RESUMO
The aim of this work has been to study the viability of ozone and/or UV in the treatment of cardboard industry effluents. Several model compounds have been chosen for the experiments: guaicol, eugenol, glucose, acetate and butyrate. Significant differences in the ozonisation rates are observed between phenolic products coming from lignin (eugenol and guaiacol) and aliphatic compounds. Reactions fit in all cases a pseudo-first order kinetics and are influenced by the pH of the solution. Real effluents have also been tested, and the COD decrease has been found to depend on the fatty acids/phenols ratio. Finally, respirometric studies have shown an increase in the BODst in effluents subjected to a mild oxidation, while under stronger conditions a BODst decrease is observed.
Assuntos
Ozônio/química , Papel , Raios Ultravioleta , Poluentes Químicos da Água , Bactérias Aeróbias/metabolismo , Reatores Biológicos , Butiratos/química , Butiratos/efeitos da radiação , Eugenol/química , Eugenol/efeitos da radiação , Glucose/química , Glucose/efeitos da radiação , Guaiacol/química , Guaiacol/efeitos da radiação , Resíduos Industriais , Oxidantes Fotoquímicos/química , Oxirredução , Oxigênio/análise , Acetato de Sódio/química , Acetato de Sódio/efeitos da radiação , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/efeitos da radiaçãoRESUMO
This study examined the effects of storage conditions such as time course, temperature, fluorescent light, and darkness on the components and antibacterial activity of formalin guaiacol (FG) used in endodontic treatment. We measured the quantities of formaldehyde and guaiacol in FG and antibacterial activities against Staphylococcus aureus, Porphyromonas gingivalis, and Porphyromonas endodontalis. The components and antibacterial activity of FG in the brown or transparent tightly sealed containers were not affected by temperature or fluorescent light throughout the 4 week test. However, in the loosely sealed containers, formaldehyde and guaiacol in FG sample decreased remarkably within one week, not only in a temperature- and time-dependent manner, but also under fluorescent light at 20 degrees C. Furthermore, the antibacterial activities in the FG sample were significantly attenuated in parallel with the decrease in formaldehyde levels. Fluorescent light caused color changes and crystallization of FG samples in the transparent containers. These results suggest that it is important to replace fresh FG every 5 to 7 days for endodontic treatment and that, in the dental office, it is advisable to store fresh FG in tightly sealed containers every 2 weeks to maintain its efficacy.
