Solubilization of herbicides by single and mixed commercial surfactants

Póster presentado al citado congreso, en la sesión W12.01-P.: Pesticides in soil, fate and effects on environment - In collaboration with GRIFA. Celebrado del 2-6, julio, 2012, en Fiera del Levante, Bari, Italia.Peer reviewe

Solubilization of herbicides by single and mixed commercial surfactants

8 páginas.-- 3 figuras.-- 6 tablas.-- 43 referencias.-- Appendix A. Supplementary data Solubilization in single and equimolar mixed surfactants of MST (Fig. S1), FL (Fig. S2) and MTZ (Fig. S3). Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.scitotenv.2015.08.008The solubilization capabilities of micellar solutions of three single surfactants, two alcohol alkoxylates B048 and B266, and the tallow alkyl ethoxylated amine ET15, and their equimolar mixed solutions toward the herbicides flurtamone (FL), metribuzin (MTZ) and mesotrione (MST) were investigated. The solubilization capacity was quantified in terms of the molar solubilization ratio (MSR), critical micellar concentration (CMC), micelle-water partition coefficient (Kmc), binding constant (K1), number of aggregation (Nagg) and Stern-Volmer constant (Ksv). The herbicides were greatly solubilized into different loci of the micelles: FL within the inner hydrophobic core, MST at the micelle/water interface and MTZ in the palisade region. Equimolar binary surfactant mixtures did not improve the solubilization of herbicides over those of single components, with the exception of MTZ by the B266/ET15 system which enhanced solubilization by 10-20%. This enhanced solubilization of MTZ was due to an increased number of micelles that arise from both the intermediate Nagg relative to that of the single surfactants and the lower CMC. The use of Ksv values was a better predictor of the solubilization of polar molecules within binary mixtures of these surfactants than the interaction parameter βM from regular solution theory (RST). The results herein suggest that the use of mixed surfactant systems for the solubilization of polar molecules in environmental remediation technologies may be very limited in scope, without clear advantages over the use of single surfactant systems. © 2015 Elsevier B.V.This research was supported by the MEC project CTM2009-07425 and the Junta de Andalucía Project P09-RNM4581. Both projects received funding from the European Social Fund. It was also supported by the ENPI-CBCMED Project Nanowat (ref. I-B/2.1/049). M.C. Galán-Jiménez acknowledges a research contract from Junta de Andalucía in the frame of project P09-RNM4581. The authors are grateful to Campi y Jove S.A (Barcelona, Spain) for the supply of the commercial surfactants.Peer reviewe

Aproximación metodológica para el desarrollo de formulaciones de liberación lenta de herbicidas usando complejos sepiolita-surfactantes

3 páginas.-- 3 figuras.-- 1 tabla.-- Comunicación presentada en el Workshop de Mineralogía Aplicada Homenaje al Prof. Emilio Galán, Sevilla 16-17 Enero 2014Los minerales de arcilla se usan en numerosas aplicaciones industriales tales como soportes y plantillas en la producción de papel y plásticos; aislantes de calor en la industria de la construcción, pigmentos nacarados, agentes contra la corrosión en recubrimientos, agentes protectores contra UV y calor en pinturas, etc. En las últimas décadas se ha desarrollado un interés creciente por el uso de arcillas en tecnologías de vectores de principios activos a fin de conferir propiedades de liberación lenta, lo que es de particular interés en la industria farmacéutica y agroquímica.Esta investigación recibió financiación a través de los proyectos PRI-PIBAR-2011-1393-y CTM2009-07425.Peer Reviewe

Formulaciones del herbicida Imazaquín basadas en arcillas pilareadas para reducir su lixiviación en suelos

4 páginas.-- 4 figuras.-- 3 tablas.-- 5 referencias.-- Ponencia presentada en el VI Congreso Ibérico de la Ciencia del Suelo . Santiago de Compostela 22 al 25 de junio de 2014.Formulaciones de liberación lenta del herbicida imazaquín (IMZQ) fueron preparadas mediante su adsorción en minerales de la arcilla pilareados con óxidos de Fe (Fe PILC). Las proporciones Fe/(Fe+Al) utilizadas fueron 0, 0.05, 0.15 y 0.50. Conforme aumentaba el contenido de Fe, las arcillas pilareadas obtenidas presentaban menos microporosidad y mayor mesoporosidad. La afinidad de IMZQ por Fe PILC fue muy alta en comparación con Al PILC, observándose mayores porcentajes de adsorción del herbicida y menores porcentajes de desorción. Las formulaciones de liberación lenta fueron preparadas aumentando además la adsorción del herbicida a partir de soluciones de complejos IMZQ-ciclodextrina. La ciclodextrina (CD) seleccionada fue capaz de aumentar en 8.5 veces la solubilidad del herbicida. La lixiviación de IMZQ a partir de las formulaciones con Fe PILC preparadas fue la mitad de la que se obtenía con la formulación comercial.Peer reviewe

