TY - JOUR
T1 - Characterizing and designing polycation - Clay nanocomposites as a basis for imazapyr controlled release formulations
AU - Radian, Adi
AU - Mishael, Yael G.
PY - 2008/3/1
Y1 - 2008/3/1
N2 - A novel controlled release formulation (CRF) of the herbicide imazapyr (IMP) was designed to reduce its leaching, which causes soil and water contamination. The anionic herbicide IMP was bound to polydiallyldimethylammonium-chloride (PDADMAC)-montmorillonite composites. PDADMAC adsorption reached a high loading of polymer, which resulted in charge reversal of the clay and promoted IMP binding. The composites were characterized by Fourier transform infrared, zeta potential, and X-ray diffraction measurements, indicating electrostatic interactions of the polycation with the surface, polycation intercalation in the clay and suggesting a configuration as loops and tails on the surface at high loadings. IMP binding to the composites is affected by polycation loading and flocculation. Upon adding high concentrations of IMP to a composite of 0.16 g/g, we obtained high herbicide loadings (66% active ingredient). IMP release from the CRFs applied on a thin layer of soil was substantially slower than its release from the commercial formulation (Arsenal). Accordingly, soil column bioassays indicated reduced herbicide leaching (nearly 2-fold) upon applying the CRFs while maintaining good herbicidal activity. The new PDADMAC-clay formulations are promising from the environmental and weed control management points of view.
AB - A novel controlled release formulation (CRF) of the herbicide imazapyr (IMP) was designed to reduce its leaching, which causes soil and water contamination. The anionic herbicide IMP was bound to polydiallyldimethylammonium-chloride (PDADMAC)-montmorillonite composites. PDADMAC adsorption reached a high loading of polymer, which resulted in charge reversal of the clay and promoted IMP binding. The composites were characterized by Fourier transform infrared, zeta potential, and X-ray diffraction measurements, indicating electrostatic interactions of the polycation with the surface, polycation intercalation in the clay and suggesting a configuration as loops and tails on the surface at high loadings. IMP binding to the composites is affected by polycation loading and flocculation. Upon adding high concentrations of IMP to a composite of 0.16 g/g, we obtained high herbicide loadings (66% active ingredient). IMP release from the CRFs applied on a thin layer of soil was substantially slower than its release from the commercial formulation (Arsenal). Accordingly, soil column bioassays indicated reduced herbicide leaching (nearly 2-fold) upon applying the CRFs while maintaining good herbicidal activity. The new PDADMAC-clay formulations are promising from the environmental and weed control management points of view.
UR - http://www.scopus.com/inward/record.url?scp=40949089693&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=40949089693&partnerID=8YFLogxK
U2 - 10.1021/es7023753
DO - 10.1021/es7023753
M3 - Article
C2 - 18441796
AN - SCOPUS:40949089693
SN - 0013-936X
VL - 42
SP - 1511
EP - 1516
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 5
ER -