Angela Beatrice Dewes Moura

Structural characterization and emulsifying properties of polysaccharides of Acacia mearnsii de Wild gum.

Polysaccharides (GNF) from Acacia mearnsii de Wild gum exudates, collected from trees growing in the south of Brazil, were characterized ((13)C and HSQC NMR, GC-MS, colorimetric assays). A commercial gum arabic (GAC) was analyzed similarly and compared with GNF. There were differences, consistent with distinct behavior in tensiometry tests and as emulsion stabilizer. GNF had a higher protein content than GAC, with small differences in the monosaccharide composition, the greater one being the lower uronic acid content of GNF (4%), compared with GAC (17%). GNF had a much broader molecular mass distribution, M(w)/M(n), and a lower M(w). GNF was more efficient in lowering the surface tension of water and saline solutions and was more efficient in emulsifying castor oil droplets. Results were discussed taking into account structural and molecular differences between the studied gums. It was concluded that polysaccharides from A. mearnsii de Wild are candidates as substitutes of currently commercialized arabic gums (Acacia senegal and Acacia seyal) having, depending on their application, improved properties.

Análise termogravimétrica da pirólise da acácia-negra (Acacia mearnsii de Wild.) cultivada no Rio Grande do Sul, Brasil

RESUMO – Este trabalho reporta um estudo experimental que objetivou a investigacao dos efeitos da temperatura, da taxa de aquecimento e do tempo na eficiencia e nos parâmetros cineticos da decomposicao da madeira de acacia-negra (Acacia mearnsii De Wild.) plantada no Rio Grande do Sul. O processo da pirolise da acacianegra foi investigado por analise termogravimetrica (TGA), e os parâmetros cineticos foram obtidos a partir de ensaios dinâmicos e isotermicos. Os ensaios dinâmicos foram conduzidos desde a temperatura ambiente ate 900 C, sob taxas de aquecimento que variaram de 2 a 50 o C.min -1 . Os ensaios isotermicos foram realizados entre 250 e 750 o C, ao aquecer a amostra ate a temperatura desejada e mantendo-se nessa temperatura por 2 h. Os dados cineticos obtidos dinamicamente foram tratados segundo os metodos de Ozawa e Kissinger. Ja os parâmetros cineticos conseguidos isotermicamente foram calculados ao considerar que a reacao de pirolise segue uma cinetica de primeira ordem em todo o intervalo de tempo e temperatura empregados. Os resultados denotaram a aplicabilidade dos metodos adotados, visto que os valores da energia de ativacao do processo de pirolise, alem de se aproximarem entre si, isto e, 170-180 kJ.mol -1 , segundo modelos dinâmicos, e 140 kJ.mol -1 , segundo o metodo isotermico, aproximaram-se tambem dos valores reportados na literatura sobre a pirolise de compostos celulosicos (150-200 kJ.mol -1 ). Os resultados contribuem para a melhor compreensao dos processos de pirolise da biomassa, em especial da acacia-negra, o que pode levar ao melhoramento das atuais praticas de conversao da biomassa em carvao vegetal.

Sintomas respiratórios em trabalhadores de carvoarias nos municípios de Lindolfo Collor, Ivoti e Presidente Lucena, RS

OBJECTIVE To determine the prevalence of respiratory symptoms and smoking, as well as pulmonary function parameters among charcoal production workers in three cities in southern Brazil. METHODS This was an observational study including 67 individuals. Data were obtained by means of interviews and spirometry. RESULTS Of the 67 workers, 50 (75.0%) were male; mean age, 46.52 +/- 13.25 years; mean BMI, 25.7 +/- 3.85 kg/m(2); FEV1, 3.24 +/- 0.82 L (93.2 +/- 16.0% of predicted); FVC, 4.02 +/- 0.92 L (95.5 +/- 14.3% of predicted); and FEV1/FVC, 80.31 +/- 9.82. The most common upper airway symptoms were sneezing and nasal secretion-in 24 workers (35.82%)-whereas the most common lower airway symptom was cough-in 15 (22.38%).Of the 67 workers, 21 (31.34%) were smokers. In comparison with the nonsmokers, the smokers more often presented with cough (OR = 5.00; p = 0.01), nasal obstruction (OR = 3.50; p = 0.03), nasal itching (OR = 8.80; p = 0.01) and wheezing (OR = 10.0; p = 0.03), as well as presenting with lower FEV1 values (2.93 +/- 0.80 vs. 3.38 +/- 0.80 L; p = 0.04). We detected occupational rhinitis in 14 workers (20.85%), asthma in 4 (5.97%) and COPD in 4 (5.97%). CONCLUSIONS Respiratory symptoms and airflow reduction were more common in the smoking workers. Controlling the progression of the pyrolysis did not increase the prevalence of respiratory symptoms in the charcoal production workers studied.

