Tratamiento de aguas residuales provenientes de la fase de teñido de la curtiembre mediante un sistema físico-químico basado en la oxidación avanzada con la ayuda del semiconductor TiO2 en presencia de luz UV

摘要

In Ecuador one of the industries that stand out is the leather industry, this industry is especially concentrated in the province of Tungurahua. One of the major problems the industry is facing is the large amount of wastes they produced, being the most important the water pollution. These effluents contain debris such as hair, skin, blood, dung, rock salt, chromium salts, sulphides, dirt stuck to the skin, proteins, fats, lime, ammonia nitrogen, surfactants and dyes. Furthermore the effluents generated during the tanning process contain high concentrations of toxic chemicals such as chromium and sulphide, as well as suspended solids and organic matter. For this study we concentrated on the phase of dyeing for which acids and dyes are used. The main problem of the effluent generated during the dyeing process is the dye concentrations. The azoic dyes that are used are non-toxic but their degradation products such as aromatic amines can be carcinogenic and mutagenic being a great danger to human health. The objective of this study is to treat the dye material found in the wastewater from the dyeing phase of the rather production. Therefore, a physic-chemical system based on the advanced oxidation with the aid of a semiconductor in the presence of UV light was performed. To reach this objective the study consisted of different analyzes and experiments at laboratory scale. First, it was performed a study of the behavior of the dye Trupocor T Extra, which is used for dyeing, with the semiconductor TiO2 by adsorption isotherms. Second, laboratory scale experiments were performed with dye solutions at different concentrations, these experiments were conducted in two ways: batch experiments with the semiconductor in suspension in the presence of UV light, and experiments using a Plug Flow Reactor with the semiconductor fixed on a bed of sand in the presence and absence of UV. For the next phase of the study, wastewater from the dyeing processes was characterized by measuring different parameters. Finally, for the treatment of wastewater a PFR reactor was used with the semiconductor fixed on sand particles in the presence and absence of UV light.Batch experiments show a dye removal of 34% for a concentration of 50mg/L and for a concentration of 10mg/L a removal of 83%. Experiments in the PFR reactor show an average removal of 94.25 % in the absence of UV light and of 95.35 % in the presence of UV light. Experiments for the removal of dye from the wastewater show a removal to 89.75% in the presence of UV light and in the absence of UV light an averaged removed of 78 %.