Resumen de Degradation of edta in a total chlorine free cellulose pulp bleaching effluent by uv/h2o2 treatment
Carolina Baeza, Claudia Oviedo, Claudio Zaror, Jaime Rodríguez, Juanita Freer
Degradation of EDTA in a Total Chlorine Free (TCF) cellulose pulp bleaching effluent, using UV and UV/H2O2 in presence and absence of iron, was studied. All experiences were conducted in an annular photolytic reactor at pH 9, 20°C, and 0.38 mM (110 mgL-1) EDTA concentration. EDTA degradation followed a first order apparent kinetics, with rate constant in the range of 0.02-0.72 min-1, depending on the initial hydrogen peroxide concentration and iron content. UV treatment without peroxide yielded 100 % degradation of Fe(III)-EDTA in 40 minutes of reaction, but low COD (8 %) and TOC (13 %) removal. Peroxide addition (3.3 mM)increased Fe(III)-EDTA degradation rates by UV treatment, resulting in 100% removal after 20 minutes, and greater COD (28 %) and TOC (36 %) reductions. In absence of iron, peroxide addition was required to obtain EDTA degradationyields above 50% after 1 h treatment. Results presented here show that UV/H2O2 treatment could be suitable as a preliminary stage before a biological treatment
