Identificação e destruição fotocatalitica em fase gasosa de compostos causadores de odor em efluentes

AUTOR(ES)

Maria Cristina Canela

DATA DE PUBLICAÇÃO

1999

RESUMO

Malodorous compounds have been a nuisance in any neighborhood under the influence of emission sources. The odors are caused mainly by sulfurous and nitrogen compounds, ketones, aldehydes and acids, which show an extremely low odor threshold. In this work, malodorous compounds were identified using pre-concentration onto adsorbent column (Tenax®), liquid-Iiquid extraction, and sensory analysis in three different wastewater samples: sewage (ESD), raw wastewater of a jelly factory before (GeI1) and after the physico-chemical treatment (GeI2). For the ESD some sulfur and nitrogen containing compounds, hydrocarbons, substituted benzenes, beside components of essential oils and aldehydes were identified. These compounds were considered as the main responsible for the septic and grass/earth odor described by the panel. For Gel1 and Gel2, compounds such as dimethyl disulfide and dimethyl trisulfide were present in high concentration. Phenolic compounds (phenol and p-cresol) and indol, were also detected. H2S was detected in all samples and NH3 was detected in both Gel1 and Gel2. Photocatalytic destruction of volatile compounds such as H2S, sulfur and nitrogen-containing compounds was achieved using TiO2/UV-VIS, with rates of degradation around 100%. The main products detected in the degradation of sulfur-containing compounds were SO4 ions and CO2, whereas for nitrogen-containing compounds, NH4 and NO3 ions, and CO2 were the major products. Studies about photodestruction of malodorous compounds in the ESD, Gel1 and Gel2 samples showed that the main compounds were destructed, which was observed by both sensory analysis and GC through an abatement in the intensity of odor and in the chromatograms peak areas. Photocatalysis seems to be a promising technology in the degradation of pollutants in the gas phase, mainly at low concentrations.

ASSUNTO(S)

avaliação sensorial fotocatalise

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