Synthesis and controlled release properties of 2,4-dichlorophenoxy
acetate–zinc layered hydroxide nanohybrid

Abbas M. Bashi a,n, Mohd Zobir Hussein b, Zulkarnain Zainal b, Didier Tichit c

1. Introduction
The increasing use of the agrochemicals in agricultural activities is
one of the main sources of water pollution. Pesticides are generally
combined to other materials to give formulated compounds which
must be optimized to reduce pesticide levels in the environment and
provide precise delivery to the target. For this purpose, controlled
release formulations which allow much less pesticide to be used are
developed. These formulations are generally obtained by encapsulation
of the active compounds in amatrix. Several natural and synthetic
materials have been proposed as matrix to achieve controlled release
formulation of pesticides, particularly clay minerals, layered double
hydroxides (LDH) and layered metal hydroxides (LMH). These two
latter materials are interesting host nanomaterials for controlled
release of anionic type pesticides. They are indeed formed of positively
charged brucite-like layers, and exchangeable anions as well as water
molecules are situated in the interlayer spaces. Therefore, organic–
inorganic nanohybrids can be obtained when anionic pesticide species
are introduced in the interlayer space of the LDH or LMH host
structures directly during synthesis achieved by co precipitation or
by other well known methods, such as anionic exchange or reconstruction
of the calcined LDH precursors.
The 2,4-dichlorophenoxyacetic acid, one of the widely used
herbicides, is highly contaminant due to its mobility and poor