Browsing by Author "Lescano, Maia Raquel"

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    Microparticles based on ionic and organosolv lignins for the controlled release of atrazine
    (Journal of Hazaourdos Materials, 2018-07-02) Taverna, María E.; Busatto, Carlos Alberto; Lescano, Maia Raquel; Nicolau, Verónica V.; Zalazar, Cristina; Meira, Gregorio; Estenoz, Diana
    Lignins are natural polymers of the lignocellulosic biomass. Nowadays, there is a growing interest in developing value-added products based on lignins due to their renewability, low cost and abundance. In this work, lignin microspheres from organosolv and ionic isolation processes were prepared for the controlled release of atrazine. Microspheres were prepared by the solvent extraction/evaporation technique. The controlled release of atrazine from organosolv and ionic lignins microparticles was studied in water. Mobility experiments were performed in an agricultural soil from Argentina. The results showed that microparticles prepared using dichloromethane as the dispersed phase were spherical, while lignins dispersed in ethyl acetate produce irregular microparticles. Organosolv lignin microparticles presented higher encapsulation efficiency for all herbicide loads. About 98% and 95% of atrazine was released in 24 and 48h approximately from organosolv and ionic lignin microparticles, respectively. The release profiles of atrazine from both lignin microparticles were not affected by the herbicide load. Atrazine mobility experiments in soil showed that about 80% of free atrazine was leached in 37 days, while 65.0% and 59.7% of the herbicide was leached from ionic and organosolv lignin microparticles, respectively. Thus, atrazine-loaded microparticles could reduce leaching compared to a commercial formulation of free atrazine.
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    Morphology modulation of silica mesoporous nano- and microparticles for atrazine - controlled release
    (2022-06-09) Fookes, Federico A.; Busatto, Carlos Alberto; Taverna, María E.; Casis, Natalia; Lescano, Maia Raquel; Estenoz, Diana
    Atrazine is a moderately toxic triazine, used as a selective pre- and post-emergence herbicide. After application, it remains in the environment due to its low biodegradability causing severe environmental effects. Several controlled release systems have been proposed in order to minimize the negative impact of the herbicide on the environment. In particular, mesoporous silica nanoparticles have shown great potential in the agricultural area due to their controlled size and porosity, high surface area and non-toxicity. In this work, silica nano- and microparticles were synthesized and evaluated as atrazine delivery systems. The morphology and size distribution of the particles were characterized using dynamic light scattering (DLS) and scanning electron microscopy (SEM). The release profiles were studied by in vitro assays in water. In addition, phytotoxicity tests were performed using Lactuca sativa seeds. The mesoporous nano- and microparticles exhibited sustained release for at least 24 h and reduced phytotoxicity compared to free atrazine.
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    Preparación y caracterización de nano- y micropartículas de sílice para la liberación controlada de atrazina
    (AJEA- Actas de Jornadas y Eventos Académicos de UTN, 2021-11-29) Fookes, Federico A.; Busatto, Carlos Alberto; Taverna, María E.; Lescano, Maia Raquel; Estenoz, Diana
    La atrazina (2-cloro-4-etilamina-6-isopropilamina-s-triazina) es una triazina moderadamente tóxica, utilizada como herbicida selectivo de pre y post-emergencia. Después de su aplicación permanece en el medio ambiente debido a su baja biodegradabilidad y larga vida media en agua (entre 30 y 100 días). A fin de reducir el impacto ambiental de estos herbicidas se han empleado matrices orgánicas e inorgánicas para el desarrollo de sistemas de liberación controlada. Dentro de las matrices inorgánicas, se han evaluado las nanopartículas de sílice mesoporosas debido a su porosidad y elevada área superficial. En este trabajo se prepararon y caracterizaron nano- y micropartículas de sílice para la encapsulación de atrazina. Se evaluó el perfil de liberación mediante ensayos in vitro en agua y, además, se realizaron ensayos de fitoxicidad en semillas de lechuga. Se observó que las nanopartículas mesoporosas presentan una liberación sostenida por al menos 24 h y una fitotoxicidad reducida
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    Preparation and Characterization of Lignin Microparticles-in-Alginate Beads for Atrazine Controlled Release
    (2019-09-21) Busatto, Carlos Alberto; Taverna, María E.; Lescano, Maia Raquel; Zalazar, Cristina; Estenoz, Diana
    The use of lignin as polymeric matrices for controlled release systems in agriculture is a promising alternative for its reval-orization. In this work, diferent atrazine delivery systems were studied. Lignin derived from ionic isolation was used for the preparation of atrazine-loaded microparticles by the solvent extraction/evaporation and microfuidic techniques. Micropar-ticles were also encapsulated in sodium alginate beads. Lignin microparticles prepared by microfuidics presented a larger particle size, higher encapsulation efciency and a narrow size distribution. The in vitro release of atrazine was evaluated in water. Atrazine release from microparticles prepared by the solvent extraction/evaporation technique showed a signifcant burst release, and this efect was reduced by incorporating microparticles within alginate beads. In addition, the phytotoxicity of the systems was evaluated employing Lactuca sativa seeds. The phytotoxicity results showed that lignin-based formula- tions are safe according to the parameters evaluated, in contrast with commercial atrazine that resulted phytotoxic.