Novel slow-release nanohybrid from zinc hydroxysalt intercalated with dicamba herbicide

Dicamba was intercalated by co-precipitation into a zinc-layered hydroxide salt (LHS) to create a slow-release nanohybrid weed control without leaching. The X-Ray Powder Diffractometry (XRPD) patterns of the LHS intercalated with dicamba showed a basal spacing of 20.48 Å and 26.10 Å, confirming its allocation as a monolayer and bilayer interdigitated arrangement, respectively. The Fourier Transformant Infrared (FTIR) spectrum showed bands typical of dicamba and provided information about its bridging bidentate coordination to the matrix layer. The thermogravimetric analysis (TGA) estimated the compound's formula as Zn₅(OH)₈(dicamba)₂·4.14H₂O. The thermal stability of the LHS/dicamba system, the stages of mass loss, the characterization of the compounds released in the pyrolysis, the activation energy (E_a), and the kinetics were all analyzed. The average activation energy for decomposition of intercalated dicamba indicates that the thermal degradation occurred with the breakage of covalent bonds. Controlled release of dicamba from its nanohybrid in water was observed for 962 h (40 days). The pseudo-second-order model described the release process satisfactorily from its linear fitting, suggesting intraparticle diffusion or surface diffusion control. In summary, the intercalation of dicamba in the zinc LHS produced a slow-release material that can aid in weed control.