Léa Elias Mendes Carneiro Zaidan

Heterogeneous photocatalytic degradation of phenol and derivatives by (BiPO4/H2O2/UV and TiO2/H2O2/UV) and the evaluation of plant seed toxicity tests

We examined the photocatalytic degradation of phenol from laboratory samples under UV radiation by using BiPO4/H2O2 and TiO2/H2O2 advanced oxidation systems. Both catalysts prepared were characterized by scanning electron microscopy, Fourier transform infrared and X-ray diffraction. Surface area tests showed about 3.46 and 31.33m2·g−1, respectively, for BiPO4 and TiO2. A central composite design was developed with the following variables--catalyst concentration, time and concentration of hydrogen peroxide--to optimize the degradation process. Removal rates of 99.99% for phenol degradation using BiPO4 and TiO2 were obtained, respectively. For mineralization of organic carbon were obtained 95,56% when using BiPO4 and 63,40% for TiO2, respectively. The lumped kinetic model represented satisfactorily the degradation of phenol process, using BiPO4/H2O2/UV (R2=0.9977) and TiO2/H2O2/UV (R2=0.9701) treatments. The toxicity tests using different seed species showed the benefits of the proposed advanced oxidation process when applied to waste waters containing these pollutants.

EVALUATION OF EFFICIENCY OF ADVANCED OXIDATIVE PROCESS IN DEGRADATION OF 2-4 DICHLOROPHENOL EMPLOYING UV-C RADIATION REATOR

The study accomplished to analyze, identify and quantify 2,4-dichlorophenol employing high efficiency chromatography with a previously validated analytical methodology. The validation was made by using some analytical parameters: linearity, precision, accuracy, quantification limit (LOQ) and detection limit (LOD). The analytical curve was linear for the studied range of concentration (10 up to 100 mg.L -1 ) presenting a linear regression coefficient (R 2 ) above 0,99. Regarding the methodology accuracy, a repeatability analysis was performed by observing a coefficient of variance (CV) below 20% for each of the concentrations used. The LOD and LOQ were adequate for the analyzed compound, showing the values of 1.42 mg.L -1 and 4.30 mg.L -1 , respectively. The tests to verify the accuracy, by the recovery method provided values above 79%, thus resulting in specific, sensitive, precise, linear and accurate methodology in the studied concentration range. In the advanced oxidative process UV/H 2 O 2 , the compound was degraded to 88.04% under the following experimental conditions: [H 2 O 2 ] = 1016.0 mg∙L -1 in 120 minutes. Therefore, it can be affirmed that the treatment employed can be used as an alternative for industrial effluent treatment with phenolic compounds.

Otimização do processo de remoção do corante preto de remazol B por uso de biomassa mista de Aspergillus niger van Tieghem, 1867 (Ascomycota: Trichocomaceae) e Pennisetum purpureum Schumach., 1827 (Poales: Poaceae)

Otimizacao do processo de remocao do corante preto de remazol B por uso de biomassa mista de Aspergillus niger van Tieghem, 1867 (Ascomycota: Trichocomaceae) e Pennisetum purpureum Schumach., 1827 (Poales: Poaceae)

Degradação do contaminante emergente paracetamol empregando processos oxidativos avançados

Uma classe de poluentes tem sido investigada por pesquisadores de todo o mundo, estes sao os contaminantes emergentes, que sao considerados persistente e refratario. Estes compostos estao presentes em diferentes matrizes ambientais em baixas concentracoes que requerem tratamentos alternativos de polimento capazes de promover a degradacao destes poluentes, uma vez que os tratamentos convencionais nao sao capazes de remove-los. Este estudo avaliou a degradacao do paracetamol utilizando processos oxidativos avancados (acao UV/H 2 O 2 e foto-Fenton). Os resultados mostraram que o processo acao UV / H 2 O 2 foi mais eficiente conseguindo promover a degradacao de 99% do paracetamol, o que e corroborado pela estatistica que mostraram que as experiencias isentas da adicao de ferro (UV / H 2 O 2 ) foram os mais eficientes na degradacao do paracetamol em solucao aquosa solucao. A metodologia para a identificacao atraves de cromatografia foi validado de acordo exigencia das agencias existentes (INMETRO e ANVISA), assegurando a confiabilidade dos resultados.