Use of bentonite and activated carbon in controlled release formulations of carbofuran.

Controlled release systems (CRS), unlike the conventional formulations, facilitate a gradual and controlled discharge of the pesticides, reducing the losses by evaporation and leaching and minimizing pesticide pollution. In this study, carbofuranan insecticide−nematicide identified as a groundwater pollutantwas incorporated in alginate-based granules to obtain controlled release properties. The effect on carbofuran release rate caused by the incorporation of bentonite, activated carbon, and different mixtures of both sorbents in alginate basic formulation was studied by immersion of the granules in water. The water uptake, sorption capacity of the sorbent, permeability, and time taken for 50% of the active ingredient to be released into water, T50, were calculated by the comparison of the preparations. T50 values were higher for those formulations containing bentonite and/or activated carbon (T50 values range from 14.76 h for the alginate formulation containing only bentonite as the sorbent to 29.5 weeks ...