羧甲基壳聚糖/改性膨润土复合载体对莠去津释放和淋溶的影响

首次尝试将羧甲基壳聚糖与改性膨润土复合用作除草剂莠去津的载体,制备得到控释型颗粒剂,以延缓莠去津的释放,减少淋溶损失,提高药效及控制其污染。通过水中释放实验研究了制剂配方对莠去津释放速率的影响,并借助半经验方程探讨了其释放机理,采用土壤薄层实验考察了复合载体对降低莠去津淋溶的效果。 结果表明,采用复合载体时莠去津的半数释放时间(t 50)可达700 h 以上,比对照采用单一羧甲基壳聚糖作载体时延长了1倍以上。莠去津由颗粒剂向水相释放的过程主要受费克扩散(Fickian diffusion)控制,且经9次淋洗后莠去津的累计淋出率仅为6.0%,表明该复合载体控释制剂可显著减少莠去津对地下水的污染。

Influence of carboxymethyl-chitosan /modified bentonite composite carrier on the release and leaching of atrazine

Carboxymethyl-chitosan (CMC) was combined with modified bentonite,and used as the carrier of herbicide atrazine to prepare granular formulations with controlled release function,so as to slower its release,reduce its leaching,enhance its efficacy and control its pollution.The release experiments in water were used to investigate the influence of formulations on the release rate of atrazine.The release mechanism was discussed by using a semi-empirical model.The experiments on a thin soil layer were used to investigate the effect of composite carrier on reducing the leaching of atrazine.The results showed that,the time taken for 50% of atrazine released ( t ₅₀) was prolonged to more than 700 h by using the composite carrier,which is 2 times longer than using CMC alone as the carrier.The release process was dominated by the Fickian diffusion,and the cumulative percentage of atrazine leached was only 6.0% after 9 times of rinsing with water,in this way the pollution of atrazine to groundwater may be greatly reduced.