Vegetable Charcoal and Pyroligneous Acid: Technological, Economical and Legal Aspects of its Production and Commerce

The production of vegetable charcoal generates atmospheric emissions, which can be controlled by the instalation of collectors for the condensation of such emissions, forming the pyroligneous acid. The development of collectors for the condensations and characterization of the acid for commerce can contribute with the local sustainable development. This study intends to investigate the technological, economical and legal aspects of the production and commerce of the pyroligneous acid. The chosen method was case study in Presidente Lucena/RS, Brazil, with use of surveys, interviews with producers and responsible government sectors’ representatives. The results indicate that the pyroligneous acid extraction technique is little-known and little used by the producers, that the current market does not absorb the pyroligneous acid offering and the ruling is not relevant.

PYROLIGNEOUS LIQUOR PRODUCED FROM ACACIA MEARNSII DE WILD WOOD UNDER CONTROLLED CONDITIONS AS A RENEWABLE SOURCE OF CHEMICALS

Acacia mearnsii de Wild (black wattle) is one of the most important trees planted in Southern Brazil for tannin extraction and charcoal production. The pyrolysis of the black wattle wood used for obtaining charcoal is performed in brick ovens, with the gas fraction being sent directly into the environment. The present study examines the condensable compounds present in the liquor produced from black wattle wood at different thermal degradation conditions, using gas chromatography coupled with mass spectrometry (GC/MS). Branches of black wattle were thermally degraded at controlled ambient and temperature conditions. Overall, a higher variety of compounds were obtained under atmospheric air pressure than under synthetic air pressure. Most of the tentatively identified compounds, such as carboxylic acids, phenols, aldehydes, and low molecular mass lignin fragments, such as guayacol, syringol, and eugenol, were products of lignin thermoconversion. Substituted aromatic compounds, such as vanillin, ethyl vanillin, and 2-methoxy-4-propeny-phenol, were also identified. At temperatures above 200 oC, furan, 2-acetylfuran, methyl-2-furoate, and furfural, amongst others, were identified as polysaccharide derivatives from cellulose and hemicellulose depolymerization. This study evidences the need for adequate management of the condensable by-products of charcoal production, both for economic reasons and for controlling their potential environmental impact.

Dejeto suíno e extrato pirolenhoso – influência na retenção/lixiviação de metais no solo

Os dejetos liquidos de suinos (DLS) e o extrato pirolenhoso (EP) geralmente sao utilizados como fertilizantes em areas agricolas. Quando dispostos na natureza de forma inadequada, eles podem causar impactos ambientais negativos, tanto para o solo, quanto para os lencois freaticos. Este estudo propoe pesquisar o efeito da incorporacao do extrato pirolenhoso no solo, juntamente com DLS, na mobilidade dos metais Cu e Zn e contaminantes tipicamente presentes nos DLS. Os experimentos foram conduzidos em colunas de solo com adicao de EP e DLS, em concentracoes determinadas, para verificar a lixiviacao dos metais. As colunas foram submetidas a regas regulares. Os percolados foram analisados por espectrometria de absorcao atomica para a quantificacao dos metais estudados. Os resultados mostraram o perfil de lixiviacao de Cu e Zn. Pode-se verificar que a combinacao da adicao do DLS e do EP ao solo diminui a lixiviacao dos metais analisados.