1. Cocrystal engineering for sustained release of dicamba: Mitigating secondary drift and reducing leaching.
- Author
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Wu, Chuanhua, Xiao, Yuntian, Wang, Na, Huang, Xin, Wang, Ting, Zhou, Lina, and Hao, Hongxun
- Subjects
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SUSTAINABLE agriculture , *NON-target organisms , *FAVA bean , *X-ray powder diffraction , *DICAMBA , *HERBICIDES - Abstract
The off-target effects of herbicides present significant challenges in agricultural practices, posing serious threats to both ecological systems and human health. Dicamba, one of the most widely used herbicides, is particularly problematic due to its high volatility and water solubility, which can lead to rapid environmental dispersal, non-target toxicity, and groundwater contamination. To mitigate these issues, we synthesized a novel cocrystal of dicamba and phenazine (DCB-PHE cocrystal) through a combination of theoretical prediction and mechanochemical screening. The DCB-PHE cocrystal was characterized using single-crystal and powder X-ray diffraction, Fourier-transform infrared spectroscopy (FT-IR), and thermal analysis. Compared to pure dicamba, the DCB-PHE cocrystal exhibited a substantial reduction in volatility by 59 % and a decrease in equilibrium solubility by up to 5.4 times across various temperatures (15 °C, 25 °C, 35 °C). Additionally, the dissolution rates were significantly lowered by over 94 %. Leaching experiments demonstrated that the DCB-PHE cocrystal reduced total leachate by 4.9 % and delayed percolation. In greenhouse trials, the DCB-PHE cocrystal caused less damage to exposed soy plants and enhanced herbicidal activity against target weeds, with fresh weight reduction of chicory and ryegrass by 32 % and 28 %, respectively, at the highest dosage. Furthermore, safety assays confirmed that the DCB-PHE cocrystal's safety profile was comparable to that of dicamba in terms of its impact on wheat, and it did not exhibit increased genotoxicity to broad beans. These findings suggest that the DCB-PHE cocrystal is a promising candidate for reducing the environmental impacts of dicamba while maintaining its herbicidal efficacy. The DCB-PHE cocrystal, prepared via supramolecular self-assembly, reduces drift, slows release, and decreases leaching rates into groundwater, contributing significantly to the development green and efficient agriculture. [Display omitted] • DCB-PHE cocrystal is prepared via mechanochemical and solution methods. • DCB-PHE cocrystal reduces the volatility of dicamba, minimizing soybean leaf damage. • DCB-PHE cocrystal significantly decreases solubility and dissolution rates at various temperatures. • DCB-PHE cocrystal lowers the leaching rate of dicamba into groundwater. • DCB-PHE cocrystal enhances herbicidal activity without increasing non-target toxicity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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