摘要
首次尝试将十六烷基三甲基铵盐阳离子改性的有机膨润土（CTMAB-Bents）用作乙草胺的吸附剂和控制释放载体。结果表明，与原土（Na-Bent）相比，CTMAB-Bents对乙草胺的吸附能力提高3-5倍，且吸附能力与改性膨润土所用CTMAB量成正相关。吸附等温曲线符合Freundlich经验方程，相关系数R〉0．99，吸附能力主要取决于乙草胺在水和有机膨润土间的分配作用。与Na-Bent相比，CTMAB-Bents可以显著抑制乙草胺的释放速率，对乙草胺的半数释放时间（t50）介于20CTMAB-Bent制剂的6．57h与100CTMAB-Bent制剂的19．0h之间，并随改性膨润土对乙草胺吸附能力的提高而延长。释放动力学曲线符合Ritger和Peppas方程，n值（0．429-0．618）接近Fickian扩散模型，说明乙草胺在有机膨润土中的释放主要受到扩散控制。
Bentonites modified with the organic cation cetyltrimethylammonium （CTMAB-Bents） were utilized as adsorbents and controlled release carders of acetochlor. The experimental results indicated that CTMAB-Bents provided 3 -5 times higher adsorptive capacities of acetochlor than the raw bentonite （Na-Bent） ,and their adsorptive capacities positively related to the amount of CTMAB used in modification. The adsorption isotherms were fit to the Freundlich equation with correlation coefficients R 〉 0.99. The adsorptive capacity mainly resulted from the partition of acetochlor between water and organo-bentonites. Compared with Na-Bent, CTMAB-Bents could apparently retard the release of acetochlor. The time taken for 50% of the acetochlor to be released （ t50 ） ranged from 6.57 h for the 20CTMAB-Bent formulation to 19.0 h for the 100CTMAB-Bent formulation. The prolonged t50 was consistent with the increased adsorptive capacity of the bentonites. The release dynamics were fit to the Ritger and Peppas equation with n values （0. 429 - 0. 618 ） close to that of Fickian diffusion model, which indicated a diffusion-dominated release mechanism of acetochlor from organo-bentonites.
出处
《农药学学报》
CAS
CSCD
2007年第4期390-396,共7页
Chinese Journal of Pesticide Science
基金
浙江省自然科学基金资助项目(Y506288,Y307106)
绍兴市科技计划项目(2006A32004)
关键词
乙草胺
除草剂
膨润土
控制释放
acetochlor
herbicide
bentonite
controlled release
