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Diferentes materiales adsorbentes fueron preparados a partir de la cascarilla de arroz (un residuo lignocelulósico agroindustrial), para la remoción de cromo presente en las aguas resultantes de la curtición, debido a su alta toxicidad para la salud humana y a nivel ambiental. La cascarilla de arroz se evaluó como ceniza y carbón activado con acido fosfórico e hidróxido de sodio como agentes activantes. La parte experimental consistió en la calcinación de la cascarilla de arroz, activación química, caracterización, pruebas de adsorción y absorción atómica; obteniendo mejores resultados el adsorbente activado con hidróxido de sodio. Para la activación de la cascarilla de arroz con NaOH se requirió una serie de experimentos para determinar las mejores condiciones de operación en el proceso de obtenci��n del carbón activado. Se obtuvo una mayor remoción en el carbón que se activo a una temperatura de 600°C, un tiempo de activación de 30 minutos y una concentración de la solución de 1% p/p; la remoción de cromo fue del 72,8% comparado con la cascarilla de arroz activada con H3PO4 que fue del 54,5% y la ceniza de cascarilla de arroz 49,2%.Diferentes materiais adsorventes fórum preparados a partir da casca de arroz, um resíduo lignocelulósico agroindustrial, para a remoção de cromo das águas resultantes da curtição, devido a sua alta toxicidade na saúde e ao nível ambiental. A casca de arroz, a qual se avalia como cinza e carvão ativado com acido fosfórico e hidróxido de sódio como agentes ativadores. A parte experimental consta de calcinação da casca de arroz, ativação química, caracterização, testes de adsorção e absorção atômica; obtendo os melhores resultados o adsorvente ativado com hidróxido de sódio. A ativação da casca de arroz com NaOH se precisaram uma série de experimentos para determinar as melhores condições de operação no processo de obtenção do carvão ativado. Obteve-se uma maior remoção no carvão que se ativo a uma temperatura de 600°C, um tempo de ativação de 30 minutos e uma concentração da solução de 1% p/p; a remoção foi do 72,8% comparado com a casca de arroz ativada com H3PO4 que foi do 54,5% e a cinza de casca de arroz 49,2%.Several adsorbent materials were prepared from rice husk, a lignocellulosic waste from agro-industry, for the removal of chromium present in the effluents of the tanning, due to its high toxicity in the health and to environmental level. The rice husk was evaluated as ash and activated coal with phosphoric acid or hydroxide of sodium as activating agents. The experimental part consisted of calcination of the rice husk, chemical activation, characterization, tests of adsorption and tests of atomic absorption; obtaining better results the adsorbent activated with hydroxide of sodium. The activation of the rice husk with NaOH required a series of experiments to determine the best conditions of operation in the process of obtaining of the activated coal. A major removal was obtained in the coal that was activated at 600°C 30 minutes of activation time and 1% p/p of solution concentration; the removal was of the 72,8 % compared with the rice husk ash activated with H3PO4 that was of the 54,5% and the rice husk ash 49,2%.

Pectin is a polysaccharide contained in the cell wall of most vegetables and fruits, with beneficial health properties and widely used in the food industry. The aim of the study was to evaluate the effect of pre-treatment with ultrasound (US) in extracting pectin contained in the albedo of passion fruit, the samples were exposed to 40 KHz at a temperature of 30, 45 and 60°C for 10, 20 and 30 minutes. The samples were extracted by acid hydrolysis ratio 1: 3 (% w/%v) on heating to 80°C for 30 minutes shaking at 700 rpm, we proceeded to filter and precipitate by adding 96% ethanol in a ratio (1:1) (%v/%v). Determining that the samples treated at 40 KHz/45°C/20 min, obtained a 40% increase in the extraction yield of pectin compared to control samples; probably due to the decrease in pH and the effect of cavitation where the particles are accelerated to vibrate and ultrasonic action, causing a macro turbulence and interparticle collision biomass accelerating diffusion; pectin extract achieving high quality and usable for the production of products of interest. [ABSTRACT FROM AUTHOR]

Diferentes materiales adsorbentes fueron preparados a partir de la cascarilla de arroz (un residuo lignocelulósico agroindustrial), para la remoción de cromo presente en las aguas resultantes de la curtición, debido a su alta toxicidad para la salud humana y a nivel ambiental. La cascarilla de arroz se evaluó como ceniza y carbón activado con acido fosfórico e hidróxido de sodio como agentes activantes. La parte experimental consistió en la calcinación de la cascarilla de arroz, activación química, caracterización, pruebas de adsorción y absorción atómica; obteniendo mejores resultados el adsorbente activado con hidróxido de sodio. Para la activación de la cascarilla de arroz con NaOH se requirió una serie de experimentos para determinar las mejores condiciones de operación en el proceso de obtención del carbón activado. Se obtuvo una mayor remoción en el carbón que se activo a una temperatura de 600°C, un tiempo de activación de 30 minutos y una concentración de la solución de 1% p/p; la remoción de cromo fue del 72,8% comparado con la cascarilla de arroz activada con H3PO4 que fue del 54,5% y la ceniza de cascarilla de arroz 49,2%.

Several adsorbent materials were prepared from rice husk, a lignocellulosic waste from agro-industry, for the removal of chromium present in the effluents of the tanning, due to its high toxicity in the health and to environmental level. The rice husk was evaluated as ash and activated coal with phosphoric acid or hydroxide of sodium as activating agents. The experimental part consisted of calcination of the rice husk, chemical activation, characterization, tests of adsorption and tests of atomic absorption; obtaining better results the adsorbent activated with hydroxide of sodium. The activation of the rice husk with NaOH required a series of experiments to determine the best conditions of operation in the process of obtaining of the activated coal. A major removal was obtained in the coal that was activated at 600°C 30 minutes of activation time and 1% p/p of solution concentration; the removal was of the 72,8 % compared with the rice husk ash activated with H3PO4 that was of the 54,5% and the rice husk ash 49,2%. [ABSTRACT FROM AUTHOR]