Influence of adjuvants on physicochemical properties, droplet size spectra and deposit patterns: relevance in pesticide applications

The influence of adjuvants on physicochemical properties, droplet size spectra and deposit patterns of five aqueous spray mixtures was studied under laboratory conditions, using two surfactants, Atlox 3409F and Triton X-114; two humectants, propylene glycol and glycerol; and one polymeric adjuvant, Agrisol FL-100F. For the sake of comparison, two fenitrothion formulations containing polymeric adjuvants, and water were also included in the study. Spray was applied at 25 degrees C and 75 +/- 5% relative humidity, in an enclosure using a twin fluid atomizer. Deposits were collected on Kromekote card/glass plate units. Physicochemical properties studied were: relative viscosity, surface tension, apparent viscosity-shear rate relationship, volatility, pH and conductance. The first four of these properties played significant roles on the droplet and deposit patterns on sampling units. However, the chemical nature of the adjuvants also played some role. Between the two surfactants tested, Triton X-114 provided a pseudoplastic medium, but both surfactant solutions provided similar droplet size spectra and deposit patterns. Between the two humectants, glycerol proved to be more advantageous than propylene glycol. The polymeric adjuvant provided droplet sizes similar to those of the two surfactants, although the recovery of the applied spray volume was higher. Among the two fenitrothion formulations, the one containing lower amounts of polymeric adjuvants showed some advantages, although deposits on the actual biological target should be examined before any definite conclusions can be drawn on the optimum adjuvant concentrations in end-use formulations.     

Influence of surfactants and polymeric adjuvants on physicochemical properties, droplet size spectra and deposition of fenitrothion and Bacillus thuringiensis formulations under laboratory conditions

The effect of two surfactants and two polymeric adjuvants on droplet size spectra and deposition patterns of nine spray formulations was investigated following atomization in a laboratory chamber using a spinning disc atomizer that can produce a narrow droplet size spectrum. Spray droplets were sampled using Kromekote cards and deposit recoveries were examined on glass plates. Physicochemical properties studied were: viscosity-shear rate relationship, surface tension, volatility, pH, conductance, electrophoretic mobility and zeta potential. Formulations containing low surfactant concentrations provided Newtonian liquids with low viscosities. These liquids atomized into small droplets and provided low recoveries of spray deposits on sampling units. However, formulations containing polymeric adjuvants, and a high concentration of a non-ionic surfactant provided pseudoplastic liquids with high viscosities. These formulations resulted in large droplets with high recoveries of spray deposits on sampling units. Among the physicochemical properties studied, viscosity, surface tension, volatility and electrophoretic mobility, played important roles on liquid atomization and droplet deposition.     

Effect of depth of landfill on the characteristics of soil-like material of aged waste: a case study of Bhalswa dumpsite,India

Journal of Material Cycles and Waste Management - This study characterizes the municipal solid waste (MSW) accumulated for more than 25 years at Bhalswa dumpsite, Delhi, India. 50...