Abstract:
Nitrogen is one of the important pollutants present in drinking water are runoff from fertilizer use;
leaking from septic tanks, sewage; and erosion of natural deposits. When nitrate is absorbed in to
blood hemoglobin is converted to methemoglobin. Methemoglobin does not carry oxygen efficiently.
This results in reduced oxygen supply to vital tissues such as the brain. Severe methemoglobinemia
(blue baby syndrome) can result in brain damage and death. In recent years, considerable efforts have
been made to remove nitrate in water. The use of zero valent iron to remove nitrate from water
represents one of the latest innovative methods in the reducing .process. The major reduction product
was ammonia. Zero valent iron in contrast with iron powder have some advantages of specific surface
area, high active surface, which lead to a increased denitrification rate of nitrate.
Materials and Methods
Surface titrations
Surface titration was carried out as a function of the concentration of NaCl to determine pH zpc(Point
of Zero net proton Charge).Prior to commencement of a titration 10.0g/l zero valent iron was
NaNO3) strength. The initial pH value is
around 10.0 after equilibration by adding 0.101 mol dm NaOH .Then, surface titration was started
from pH 10.0 to 3.0 while bubbling with N2 gas to prevent any interference from atmospheric CO2.
All titrations were carried out in thermostatic bath at 25.0 °C. At each titration point the data versus
HCl) were measured by an auto titratior. A reverse base
titration with 0.101 mol dm NaOH was performed to return the suspension to the original starting
pH under same experimental conditions. This titration was repeated for three different ionic strength
NaCl).However, only the acid titration data were considered for the
analysis.These data unit for surface charge density was calculated.
