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Uso de macroalgas e variáveis físicas, químicas e biológicas para a avaliação da qualidade da água do Rio do Monjolinho, São Carlos, Estado de São Paulo
(Universidade Federal de São Carlos, 2002-04-15) Peres, Ana Claudia; Senna, Pedro Américo Cabral; https://lattes.cnpq.br/2513500213269643
A fluvial ecosystem has a big interaction surface with the terrestrial ecosystems. The river interact with the terrestrial ecosystem, in drains, in an equilibrated and functional unit. Besides being is a low tension system, that is overloaded and that exports part of its materials, it keeps a quick cycle. Macroalgae are benthic organisms that produce a mature stalk, that has a discreet structure, however recognized by naked eye. Those algae have been used for river monitoring, in Europe particularly, as biological indicators and they are better than the physical and chemical variables, that reflects only the water conditions in the collecting moment, whereas the biological indicators reproduce medium-long term aspects of living organisms. This study has as principal aiming, was to establish a relationship between the macroalgae species found and the ambiental variables at the Monjolinho River, tracing a water quality profile of this river. The study was performed in 6 months (May to October, 1998 dry season) in six sampling stations distributed along all the river extension. During six months sampling were performed in a six stretch of 10m along to the river course. Water was collected for nutrient and suspended matter analyses and measurements of variables as, water temperature, conductivity, pH, turbidity and dissolved oxygen. Macoralgae were samples qualitatively and quantitatively. A total of 16 sampling macroalgae species present, among which Vaucheria geminata, Schysomeris leibleinii, Geithlerinema amphybium and Stigeoclonium helveticum had a wide distribution. In relation to the ambiental variables, the station was found to have the lowest nutrient concentration and highest OD, whereas the station 3 had the highest nutrient concentration and lowest OD concentrations. The sampling stations were classified, according to the values of BOD, saturation oxygen deficit, NH4, and OM as: station 1 Oligossaprobic (health water zone, not affected by the pollution ), station 2 and 6 â-mesossaprobic (zone of lightly weak pollution), station, 4 and 5 á-messoproibic (polluted zone or strongly polluted) and station 3 polissaprobic (extremely polluted zone or intense bacterial decomposition).
Obtenção e caracterização eletroquímica do compósito polipirrol
(Universidade Federal de São Carlos, 2002-04-15) Bello, Maria Elvira do Rêgo Barros; Souza, Ernesto Chaves Pereira de; https://lattes.cnpq.br/1505400360366643
This study was carried out to investigate the electrochemical preparation of a composite polypyrrole / cobalt, as well as your characterization physical-chemistry. The composite was electropolymerized on a platinum substrate in aqueous solution with lithium perchlorate. It was characterized electrochemically with cyclic voltammetry. A voltammetric behavior quite differentiated between the pure polypyrrole and the composite it was observed, above all, for the pronounced cathodic peak that appeared in the voltammogram of the composite, which was attributed to the metallic deposition. The interesting in this case was that the cathodic peak appeared in a more positive potential in the composite than when verified on pure platinum. Besides, it was observed although in presence of the cobalt the redox processes in the polymeric suffered a potential displacement. Such results suggested the presence of an interaction between the metallic cobalt and the polymeric phase, possibly a complexation between the cobalt and the polypyrrole. A morphological analysis of the film was made by scanning electronic microscopy, having observed a more regular surface and with smaller nodules for the material of the composite. The X-ray difractometry of the films it was also done, but it didn't take to conclusive results. A chemometrics study was accomplished through 22 factorial design involving the synthesis variables and the voltammetric analysis variables of the composite, while optimization procedures, using the response surface methodology, was accomplished with the intention of increasing the intercalation of the cobalt in the polymeric phase. As a measure of the intercalation, it was taken the parameter current density of cathodic peak of the process regarding the cobalt. The results showed an increase of 73.7% in this current density of cathodic peak for the film synthesized in the optimized condition, in comparison with the largest value found before the optimization.