纳米TiO₂降解源复合型农药制剂

来源期刊：中南大学学报(自然科学版)2004年第4期

论文作者：司士辉 颜昌利 刘国聪 刘迪 王跃龙 王晓光

文章页码：591 - 594

关键词：纳米TiO₂;硬脂酸;农药;光降解;压电石英微天平

Key words：nanocrystalline TiO₂; stearic acid; pesticide; photodegradation; quartz crystal microbal Ance

摘    要：采用压电石英微天平技术研究了有机农药甲基对硫磷在经硬脂酸改性前、后纳米TiO₂上的吸附行为。研究结果表明:硬脂酸能提高纳米TiO₂对非极性有机农药的吸附量,甲基对硫磷分子在改性后的纳米TiO₂上的吸附符合Langmuir吸附,最大吸附量Г_∞为1.4×10^-3mol/g,吸附常数k为5.5×10^-5L/mol;亲脂性农药可与硬脂酸改性后的纳米TiO2形成稳定的复合体,复合纳米TiO₂农药制剂可在太阳光照下自行降解,在农作物体内的残留期大大缩短,且复合纳米TiO₂农药制剂的毒力明显提高,质量分数为10%的纳米乳液的毒力是质量分数为95%的原药毒力的1.68倍。

Abstract: A quartz crystal microbalance was used to investigate the adsorption behavior of methyl parathion on nanocrystalline TiO₂ particles modified with and without stearic acid, respectively. The results show that the hydrophilic property of nanocrystalline TiO₂ is changed into lipophilic property after the surface of the nanocrystalline TiO₂ particles is modified with stearic acid, and the nanocrystalline TiO₂ modified with stearic acid has better ability to adsorb non-polar organic pesticides than the original TiO₂. It is also found that the amount of the methyl parathion adsorbed on the surface of nanocrystalline TiO₂ modified with stearic acid is 1.4×10^-3mol/g, and the constant of the adsorption is 5.5×10⁵L/mol. The nanosized TiO₂-pesticide complex was prepared, and its photodegradation and biological toxicity were studied. Experimental results show that the nanosized TiO₂-pesticide complex has obvious photodegradation. Its residual time in the body of plant is significantly reduced and its biological toxicity is increased to 1.68 times that of traditional pesticides.