การกำจัดไนเตรตในน้ำเสียสังเคราะห์ด้วยกระบวนการโฟโตคะตะลิติก

Abstract

This research investigated the efficiency of nitrate nitrogen \(NO_3^--N) removal by photocatalytic reduction process and Ag doped \TiO_2 \(Ag-TiO_2) nanopowder catalyst. The \Ag-TiO_2 was prepared by means of composite colloid deposition method under acid conditions. The \TiO_2 nanopowder was doped by 3 different amounts of Ag: 0.1%, 0.5% and 1.0% of weight per volume (w/v%). The physical characteristics of the prepared \Ag-TiO_2catalyst were inquired into by X-ray fluorescence spectrometer (XRF) and Brunauer, Emmett and Teller analyser (BET) which enabled to identify both the elements and the specific surface areas of the catalyst. The results showed that all of the \Ag-TiO_2 nanopowder catalyst had the desired compounds. Regarding to the investigation of the efficiency of photocatalytic reduction process of nitrate removal with the initial nitrate concentration \([NO_3]_0) of 10, 25, 50, 75 and 100 mg. \L^-1 as N including Ag\-TiO_2 nanopowder catalyst and UVA light source of 1,000 \μW.cm^-2, it was found that this process was able to remove nitrate nitrogen and additionally revealed the highest efficiency of 97.56% with the initial nitrate concentration \([NO_3^-]_0) of 100 mg.\L^-1 as N within 180 minutes. When considering the selectivity (S) of nitrogen conversion in the photocatalytic reduction process within 15 minutes, the selectivity values of other nitrogen were 0.00% of nitrite \(S_NO2^-), 2.13% of ammonia \(S_NH4^+) and 97.87% of nitrogen \(S_N_2), respectively.