Removal of microorganisms by clay-polymer complexes

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Fe-pillared clay mineral-based formulations of imazaquin for reduced leaching in soil

Slow release formulations of the herbicide imazaquin (2-(4-isopropyl-4-methyl-5-oxo-4,5-dihydro-1H-imidazol-2-yl)quinoline-3-carboxylic acid) were prepared by its adsorption on Fe-pillared clay minerals (Fe PILCs). Fe PILCs were synthesized by the reaction of Na+-montmorillonite (SWy-2) with base-hydrolyzed solutions of Fe and Al. The Fe/(Fe+Al) ratios used were 0, 0.05, 0.15 and 0.50. Fe PILCs showed basal spacing values of 5.2 and 1.8nm which were due to iron clusters between delaminated clay layers, and intercalated aluminum polyoxocations, respectively. As iron content increased, the pillaring process yielded PILC with lower microporosity and larger mesoporosity. The affinity of imazaquin on Fe PILCs was very high relative to Al PILC, as revealed in its higher herbicide adsorption values and lower desorption percents. Competitive adsorption of anions such as sulfate, phosphate and chloride provided evidence of formation of inner sphere complexes of imazaquin on Fe PILCs. Slow release formulations were prepared by enhanced adsorption of the herbicide from imazaquin-cyclodextrin (CD) complexes in solution. CDs were able to enhance up to 8.5-fold the solubility of imazaquin, by the formation of inclusion complexes where the quinolinic moiety of the herbicide was partially trapped within the CD cavity. Release of the herbicide in sandy soil was about 1/2-fold lower from Fe PILC formulations relative to the commercial formulation.Ministerio de Educación y Ciencia CTM2009-07425Junta de Andalucía P09-RNM458

Fe-pillared clay mineral-based formulations of imazaquin for reduced leaching in soil

8 pages, 7 figures, 6 tables, 64 references.Slow release formulations of the herbicide imazaquin (2-(4-isopropyl-4-methyl-5-oxo-4,5-dihydro-1H-imidazol-2-yl)quinoline-3-carboxylic acid) were prepared by its adsorption on Fe-pillared clay minerals (Fe PILCs). Fe PILCs were synthesized by the reaction of Na+-montmorillonite (SWy-2) with base-hydrolyzed solutions of Fe and Al. The Fe/(Fe+Al) ratios used were 0, 0.05, 0.15 and 0.50. Fe PILCs showed basal spacing values of 5.2 and 1.8nm which were due to iron clusters between delaminated clay layers, and intercalated aluminum polyoxocations, respectively. As iron content increased, the pillaring process yielded PILC with lower microporosity and larger mesoporosity. The affinity of imazaquin on Fe PILCs was very high relative to Al PILC, as revealed in its higher herbicide adsorption values and lower desorption percents. Competitive adsorption of anions such as sulfate, phosphate and chloride provided evidence of formation of inner sphere complexes of imazaquin on Fe PILCs. Slow release formulations were prepared by enhanced adsorption of the herbicide from imazaquin-cyclodextrin (CD) complexes in solution. CDs were able to enhance up to 8.5-fold the solubility of imazaquin, by the formation of inclusion complexes where the quinolinic moiety of the herbicide was partially trapped within the CD cavity. Release of the herbicide in sandy soil was about 1/2-fold lower from Fe PILC formulations relative to the commercial formulation.This research was supported by the MEC Project CTM2009-07425 and the Junta de Andalucía Project P09-RNM4581. Both projects received funding by the European Social Fund.Peer Reviewe

Filtration of microorganisms by clay-polymer complexes.

4 páginas.-- 1 figura.-- 1 tabla.-- 2 referencias.-- Poster presentado en The 13th Leading Edge Conference on Water and Wastewater Technologies. Jerez de la Frontera (España). 2016. "Evaluating Impacts of Innovation" 13-16 june (2016) Jerez de la Frontera (Cádiz) EspañaClay-polymer composites were designed for use in filtration processes for disinfection during the course of water purification. The composites were formed by sorption of polymers based on starch modified with quatemary ammonium ethers onto the negatively charged clay mineral bentonite. The antimicrobial effect exerted by the clay-polymer system was due to the cationic monomers adsorbed on the clay surface, which resulted in a positive surface potential of the complexes and charge reversal. Clay-polymer complexes were more toxic to bacteria than the polymers alone. Filtration employing our optimal clay-polymer composite yielded 100 % removal of bacteria after the passage of 3 L, whereas an equivalent filter with granular activated carbon (GAC) hardly yielded removal of bacteria after 0.5 L.Peer Reviewe