Use of Activated Bentonites in Controlled-Release Formulations of Atrazine

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• 作者：Manuel Fern&aacute ; ndez-Pé ; rez ; Francisco Flores-Cé ; spedes ; Emilio Gonz&aacute ; lez-Pradas ; Matilde Villafranca-S&aacute ; nchez ; Susana Pé ; rez-Garcí ; a ; and Francisco Javier Garri
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2004
• 出版时间：June 16, 2004
• 年：2004
• 卷：52
• 期：12
• 页码：3888 - 3893
• 全文大小：72K
• 年卷期：v.52,no.12(June 16, 2004)
• ISSN：1520-5118

文摘

The herbicide atrazine (6-chloro-N<SUP>2-ethyl-N⁴-isopropyl-1,3,5-triazine-2,4-diamine) was incorporatedin alginate-based granules to obtain controlled-release (CR) properties. The basic formulation [sodiumalginate (1.40%)-atrazine (0.60%)-water] was modified by the addition of sorbents. The effect onatrazine release rate caused by the incorporation of acid-treated bentonite (0.5 and 2.5 M H₂SO₄) inalginate formulation was studied by immersion of the granules in water under static conditions. Thewater uptake, sorption capacity of the sorbent, permeability, and time taken for 50% of the activeingredient to be released into water, t₅₀, were calculated for the comparison of the preparations. t₅₀values were longer for those formulations containing acid-treated bentonite (36.78 and 29.01 daysfor 0.5 and 2.5 M H₂SO₄ treatments, respectively) than for the preparation without bentonite (9.69days). On the basis of a parameter of an empirical equation used to fit the herbicide release data, itappears that the release of atrazine from the various formulations into water is controlled by diffusionmechanism. The sorption capacity of the sorbents and the permeability of the formulations (rangingfrom 4.99 to 20.83 mg day^-1 mm^-1) were the most important factors affecting herbicide release.Keywords: Atrazine; controlled release; activated bentonite; sorption