Abstract
Reduction of nitrate by zero valent iron (Fe$^{0}$ ) has been previously studied, but the proper treatment for the by-product of ammonium has not been reported. However, in terms of nitrogen contamination, ammonium may be regarded as another form of nitrogen contaminants since it can be oxidized to nitrate again under aerobic conditions. This study is focused on simultaneous removal of nitrate and its by-product of ammonium, with the ZanF (Zeolite anchored Fe), a product derived from zeolite modified by Fe(II) chloride followed by reduction with sodium borohydride. Batch experiments were performed without buffer at two different pH condition with ZanF, iron filing, Fe(II)-sorbed zeolite, and pure zeolite to estimate the nitrate reduction and the ammonium production. At higher pH, removal rate of nitrate was reduced in both ZanF and iron filings. ZnF removed 60 % of nitrate at initial pH of 3.3 with no production of ammonium, while iron filing showed equivalent production of ammonium to the reduced amount of nitrate. In terms of nitrogen contamination, ZanF removed about 60 % and 40 % at initial pH of 3.3 and 6, respectively, while iron filing presented negligible removal against total nitrogen including nitrate and ammonium.
