Preparation of a new stable hybrid material by chloride–2,4-dichlorophenoxyacetate ion exchange into the zinc–aluminium–chloride layered double hydroxide

A new hybrid material with the composition [Zn1.9Al(OH)5.8][Cl2C6H3OCH2CO2·2.83H2O] has been synthesised via ion exchange of chloride by ions of a molecule belonging to the pesticide family, 2,4-dichlorophenoxyacetate (2,4D). The ion exchange in the zinc–aluminium–chloride layered double hydroxide, [Zn–Al–Cl], was investigated by X-ray diffraction and infrared spectroscopy. The effects of the anion concentration in solution, the 2,4D/[Zn–Al–Cl] molar ratio, the ageing time and the temperature on the ion exchange were studied. The best sample, in terms of crystallinity and extent of ion exchange, was obtained at 100 °C in a 0.004 M 2,4D solution in which the 2,4D/[Zn–Al–Cl] molar ratio was equal to 11, with 24 h of stirring time. This hybrid material was further characterised by chemical analyses and its thermal behaviour was also studied.