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Controlled release of isoproturon from an alginate–bentonite formulation: water release kinetics and soil mobility
Author(s) -
VillafrancaSánchez M,
GonzálezPradas E,
FernándezPérez M,
MartinezLópez F,
FloresCéspedes F,
UreñaAmate M D
Publication year - 2000
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/1526-4998(200009)56:9<749::aid-ps196>3.0.co;2-#
Subject(s) - bentonite , sorption , chemistry , sodium alginate , kinetics , leaching (pedology) , active ingredient , nuclear chemistry , environmental chemistry , sodium , pulp and paper industry , adsorption , chemical engineering , soil water , environmental science , soil science , organic chemistry , physics , quantum mechanics , engineering , bioinformatics , biology
The herbicide isoproturon [3‐(4‐isopropylphenyl)‐1,1‐dimethylurea] was incorporated in alginate‐based granules to obtain controlled‐release (CR) properties. The basic formulation (sodium alginate (1.87%)–isoproturon (0.67%) in water) was modified by addition of different sorbents. The effect on isoproturon release rate, modified by the incorporation of natural and acid‐treated bentonite in alginate formulation, was studied by immersion of the granules in water while shaking. The release of isoproturon was diffusion‐controlled. The time taken for 50% of the active ingredient to be released into water, T 50 , was longer for those formulations containing added bentonite (5.98 and 7.43 days, for natural and acid‐treated (1 M H 2 SO 4 ) bentonite, respectively) than for the preparation without bentonite (3.78 days). The mobilities of non‐formulated technical grade (98%) and formulated isoproturon were compared using soil columns. The use of alginate‐based CR formulations containing bentonite reduced isoproturon movement compared with the technical product. Sorption capacity of the soil for isoproturon was measured using batch experiments (0.29 litre kg −1 ) and the results obtained here in agreement with those obtained under dynamic conditions. © 2000 Society of Chemical Industry