Toxinas de cianobactérias têm se tornado um grave problema na produção segura de água para consumo humano e animal. Técnicas convencionais de tratamento falham em atingir padrões de potabilidade. O ferrato(VI) de potássio, um composto oxidante e coagulante, mostra potencialidade no tratamento de águas contaminadas. Neste trabalho, são apresentados resultados da oxidação pelo ferrato(VI) de uma toxina gerada por cianobactérias, a microcistina-LR. Ensaios de cinética de oxidação e de teste de jarros mostram um valor médio de 0,012 min-1 para a constante de taxa de reação de pseudoprimeira ordem, para concentrações de MC-LR de 100 a 200 µg.L-1 na água bruta. Dosagens de 1,6 a 5,0 mg.L-1 de ferrato(VI) sugerem o atendimento ao padrão de potabilidade para microcistinas, mostrando que o oxidante poderá ser empregado como coadjuvante no tratamento de água.

Algae toxins are becoming a severe problem in the water treatment industry, especially for human and animal consumption. Traditional treatment processes have failed in complying with water supply standards. Potassium ferrate(VI) is a powerful oxidant, disinfectant and, also, a coagulant. In this paper, the results of microcystin-LR oxidation by ferrate(VI) ion are presented. Kinetic and jar tests showed a average value of 0,012 min-1 for the pseudo first order reaction rate constant, for 100 and 200 µg.L-1 concentration of MC-LR. Ferrate(VI) dosages between 1.6 and 5.0 mg.L-1 suggest that water supply standards for MC-LR can be reached, which means that the oxidant may be employed as coadjuvant in water treatment.

The optimization of ferrate(VI) ion generation has been studied due to its favorable characteristics for application in several fields, including environmental quality control. The paper presents the best conditions for electrolytic generation of ferrate(VI) in alkaline media. An appropriate electrolyte was NaOH, 10 mol/L. Circulation of the electrolyte solution was important to avoid acidification close to the anode surface. An anode pre-cleaning with 10% HCl was more efficient than a cathodic pre-polarization. Among the distinct anode materials tested, pig iron showed the best performance, allowing up to 20 g/L of Na2FeO4, in 10 mol/L NaOH solution to be obtained, after 7 h of reactor operation, which is a concentration higher than those found in literature for alternative processes.

We evaluate the orientation of microstructural elements of isotatic polypropylene (i-PP) before and after deformation using computerized "Quantikov" software analysis of Scanning Electron Microscopy (SEM) images. We observed that before deformation through uniaxial compression, the polymeric material doesn’t exhibit any significant orientation. After deformation at 1349 MPa the material clearly showed preferential orientation that was attested by the orientation axis seen between two petals of the rose of the number of intercepts. This effect was more pronounced after deformation at 2699 MPa.