Layered Double Hydroxides for Efficient Delivery of Pesticides.
Man Park, Dept of Agricultural Chemistry, Kyungpook National Univ, Deagu, 702-701, South Korea and Sridhar Komarneni, Pennsylvania State Univ, Hastings Road, Materials Research Laboratory, University Park, PA 16802.
Heavy application of highly toxic pesticides had been committed to protect agricultural products against insects and plant diseases, which have brought about serious problems. Not only do pesticides contaminate air, soil, and water environments but also their subsequent bioaccumulation exerts acute toxicity on all kinds of biosystems including human beings. We have attempted to hybridize various pesticides with the Layered Double Hydroxides (LDHs), the soil-compatible inorganic matrixes in order to efficiently deliver pesticides. LDHs exhibit unique properties such as anion exchange capacity, acid lability, and high affinity to ubiquitous carbonate ion. In particular, acid lability and carbonate affinity make LDHs an excellent matrix to carry labile pesticides because these properties facilitate complete and controlled release of the intercalated pesticide along with beneficial effects on many cultivated soils typically developing acidic characteristics. Furthermore, the pesticides intercalated between the 2-dimensional inorganic layers could be safely protected against biological, chemical and thermodynamical degradations in soils. It is also plausible that their molecular-level arrangement within confined interlayer space leads to great enhancement of water-solubility, which implies reasonable exclusion of harmful solvents and surfactants from pesticide formulations. In addition, high dispersion ability of the hybrid could be readily accomplished by fine control on the particle size within submicron level. All these advantaged have been visualized in this presentation by two representative pesticide-LDH hybrids, cinnamate-LDH and MCPP-LDH.