Abstract
It was proposed that ultraviolet(UV) irradiation could reduce nitrate to nitrite in an aqueous solution and that disodium ethylenediamine tetraacetate(EDTA) as an additive assists in the reduction of either nitrate or nitrite. The purpose of this study is to obtain basic data for a practical removal of nitrate and nitrite from industrial wastewater by UV irradiation. It was found that EDTA effectively removes nitrogen species at 1000-fold higher concentrations than the previous concentration examined by Takeda et al. and that glycine and glycolate are also very effective for the removal of nitrogen species. Glycolate was considered to be one of the decomposition products of glycine produced by UV irradiation. Both nitrate and nitrite from ammonium nitrate were completely removed by UV irradiation regardless of pH in most cases, when either of the additives was added with a molar ratio of about 1 to 1 as nitrate to a (N)-CH2COO-unit.
