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Background and Objectives: Nitrate is one of the most groundwater pollutants in world.
Reduction of nitrate to nitrite by microorganisms cause serious health hazards.
Nitrate can be eliminated using either adsorbtion or reduction. In this study,
we investigated the adsorption of nitate on zeolite and the feasibility of
removal improvement using supported zero
valent nano iron on zeolite via the reduction process.
Materials and Methods: The study was done in two phases investigation the
zeolite and modified zeolite with zero valent nano iron in nitrate removal from
water. First, we determined the optimum pH and time then the effect of
adsorbent and nitrate concentration was investigated in one factor at the time.
The adsorption isotherm was calculated according to the optimum condition. The
physical characteristics of adsorbents were determined using SEM and TEM.
Results: The morphology investigation of adsorbent showed that the
particle size of supported zero valent nano iron on zeolite was approximately
30-50 nm in diameter. The best conditions were pH 5, contact time of 120 min
and 15 g/L for zeolite, while pH 3, contact time of 50 min and 7.5 g/L for
supported zero valent nano iron on
zeolite. The isotherm equations revealed that nitrate adsorption follows
Langmiur in both cases.
Conclusion: The supported zero
valent nano iron on zeolite could be considered as a high potential adsorbent
for nitrate because it has several adsorbent sites, and Fe
0 as a
function for nitrate reduction.
