Low tungsten content of nanostructured material supported on carbon for the degradation of phenol

A comparative study using different mass proportions of WO3/C (1%, 5%, 10% and 15%) for H2O2 electrogeneration and subsequent phenol degradation was performed. To include the influence of the carbon substrate and the preparation methods, all synthesis parameters were evaluated. The WO3/C materials were prepared by a modified polymeric precursor method (PPM) and the sol-gel method (SGM) on Vulcan XC 72R and Printex L6 carbon supports, verifying the most efficient metal/carbon proportion. The materials were physically characterized by X-ray diffraction (XRD) and by X-ray photoelectron spectroscopy (XPS) techniques. The XRD and the XPS techniques identified just one phase containing WO3 and elevated oxygen concentration on carbon with the presence of WO3. The oxygen reduction reaction (ORR), studied by the rotating ring-disk electrode technique, showed that WO3/C material with the lowest tungsten content (1% WO3/C), supported on Vulcan XC 72R and prepared by SGM, was the most promising electrocatalyst for H2O2 electrogeneration. This material was then analyzed using a gas diffusion electrode (GDE) and 585mgL-1 of H2O2 was produced in acid media. This GDE was employed as a working electrode in an electrochemical cell to promote phenol degradation by an advanced oxidative process. The most efficient method applied was the photo-electro-Fenton; this method allowed for 65% degradation and 11% mineralization of phenol during a 2-h period. Following 12h of exhaustive electrolysis using the photo-electro-Fenton method, the total degradation of phenol was observed after 4h and the mineralization of phenol approached 75% after 12h. © 2013 Elsevier B.V.

Phenolic composition of the berry parts of hybrid grape cultivar BRS Violeta (BRS Rubea×IAC 1398-21) using HPLC-DAD-ESI-MS/MS

The grape is considered a major source of phenolic compounds when compared to other fruits and vegetables, however, there are many cultivars with distinct characteristics directly linked to phenolic profile. Thus, the present study aimed to identify and quantify, for the first time and in detail, the phenolic compounds present in the skin, flesh and seeds of BRS Violeta grape berry using combination of SPE methodologies and analytical HPLC-DAD-ESI-MS/MS. The study was extended to the different berry parts and the most important grape and wine phenolic families, and has revealed interesting features. Violeta grape has a very thick skin (46% of grape weight) that accumulated the most of grape phenolic compounds: great amount of anthocyanins (3930. mg/kg, as malvidin 3,5-diglucoside), together with also important amounts of flavonols (150. mg/kg, as quercetin 3-glucoside), hydroxycinnamic acid derivatives (HCAD; 120. mg/kg, as caftaric acid), and proanthocyanidins (670. mg/kg, as (+)-catechin); in contrast, it seems to be a low resveratrol producer. Violeta grape seeds accounted for similar proportions of low molecular weight flavan-3-ols (mainly monomers; 345. mg/kg, as (+)-catechin) and proanthocyanidins (480. mg/kg, as (+)-catechin). Violeta grape is a teinturier cultivar, but it only contained traces of anthocyanins and low amounts of all the other phenolic types in its red-colored flesh. The anthocyanin composition of Violeta grape was dominated by anthocyanidin 3,5-diglucosides (90%). Within flavonols, myricetin-type predominated and kaempferol-type was missing. In addition to expected hydroxycinnamoyl-tartaric acids, several isomeric esters of caffeic and p-coumaric acids with hexoses were tentatively identified, accounting for relevant proportions within the pool of HCAD. Although pending of further confirmation over successive vintages, the aforementioned results suggest that BRS Violeta grape cultivar could be considered an interesting candidate for the elaboration of highly colored and antioxidant-rich grape juices and wines. © 2013 Elsevier Ltd.

Estudo da atividade antioxidante de frutas tropicais exóticas sobre espécies reativas de oxigênio de importância biológica em ensaios modelos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização bioquímica e centesimal das espécies Astrocaryum vulgare Mart. (tucumã) e Endopleura uchi (Huber) Cuatrec. (uxi) nativas da região Amazônica

Pós-graduação em Biotecnologia - IQ

Produção e utilização de farinha de mandioca comum enriquecida com adição das próprias folhas desidratadas para consumo alimentar

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Estudo químico e atividade mutagênica e antiradicalar e Paepalanthus chiquitensis Herzog (ERIOCAULACEAE)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Marcha de absorção de macronutrientes e acúmulo de fenólicos totais em [(Baccharis Trimera (Less.) DC.] var. CPQBA-1, sob diferentes podas no plantio

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Qualidade de carambolas submetidas a diferentes tratamentos pós-colheita

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Modo de cultivo e sanitização na pós-colheita de repolho híbrido 'Fuyutoyo'

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inibidores de etileno na pós-colheita de Lisianthus

Pós-graduação em Agronomia (Horticultura) - FCA

Desempenho de reatores anaeróbios de fluxo ascendente com manta de lodo (UASB) em dois estágios tratando águas residuárias do beneficiamento de café por via úmida

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desempenho de reatores anaeróbios horizontais com manta de lodo e de leito fixo, em série, tratando águas residuárias do beneficiamento do café por via úmida

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudos químicos e anatômicos de cascas de clones de Eucalyptus

The barks generated from the wood processing industries are wastes generated in significant quantities, becoming interesting to have basic studies of their anatomical and chemical properties in order to make better use of this material. This study aimed to carry out anatomical studies, chemical and tannins from the barks of commercial clones of Eucalyptus. For this, permanent histological slides for anatomical characterization and percentage of cellular elements were prepared; and cellular elements were dissociated for biometry of the elements. The analyses were related to chemical extractives, ash, lignin, suberin, sugars, phenols, tannins, flavonoids and antioxidant activity of the extracts. The tannins were extracted in pure water and with water mixed with sodium sulfite, and were subsequently evaluated the properties by FT-IR. It was verified by the anatomical characterization and chemical quantification, the similarity between the clones. Regarding the biometrics of cellular elements, statistically significant differences were not observed for the following parameters: length and diameter of sieve tube, axial parenchyma diameter, and rays hight. The yield of condensed tannins and Stiasny index for studied clones are low, showing the infeasibility of using bark for the extraction of tannins to produce adhesives, however tannins and other bioactive phenolic compounds can be used in the pharmaceutical and cosmetics sectors due to its antioxidant potential. The spectrum of tannins is the same as the one found the literature. Due to the high yield of verified sugar, (around 46,68%) sugars are potencial products, with a high yield of glucose , it is interesting for application in biorefinery.

Estudo de pré-tratamentos de bagaço de cana para produção de etanol celulósico por hidrólise enzimática

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise dos compostos flavorizantes da cana-de-açúcar e otimização da aplicação de extratos ricos em β-glicosidases para liberação de aroma na produção de aguardente de cana

Pós-graduação em Química - IBILCE