialysis Removal of Nitrate from Water: Effects of Process Parameters
AUTHORS:
Thouraya Turki, Raghda Hamdi, Mohamed Tlili, Mohamed Ben Amor
KEYWORDS:
Nitrate, Natural Water, Donnan Dialysis, Anion Exchange Membrane
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.6 No.6,
May
21,
2015
ABSTRACT: Excess or lack of levels of nitrate in drinking water is harmful to the human health, the concentration of NO-3 ions must be maintained at 50 mg/l. Donnan dialysis (DD) used as a driving force of the concentration gradient is an effective and simple technique for nitrate removal. In this paper, the transport of nitrate through an AMX anion-exchange membrane has been studied as a function of driving ion nature, receiver phase concentration, flow rate, temperature and agitation rate under Donnan dialysis condition. It was observed that the hydrodynamic conditions and temperature were the main variables affecting the transmembrane flow. As the driving ion, the chloride ion is more efficient than the hydrogeneocarbonate ion. The systematic study of the different parameters involved showed that the nitrate removal efficiency obtained with a feed synthetic nitrate solution (62 ppm) was off 96%. This efficiency slightly decreases for a tap water containing the same nitrate concentration; it was about 84%. This can be attributed to the complex ionic composition of the natural water.