Mariano J. L. Castro

Advances in surfactants for agrochemicals

Pesticide efficacy is improved by surfactants. Increase in the foliar uptake is particularly useful for herbicides, growth regulators and defoliants, because less active compounds are needed, thus decreasing cost and pollution. Therefore, the choice of the adjuvant in an agrochemical formulation is crucial. The surfactants commonly used as adjuvants include anionic, non-ionic, amphoteric and cationic surfactants. This review analyses the role and properties of the new adjuvants for agriculture and the improvement of the ecotoxicity profile of the pesticide formulations in glyphosate formulation.

Degradation of monensin on soils: influence of organic matter and water content

Different kinds of pharmaceutical compounds (PhC) are used in veterinary medicine. Intensive bovine production involves the use of growth promoters that reach the environment through animal excreta. The most widely used growth promoter in Argentina is monensin, an ionophore antibiotic. In this work, the influence of soil organic matter and soil water content on the degradation of monensin was analysed. Results obtained show that both parameters are in direct relation with the degradation of monensin in soils.

Synthesis of sugar-based chelating surfactants for metal removal from wastewater

Four chelating surfactants were synthesized in a few steps from octyl D-glucosides. Their main interfacial properties were determined, and their flotation properties were evaluated on a laboratory scale using Fe(III) as a model contaminant metal. The performance on metal extraction was mainly dependent on the complexing functional group, but the surfactant efficiency was also important.

Synthesis of new chelating surfactants from octyl d-glucopyranosiduronic acid and amino acids for metal flotation

A new family of surfactants with metal-chelating properties was synthesized in few steps from octyl D-glucopyranosiduronic acid. The complexing function was either a carboxylic acid or a hydroxamic acid function introduced after coupling with glycine, aspartic acid, or glutamic acid and finally hydroxylamine. Interfacial properties were determined. Flotation experiments on a laboratory scale have been performed with Fe(III) solutions as model contaminant metal.

Synthesis of New Dimeric Amphiphiles. Influence of Anomeric Configuration and Spacer Functionality on Interfacial Properties

ABSTRACT The synthesis of new dimeric carbohydrate-based surfactants was performed connecting two butyl glucopyranosides with a spacer through ester and ether linkages. Critical micellar concentrations were determined to study the influence of anomeric configuration and spacer functionality on surfactant properties.

Surfactants in Agriculture

Adjuvants such as surfactants improve pesticide efficiency by multiple mechanisms. In particular surfactants increase the foliar uptake of herbicides, growth regulators, and defoliants. Therefore, the choice of the adjuvant in an agrochemical formulation is crucial. Surfactants include anionic, nonionic, amphoteric and cationic surfactants. This review describes the role and properties of new adjuvants for agriculture. In particular adjuvants such as glyphosate formulations are modified to decrease ecotoxicity.

Structure-Properties Relationship of Dimeric Surfactants from Butyl Glucosides

Carbohydrate containing dimeric surfactants were synthesized starting from Dglucose. Three different spacers were used to link the sugar moieties. The critical micelle concentration (CMC) for these new compounds was determined.

Effect of feedlot design and management on the fate and distribution of monensin

Feedlots produce a range of trace chemicals that impact human health and/or the environment. The most widely used growth promoter in intensive cattle production in Argentina is monensin, an ionophore polyether with antibacterial and coccidiostatic activity. Several beef cattle feedlots with different management systems, weather conditions, feed types and feedbunk types were selected in different agro-ecological areas of Argentina. Monensin concentrations in samples of pen soil, manure, feed and runoff were analysed. The monensin concentrations measured in soil samples suggest a strong dependence on the type of feed employed in the facility. During feed distribution by trucks to the feedbunks, some feed can reach the soil, thereby increasing the soil monensin concentration close to the feedbunks. The wide range of monensin concentrations detected in manure samples could be explained by the rapid degradation of monensin in the manure matrix. Monensin levels in runoff samples indicated that the distribution of monensin in the environment could be governed by surface phenomena including horizontal movement and adsorption of monensin in particulate material present in the runoff layers. This is the first study of monensin distribution in Argentinian feedlots and serves as the starting point for more sustainable and environmentally friendly feedlot management.

O-Sulfated Derivatives of Glucuronic Acid

4-O-Substituted D-glucuronic acid derivatives were synthesized from D-glucose in order to study the regioselectivity of sulfation.